<?xml version="1.0" encoding="UTF-8" ?>
<rdf:RDF xmlns="http://usefulinc.com/ns/doap#" xmlns:foaf="http://xmlns.com/foaf/0.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"><Project><name>zc.buildout</name>
<shortdesc>System for managing development buildouts</shortdesc>
<description>********
Buildout
********

.. contents::

The Buildout project provides support for creating applications,
especially Python applications.  It provides tools for assembling
applications from multiple parts, Python or otherwise.  An application
may actually contain multiple programs, processes, and configuration
settings.

The word "buildout" refers to a description of a set of parts and the
software to create and assemble them.  It is often used informally to
refer to an installed system based on a buildout definition.  For
example, if we are creating an application named "Foo", then "the Foo
buildout" is the collection of configuration and application-specific
software that allows an instance of the application to be created.  We
may refer to such an instance of the application informally as "a Foo
buildout".

To get a feel for some of the things you might use buildouts for, see
the `Buildout examples`_.

To lean more about using buildouts, see `Detailed Documentation`_.

Recipes
*******

Existing recipes include:

`zc.recipe.egg &lt;http://pypi.python.org/pypi/zc.recipe.egg&gt;`_
   The egg recipe installes one or more eggs, with their
   dependencies.  It installs their console-script entry points with
   the needed eggs included in their paths.

`zc.recipe.testrunner &lt;http://pypi.python.org/pypi/zc.recipe.testrunner&gt;`_
   The testrunner egg installs creates a test runner script for one or
   more eggs.

`zc.recipe.zope3checkout &lt;http://pypi.python.org/pypi/zc.recipe.zope3checkout&gt;`_
   The zope3checkout recipe installs a Zope 3 checkout into a
   buildout.

`zc.recipe.zope3instance &lt;http://pypi.python.org/pypi/zc.recipe.zope3instance&gt;`_
   The zope3instance recipe sets up a Zope 3 instance.

`zc.recipe.filestorage &lt;http://pypi.python.org/pypi/zc.recipe.filestorage&gt;`_
   The filestorage recipe sets up a ZODB file storage for use in a
   Zope 3 instance creayed by the zope3instance recipe.

Buildout examples
*****************

Here are a few examples of what you can do with buildouts.  We'll
present these as a set of use cases.

Try out an egg
==============

Sometimes you want to try an egg (or eggs) that someone has released.
You'd like to get a Python interpreter that lets you try things
interactively or run sample scripts without having to do path
manipulations.  If you can and don't mind modifying your Python
installation, you could use easy_install, otherwise, you could create
a directory somewhere and create a buildout.cfg file in that directory
containing::

  [buildout]
  parts = mypython

  [mypython]
  recipe = zc.recipe.egg
  interpreter = mypython
  eggs = theegg

where theegg is the name of the egg you want to try out.

Run buildout in this directory.  It will create a bin subdirectory
that includes a mypython script.  If you run mypython without any
arguments you'll get an interactive interpreter with the egg in the
path. If you run it with a script and script arguments, the script
will run with the egg in its path.  Of course, you can specify as many
eggs as you want in the eggs option.

If the egg provides any scripts (console_scripts entry points), those
will be installed in your bin directory too.

Work on a package
=================

I often work on packages that are managed separately.  They don't have
scripts to be installed, but I want to be able to run their tests
using the `zope.testing test runner
&lt;http://www.python.org/pypi/zope.testing&gt;`_.  In this kind of
application, the program to be installed is the test runner.  A good
example of this is `zc.ngi &lt;http://svn.zope.org/zc.ngi/trunk/&gt;`_.

Here I have a subversion project for the zc.ngi package.  The software
is in the src directory.  The configuration file is very simple::

  [buildout]
  develop = .
  parts = test

  [test]
  recipe = zc.recipe.testrunner
  eggs = zc.ngi

I use the develop option to create a develop egg based on the current
directory.  I request a test script named "test" using the
zc.recipe.testrunner recipe.  In the section for the test script, I
specify that I want to run the tests in the zc.ngi package.

When I check out this project into a new sandbox, I run bootstrap.py
to get setuptools and zc.buildout and create bin/buildout.  I run
bin/buildout, which installs the test script, bin/test, which I can
then use to run the tests.

This is probably the most common type of buildout.

The `zc.buildout project &lt;http://svn.zope.org/zc.buildout/trunk&gt;`_
is a slightly more complex example of this type of buildout.

Install egg-based scripts
=========================

A variation of the `Try out an egg`_ use case is to install scripts
into your ~/bin directory (on Unix, of course).  My ~/bin directory is
a buildout with a configuration file that looks like::


  [buildout]
  parts = foo bar
  bin-directory = .

  [foo]
  ...

whwre foo and bar are packages with scripts that I want available.  As
I need new scripts, I can add additional sections.  The bin-directory
option specified that scripts should be installed into the current
directory.

Multi-program multi-machine systems
===================================

Using an older prototype version of the buildout, we've build a number
of systems involving multiple programs, databases, and machines.  One
typical example consists of:

- Multiple Zope instances

- Multiple ZEO servers

- An LDAP server

- Cache-invalidation and Mail delivery servers

- Dozens of add-on packages

- Multiple test runners

- Multiple deployment modes, including dev, stage, and prod,
  with prod deployment over multiple servers

Parts installed include:

- Application software installs, including Zope, ZEO and LDAP
  software

- Add-on packages

- Bundles of configuration that define Zope, ZEO and LDAP instances

- Utility scripts such as test runners, server-control
  scripts, cron jobs.

Questions and Bug Reporting
***************************

Please send questions and comments to the
`distutils SIG mailing list &lt;mailto://distutils-sig@python.org&gt;`_.

Report bugs using the `zc.buildout Launchpad Bug Tracker
&lt;https://launchpad.net/products/zc.buildout/+bugs&gt;`_.


Detailed Documentation
**********************

Buildouts
=========

The word "buildout" refers to a description of a set of parts and the
software to create and assemble them.  It is often used informally to
refer to an installed system based on a buildout definition.  For
example, if we are creating an application named "Foo", then "the Foo
buildout" is the collection of configuration and application-specific
software that allows an instance of the application to be created.  We
may refer to such an instance of the application informally as "a Foo
buildout".  

This document describes how to define buildouts using buildout
configuration files and recipes.  There are three ways to set up the
buildout software and create a buildout instance:

1. Install the zc.buildout egg with easy_install and use the buildout
   script installed in a Python scripts area.

2. Use the buildout bootstrap script to create a buildout that
   includes both the setuptools and zc.buildout eggs.  This allows you
   to use the buildout software without modifying a Python install.
   The buildout script is installed into your buildout local scripts
   area.

3. Use a buildoput command from an already installed buildout to 
   bootstrap a new buildout.  (See the section on bootstraping later
   in this document.)

Often, a software project will be managed in a software repository,
such as a subversion repository, that includes some software source
directories, buildout configuration files, and a copy of the buildout
bootstrap script.  To work on the project, one would check out the
project from the repository and run the bootstrap script which
installs setuptools and zc.buildout into the checkout as well as any
parts defined.

We have a sample buildout that we created using the bootstrap command
of an existing buildout (method 3 above).  It has the absolute minimum
information.  We have bin, develop-eggs, eggs and parts directories,
and a configuration file:
    
    &gt;&gt;&gt; ls(sample_buildout)
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    d  parts

The bin directory contains scripts.

    &gt;&gt;&gt; ls(sample_buildout, 'bin')
    -  buildout

    &gt;&gt;&gt; ls(sample_buildout, 'eggs')
    -  setuptools-0.6-py2.4.egg
    -  zc.buildout-1.0-py2.4.egg

The develop-eggs and parts directories are initially empty:

    &gt;&gt;&gt; ls(sample_buildout, 'develop-eggs')
    &gt;&gt;&gt; ls(sample_buildout, 'parts')

The develop-eggs directory holds egg links for software being
developed in the buildout.  We separate develop-eggs and other eggs to
allow eggs directories to be shared across multiple buildouts.  For
example, a common developer technique is to define a common eggs
directory in their home that all non-develop eggs are stored in.  This
allows larger buildouts to be set up much more quickly and saves disk
space.

The parts directory provides an area where recipes can install
part data.  For example, if we built a custom Python, we would
install it in the part directory.  Part data is stored in a
sub-directory of the parts directory with the same name as the part.

Buildouts are defined using configuration files.  These are in the
format defined by the Python ConfigParser module, with extensions
that we'll describe later.  By default, when a buildout is run, it
looks for the file buildout.cfg in the directory where the buildout is
run.

The minimal configuration file has a buildout section that defines no
parts:

    &gt;&gt;&gt; cat(sample_buildout, 'buildout.cfg')
    [buildout]
    parts =

A part is simply something to be created by a buildout.  It can be
almost anything, such as a Python package, a program, a directory, or
even a configuration file.  

Recipes
-------

A part is created by a recipe.  Recipes are always installed as Python
eggs. They can be downloaded from a package server, such as the
Python Package Index, or they can be developed as part of a project
using a "develop" egg.  

A develop egg is a special kind of egg that gets installed as an "egg
link" that contains the name of a source directory.  Develop eggs
don't have to be packaged for distribution to be used and can be
modified in place, which is especially useful while they are being
developed.

Let's create a recipe as part of the sample project.  We'll create a
recipe for creating directories.  First, we'll create a recipes source
directory for our local recipes:

    &gt;&gt;&gt; mkdir(sample_buildout, 'recipes')

and then we'll create a source file for our mkdir recipe:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'mkdir.py', 
    ... """
    ... import logging, os, zc.buildout
    ...
    ... class Mkdir:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.name, self.options = name, options
    ...         options['path'] = os.path.join(
    ...                               buildout['buildout']['directory'],
    ...                               options['path'],
    ...                               )
    ...         if not os.path.isdir(os.path.dirname(options['path'])):
    ...             logging.getLogger(self.name).error(
    ...                 'Cannot create %s. %s is not a directory.',
    ...                 options['path'], os.path.dirname(options['path']))
    ...             raise zc.buildout.UserError('Invalid Path')
    ...             
    ...
    ...     def install(self):
    ...         path = self.options['path']
    ...         logging.getLogger(self.name).info(
    ...             'Creating directory %s', os.path.basename(path))
    ...         os.mkdir(path)
    ...         return path
    ...
    ...     def update(self):
    ...         pass
    ... """)

Currently, recipes must define 3 methods [#future_recipe_methods]_:

- a constructor,

- an install method, and

- an update method.

The constructor is responsible for updating a parts options to reflect
data read from other sections.  The buildout system keeps track of
whether a part specification has changed.  A part specification has
changed if it's options, after adjusting for data read from other
sections, has changed, or if the recipe has changed.  Only the options
for the part are considered.  If data are read from other sections,
then that information has to be reflected in the parts options.  In
the Mkdir example, the given path is interpreted relative to the
buildout directory, and data from the buildout directory is read.  The
path option is updated to reflect this.  If the directory option was
changed in the buildout sections, we would know to update parts
created using the mkdir recipe using relative path names.

When buildout is run, it saves configuration data for installed parts
in a file named ".installed.cfg".  In subsequent runs, it compares
part-configuration data stored in the .installed.cfg file and the
part-configuration data loaded from the configuration files as
modified by recipe constructors to decide if the configuration of a
part has changed. If the configuration has changed, or if the recipe
has changed, then the part is uninstalled and reinstalled.  The
buildout only looks at the part's options, so any data used to
configure the part needs to be reflected in the part's options.  It is
the job of a recipe constructor to make sure that the options include
all relevant data.

Of course, parts are also uninstalled if they are no-longer used.

The recipe defines a constructor that takes a buildout object, a part
name, and an options dictionary. It saves them in instance attributes.
If the path is relative, we'll interpret it as relative to the
buildout directory.  The buildout object passed in is a mapping from
section name to a mapping of options for that section. The buildout
directory is available as the directory option of the buildout
section.  We normalize the path and save it back into the options
directory.  

The install method is responsible for creating the part.  In this
case, we need the path of the directory to create.  We'll use a path
option from our options dictionary.  The install method logs what it's
doing using the Python logging call.  We return the path that we
installed.  If the part is uninstalled or reinstalled, then the path
returned will be removed by the buildout machinery.  A recipe install
method is expected to return a string, or an iterable of strings
containing paths to be removed if a part is uninstalled.  For most
recipes, this is all of the uninstall support needed. For more complex
uninstallation scenarios use `Uninstall recipes`_.

The update method is responsible for updating an already installed
part.  An empty method is often provided, as in this example, if parts
can't be updated.  An update method can return None, a string, or an
iterable of strings.  If a string or iterable of strings is returned,
then the saved list of paths to be uninstalled is updated with the new
information by adding any new files returned by the update method.

We need to provide packaging information so that our recipe can be
installed as a develop egg. The minimum information we need to specify
[#packaging_info]_ is a name.  For recipes, we also need to define the
names of the recipe classes as entry points.  Packaging information is
provided via a setup.py script:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... 
    ... setup(
    ...     name = "recipes",
    ...     entry_points = {'zc.buildout': ['mkdir = mkdir:Mkdir']},
    ...     )
    ... """)

Our setup script defines an entry point. Entry points provide
a way for an egg to define the services it provides.  Here we've said
that we define a zc.buildout entry point named mkdir.  Recipe
classes must be exposed as entry points in the zc.buildout group.  we
give entry points names within the group.

We also need a README.txt for our recipes to avoid an annoying warning
from distutils, on which setuptools and zc.buildout are based:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'README.txt', " ")

Now let's update our buildout.cfg:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mystuff
    ... """)

Let's go through the changes one by one::

    develop = recipes

This tells the buildout to install a development egg for our recipes.
Any number of paths can be listed.  The paths can be relative or
absolute.  If relative, they are treated as relative to the buildout
directory.  They can be directory or file paths.  If a file path is
given, it should point to a Python setup script.  If a directory path
is given, it should point to a directory containing a setup.py file.
Development eggs are installed before building any parts, as they may
provide locally-defined recipes needed by the parts.

::

    parts = data-dir

Here we've named a part to be "built".  We can use any name we want
except that different part names must be unique and recipes will often
use the part name to decide what to do.

::

    [data-dir]
    recipe = recipes:mkdir
    path = mystuff    


When we name a part, we also create a section of the same
name that contains part data.  In this section, we'll define
the recipe to be used to install the part.  In this case, we also
specify the path to be created.

Let's run the buildout.  We do so by running the build script in the
buildout:

    &gt;&gt;&gt; import os
    &gt;&gt;&gt; os.chdir(sample_buildout)
    &gt;&gt;&gt; buildout = os.path.join(sample_buildout, 'bin', 'buildout')
    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    data-dir: Creating directory mystuff

We see that the recipe created the directory, as expected:

    &gt;&gt;&gt; ls(sample_buildout)
    -  .installed.cfg
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    d  mystuff
    d  parts
    d  recipes

In addition, .installed.cfg has been created containing information
about the part we installed:

    &gt;&gt;&gt; cat(sample_buildout, '.installed.cfg')
    [buildout]
    installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
    parts = data-dir
    &lt;BLANKLINE&gt;
    [data-dir]
    __buildout_installed__ = /sample-buildout/mystuff
    __buildout_signature__ = recipes-c7vHV6ekIDUPy/7fjAaYjg==
    path = /sample-buildout/mystuff
    recipe = recipes:mkdir

Note that the directory we installed is included in .installed.cfg.
In addition, the path option includes the actual destination
directory. 

If we change the name of the directory in the configuration file,
we'll see that the directory gets removed and recreated:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mydata
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling data-dir.
    Installing data-dir.
    data-dir: Creating directory mydata

    &gt;&gt;&gt; ls(sample_buildout)
    -  .installed.cfg
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    d  mydata
    d  parts
    d  recipes

If any of the files or directories created by a recipe are removed,
the part will be reinstalled:

    &gt;&gt;&gt; rmdir(sample_buildout, 'mydata')
    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling data-dir.
    Installing data-dir.
    data-dir: Creating directory mydata

Error reporting
---------------

If a user makes an error, an error needs to be printed and work needs
to stop.  This is accomplished by logging a detailed error message and
then raising a (or an instance of a subclass of a)
zc.buildout.UserError exception.  Raising an error other than a
UserError still displays the error, but labels it as a bug in the
buildout software or recipe. In the sample above, of someone gives a
non-existent directory to create the directory in:


    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = /xxx/mydata
    ... """)

We'll get a user error, not a traceback.

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    data-dir: Cannot create /xxx/mydata. /xxx is not a directory.
    While:
      Installing.
      Getting section data-dir.
      Initializing part data-dir.
    Error: Invalid Path


Recipe Error Handling
---------------------

If an error occurs during installation, it is up to the recipe to
clean up any system side effects, such as files created.  Let's update
the mkdir recipe to support multiple paths:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'mkdir.py', 
    ... """
    ... import logging, os, zc.buildout
    ...
    ... class Mkdir:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.name, self.options = name, options
    ...
    ...         # Normalize paths and check that their parent
    ...         # directories exist:
    ...         paths = []
    ...         for path in options['path'].split(): 
    ...             path = os.path.join(buildout['buildout']['directory'], path)
    ...             if not os.path.isdir(os.path.dirname(path)):
    ...                 logging.getLogger(self.name).error(
    ...                     'Cannot create %s. %s is not a directory.',
    ...                     options['path'], os.path.dirname(options['path']))
    ...                 raise zc.buildout.UserError('Invalid Path')
    ...             paths.append(path)
    ...         options['path'] = ' '.join(paths)
    ...
    ...     def install(self):
    ...         paths = self.options['path'].split()
    ...         for path in paths: 
    ...             logging.getLogger(self.name).info(
    ...                 'Creating directory %s', os.path.basename(path))
    ...             os.mkdir(path)
    ...         return paths
    ...
    ...     def update(self):
    ...         pass
    ... """)

If there is an error creating a path, the install method will exit and
leave previously created paths in place:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = foo bin
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling data-dir.
    Installing data-dir.
    data-dir: Creating directory foo
    data-dir: Creating directory bin
    While:
      Installing data-dir.
    &lt;BLANKLINE&gt;
    An internal error occured due to a bug in either zc.buildout or in a
    recipe being used:
    &lt;BLANKLINE&gt;
    OSError:
    [Errno 17] File exists: '/sample-buildout/bin'

We meant to create a directory bins, but typed bin.  Now foo was
left behind.

    &gt;&gt;&gt; os.path.exists('foo')
    True

If we fix the typo:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = foo bins
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    data-dir: Creating directory foo
    While:
      Installing data-dir.
    &lt;BLANKLINE&gt;
    An internal error occured due to a bug in either zc.buildout or in a
    recipe being used:
    &lt;BLANKLINE&gt;
    OSError:
    [Errno 17] File exists: '/sample-buildout/foo'

Now they fail because foo exists, because it was left behind.

    &gt;&gt;&gt; remove('foo')

Let's fix the recipe:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'mkdir.py', 
    ... """
    ... import logging, os, zc.buildout
    ...
    ... class Mkdir:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.name, self.options = name, options
    ...
    ...         # Normalize paths and check that their parent
    ...         # directories exist:
    ...         paths = []
    ...         for path in options['path'].split(): 
    ...             path = os.path.join(buildout['buildout']['directory'], path)
    ...             if not os.path.isdir(os.path.dirname(path)):
    ...                 logging.getLogger(self.name).error(
    ...                     'Cannot create %s. %s is not a directory.',
    ...                     options['path'], os.path.dirname(options['path']))
    ...                 raise zc.buildout.UserError('Invalid Path')
    ...             paths.append(path)
    ...         options['path'] = ' '.join(paths)
    ...
    ...     def install(self):
    ...         paths = self.options['path'].split()
    ...         created = []
    ...         try:
    ...             for path in paths: 
    ...                 logging.getLogger(self.name).info(
    ...                     'Creating directory %s', os.path.basename(path))
    ...                 os.mkdir(path)
    ...                 created.append(path)
    ...         except:
    ...             for d in created:
    ...                 os.rmdir(d)
    ...             raise
    ...
    ...         return paths
    ...
    ...     def update(self):
    ...         pass
    ... """)

And put back the typo:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = foo bin
    ... """)

When we rerun the buildout:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    data-dir: Creating directory foo
    data-dir: Creating directory bin
    While:
      Installing data-dir.
    &lt;BLANKLINE&gt;
    An internal error occured due to a bug in either zc.buildout or in a
    recipe being used:
    &lt;BLANKLINE&gt;
    OSError:
    [Errno 17] File exists: '/sample-buildout/bin'

we get the same error, but we don't get the directory left behind:

    &gt;&gt;&gt; os.path.exists('foo')
    False

It's critical that recipes clean up partial effects when errors
occur.  Because recipes most commonly create files and directories,
buildout provides a helper API for removing created files when an
error occurs.  Option objects have a created method that can be called
to record files as they are created.  If the install or update method
returns with an error, then any registered paths are removed
automatically.  The method returns the files registered and can be
used to return the files created.  Let's use this API to simplify the
recipe:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'mkdir.py', 
    ... """
    ... import logging, os, zc.buildout
    ...
    ... class Mkdir:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.name, self.options = name, options
    ...
    ...         # Normalize paths and check that their parent
    ...         # directories exist:
    ...         paths = []
    ...         for path in options['path'].split(): 
    ...             path = os.path.join(buildout['buildout']['directory'], path)
    ...             if not os.path.isdir(os.path.dirname(path)):
    ...                 logging.getLogger(self.name).error(
    ...                     'Cannot create %s. %s is not a directory.',
    ...                     options['path'], os.path.dirname(options['path']))
    ...                 raise zc.buildout.UserError('Invalid Path')
    ...             paths.append(path)
    ...         options['path'] = ' '.join(paths)
    ...
    ...     def install(self):
    ...         paths = self.options['path'].split()
    ...         for path in paths: 
    ...             logging.getLogger(self.name).info(
    ...                 'Creating directory %s', os.path.basename(path))
    ...             os.mkdir(path)
    ...             self.options.created(path)
    ...
    ...         return self.options.created()
    ...
    ...     def update(self):
    ...         pass
    ... """)

..

    &gt;&gt;&gt; remove(sample_buildout, 'recipes', 'mkdir.pyc')

We returned by calling created, taking advantage of the fact that it
returns the registered paths.  We did this for illustrative purposes.
It would be simpler just to return the paths as before.

If we rerun the buildout, again, we'll get the error and no
directories will be created:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    data-dir: Creating directory foo
    data-dir: Creating directory bin
    While:
      Installing data-dir.
    &lt;BLANKLINE&gt;
    An internal error occured due to a bug in either zc.buildout or in a
    recipe being used:
    &lt;BLANKLINE&gt;
    OSError:
    [Errno 17] File exists: '/sample-buildout/bin'

    &gt;&gt;&gt; os.path.exists('foo')
    False

Now, we'll fix the typo again and we'll get the directories we expect:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = foo bins
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    data-dir: Creating directory foo
    data-dir: Creating directory bins

    &gt;&gt;&gt; os.path.exists('foo')
    True
    &gt;&gt;&gt; os.path.exists('bins')
    True

Configuration file syntax
-------------------------

As mentioned earlier, buildout configuration files use the format
defined by the Python ConfigParser module with extensions.  The
extensions are:

- option names are case sensitive

- option values can use a substitution syntax, described below, to
  refer to option values in specific sections.

The ConfigParser syntax is very flexible.  Section names can contain
any characters other than newlines and right square braces ("]").
Option names can contain any characters other than newlines, colons,
and equal signs, can not start with a space, and don't include
trailing spaces.

It is likely that, in the future, some characters will be given
special buildout-defined meanings.  This is already true of the
characters ":", "$", "%", "(", and ")".  For now, it is a good idea to
keep section and option names simple, sticking to alphanumeric
characters, hyphens, and periods.

Variable substitutions
----------------------

Buildout configuration files support variable substitution.
To illustrate this, we'll create an debug recipe to
allow us to see interactions with the buildout:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'debug.py', 
    ... """
    ... class Debug:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.buildout = buildout
    ...         self.name = name
    ...         self.options = options
    ...
    ...     def install(self):
    ...         items = self.options.items()
    ...         items.sort()
    ...         for option, value in items:
    ...             print option, value
    ...         return ()
    ...
    ...     update = install
    ... """)

This recipe doesn't actually create anything. The install method
doesn't return anything, because it didn't create any files or
directories.

We also have to update our setup script:

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... entry_points = (
    ... '''
    ... [zc.buildout]
    ... mkdir = mkdir:Mkdir
    ... debug = debug:Debug
    ... ''')
    ... setup(name="recipes", entry_points=entry_points)
    ... """)

We've rearranged the script a bit to make the entry points easier to
edit.  In particular, entry points are now defined as a configuration
string, rather than a dictionary.

Let's update our configuration to provide variable substitution
examples:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir debug
    ... log-level = INFO
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... File 1 = ${data-dir:path}/file
    ... File 2 = ${debug:File 1}/log
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mydata
    ... """)

We used a string-template substitution for File 1 and File 2.  This
type of substitution uses the string.Template syntax.  Names
substituted are qualified option names, consisting of a section name
and option name joined by a colon.

Now, if we run the buildout, we'll see the options with the values
substituted. 

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling data-dir.
    Installing data-dir.
    data-dir: Creating directory mydata
    Installing debug.
    File 1 /sample-buildout/mydata/file
    File 2 /sample-buildout/mydata/file/log
    recipe recipes:debug

Note that the substitution of the data-dir path option reflects the
update to the option performed by the mkdir recipe.

It might seem surprising that mydata was created again.  This is
because we changed our recipes package by adding the debug module.
The buildout system didn't know if this module could effect the mkdir
recipe, so it assumed it could and reinstalled mydata.  If we rerun
the buildout:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Updating data-dir.
    Updating debug.
    File 1 /sample-buildout/mydata/file
    File 2 /sample-buildout/mydata/file/log
    recipe recipes:debug

We can see that mydata was not recreated.

Note that, in this case, we didn't specify a log level, so
we didn't get output about what the buildout was doing.

Section and option names in variable substitutions are only allowed to
contain alphanumeric characters, hyphens, periods and spaces. This
restriction might be relaxed in future releases.


Automatic part selection and ordering
-------------------------------------

When a section with a recipe is referred to, either through variable
substitution or by an initializing recipe, the section is treated as a
part and added to the part list before the referencing part.  For
example, we can leave data-dir out of the parts list:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... log-level = INFO
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... File 1 = ${data-dir:path}/file
    ... File 2 = ${debug:File 1}/log
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mydata
    ... """)


It will still be treated as a part:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Updating data-dir.
    Updating debug.
    File 1 /sample-buildout/mydata/file
    File 2 /sample-buildout/mydata/file/log
    recipe recipes:debug

    &gt;&gt;&gt; cat('.installed.cfg') # doctest: +ELLIPSIS
    [buildout]
    installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
    parts = data-dir debug
    ...

Note that the data-dir part is included *before* the debug part,
because the debug part refers to the data-dir part.  Even if we list
the data-dir part after the debug part, it will be included before:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug data-dir
    ... log-level = INFO
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... File 1 = ${data-dir:path}/file
    ... File 2 = ${debug:File 1}/log
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mydata
    ... """)


It will still be treated as a part:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Updating data-dir.
    Updating debug.
    File 1 /sample-buildout/mydata/file
    File 2 /sample-buildout/mydata/file/log
    recipe recipes:debug

    &gt;&gt;&gt; cat('.installed.cfg') # doctest: +ELLIPSIS
    [buildout]
    installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
    parts = data-dir debug
    ...

Multiple configuration files
----------------------------

A configuration file can "extend" another configuration file.
Options are read from the other configuration file if they aren't
already defined by your configuration file.

The configuration files your file extends can extend
other configuration files.  The same file may be
used more than once although, of course, cycles aren't allowed.

To see how this works, we use an example:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... extends = base.cfg
    ...
    ... [debug]
    ... op = buildout
    ... """)

    &gt;&gt;&gt; write(sample_buildout, 'base.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... op = base
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Uninstalling data-dir.
    Installing debug.
    op buildout
    recipe recipes:debug

The example is pretty trivial, but the pattern it illustrates is
pretty common.  In a more practical example, the base buildout might
represent a product and the extending buildout might be a
customization. 

Here is a more elaborate example. 

    &gt;&gt;&gt; other = tmpdir('other')

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... extends = b1.cfg b2.cfg %(b3)s
    ...
    ... [debug]
    ... op = buildout
    ... """ % dict(b3=os.path.join(other, 'b3.cfg')))

    &gt;&gt;&gt; write(sample_buildout, 'b1.cfg',
    ... """
    ... [buildout]
    ... extends = base.cfg
    ...
    ... [debug]
    ... op1 = b1 1
    ... op2 = b1 2
    ... """)

    &gt;&gt;&gt; write(sample_buildout, 'b2.cfg',
    ... """
    ... [buildout]
    ... extends = base.cfg
    ...
    ... [debug]
    ... op2 = b2 2
    ... op3 = b2 3
    ... """)

    &gt;&gt;&gt; write(other, 'b3.cfg',
    ... """
    ... [buildout]
    ... extends = b3base.cfg
    ...
    ... [debug]
    ... op4 = b3 4
    ... """)

    &gt;&gt;&gt; write(other, 'b3base.cfg',
    ... """
    ... [debug]
    ... op5 = b3base 5
    ... """)

    &gt;&gt;&gt; write(sample_buildout, 'base.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... name = base
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    name base
    op buildout
    op1 b1 1
    op2 b2 2
    op3 b2 3
    op4 b3 4
    op5 b3base 5
    recipe recipes:debug

There are several things to note about this example:

- We can name multiple files in an extends option.

- We can reference files recursively.

- Relative file names in extended options are interpreted relative to
  the directory containing the referencing configuration file.

Loading Configuration from URLs
-------------------------------

Configuration files can be loaded from URLs.  To see how this works,
we'll set up a web server with some configuration files.

    &gt;&gt;&gt; server_data = tmpdir('server_data')

    &gt;&gt;&gt; write(server_data, "r1.cfg",
    ... """
    ... [debug]
    ... op1 = r1 1
    ... op2 = r1 2
    ... """)

    &gt;&gt;&gt; write(server_data, "r2.cfg",
    ... """
    ... [buildout]
    ... extends = r1.cfg
    ... 
    ... [debug]
    ... op2 = r2 2
    ... op3 = r2 3
    ... """)

    &gt;&gt;&gt; server_url = start_server(server_data)

    &gt;&gt;&gt; write('client.cfg', 
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... extends = %(url)s/r2.cfg
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... name = base
    ... """ % dict(url=server_url))


    &gt;&gt;&gt; print system(buildout+ ' -c client.cfg'),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    name base
    op1 r1 1
    op2 r2 2
    op3 r2 3
    recipe recipes:debug

Here we specified a URL for the file we extended.  The file we
downloaded, itself referred to a file on the server using a relative
URL reference.  Relative references are interpreted relative to the
base URL when they appear in configuration files loaded via URL.

We can also specify a URL as the configuration file to be used by a
buildout.  

    &gt;&gt;&gt; os.remove('client.cfg')
    &gt;&gt;&gt; write(server_data, 'remote.cfg', 
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... extends = r2.cfg
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... name = remote
    ... """)

    &gt;&gt;&gt; print system(buildout + ' -c ' + server_url + '/remote.cfg'),
    While:
      Initializing.
    Error: Missing option: buildout:directory

Normally, the buildout directory defaults to directory
containing a configuration file.  This won't work for configuration
files loaded from URLs.  In this case, the buildout directory would
normally be defined on the command line:

    &gt;&gt;&gt; print system(buildout
    ...              + ' -c ' + server_url + '/remote.cfg'
    ...              + ' buildout:directory=' + sample_buildout
    ...              ),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    name remote
    op1 r1 1
    op2 r2 2
    op3 r2 3
    recipe recipes:debug

User defaults
-------------

If the file $HOME/.buildout/default.cfg, exists, it is read before
reading the configuration file.  ($HOME is the value of the HOME
environment variable. The '/' is replaced by the operating system file
delimiter.)

    &gt;&gt;&gt; old_home = os.environ['HOME']
    &gt;&gt;&gt; home = tmpdir('home')
    &gt;&gt;&gt; mkdir(home, '.buildout')
    &gt;&gt;&gt; write(home, '.buildout', 'default.cfg',
    ... """
    ... [debug]
    ... op1 = 1
    ... op7 = 7
    ... """)

    &gt;&gt;&gt; os.environ['HOME'] = home
    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    name base
    op buildout
    op1 b1 1
    op2 b2 2
    op3 b2 3
    op4 b3 4
    op5 b3base 5
    op7 7
    recipe recipes:debug

A buildout command-line argument, -U, can be used to suppress reading
user defaults:

    &gt;&gt;&gt; print system(buildout + ' -U'),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    name base
    op buildout
    op1 b1 1
    op2 b2 2
    op3 b2 3
    op4 b3 4
    op5 b3base 5
    recipe recipes:debug

    &gt;&gt;&gt; os.environ['HOME'] = old_home

Log level
---------

We can control the level of logging by specifying a log level in out
configuration file.  For example, so suppress info messages, we can
set the logging level to WARNING

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... log-level = WARNING
    ... extends = b1.cfg b2.cfg
    ... """)

    &gt;&gt;&gt; print system(buildout),
    name base
    op1 b1 1
    op2 b2 2
    op3 b2 3
    recipe recipes:debug

Uninstall recipes
-----------------

As we've seen, when parts are installed, buildout keeps track of files
and directories that they create. When the parts are uninstalled these
files and directories are deleted.

Sometimes more clean up is needed. For example, a recipe might add a
system service by calling chkconfig --add during installation. Later
during uninstallation, chkconfig --del will need to be called to
remove the system service.

In order to deal with these uninstallation issues, you can register
uninstall recipes. Uninstall recipes are registered using the
'zc.buildout.uninstall' entry point. Parts specify uninstall recipes
using the 'uninstall' option.

In comparison to regular recipes, uninstall recipes are much
simpler. They are simply callable objects that accept the name of the
part to be uninstalled and the part's options dictionary. Uninstall
recipes don't have access to the part itself since it maybe not be
able to be instantiated at uninstallation time.

Here's a recipe that simulates installation of a system service, along
with an uninstall recipe that simulates removing the service.

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'service.py', 
    ... """
    ... class Service:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.buildout = buildout
    ...         self.name = name
    ...         self.options = options
    ...
    ...     def install(self):
    ...         print "chkconfig --add %s" % self.options['script']         
    ...         return ()
    ...
    ...     def update(self):
    ...         pass
    ...
    ...
    ... def uninstall_service(name, options):
    ...     print "chkconfig --del %s" % options['script']
    ... """)

To use these recipes we must register them using entry points. Make
sure to use the same name for the recipe and uninstall recipe. This is
required to let buildout know which uninstall recipe goes with which
recipe.

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... entry_points = (
    ... '''
    ... [zc.buildout]
    ... mkdir = mkdir:Mkdir
    ... debug = debug:Debug
    ... service = service:Service
    ...
    ... [zc.buildout.uninstall]
    ... service = service:uninstall_service
    ... ''')
    ... setup(name="recipes", entry_points=entry_points)
    ... """)

Here's how these recipes could be used in a buildout:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = service
    ...
    ... [service]
    ... recipe = recipes:service
    ... script = /path/to/script
    ... """)

When the buildout is run the service will be installed

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing service.
    chkconfig --add /path/to/script
    &lt;BLANKLINE&gt;

The service has been installed. If the buildout is run again with no
changes, the service shouldn't be changed.

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Updating service.
    &lt;BLANKLINE&gt;

Now we change the service part to trigger uninstallation and
re-installation.

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = service
    ...
    ... [service]
    ... recipe = recipes:service
    ... script = /path/to/a/different/script
    ... """)

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Uninstalling service.
    Running uninstall recipe.
    chkconfig --del /path/to/script
    Installing service.
    chkconfig --add /path/to/a/different/script
    &lt;BLANKLINE&gt;

Now we remove the service part, and add another part.

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... 
    ... [debug]
    ... recipe = recipes:debug
    ... """)

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Uninstalling service.
    Running uninstall recipe.
    chkconfig --del /path/to/a/different/script
    Installing debug.
    recipe recipes:debug
    &lt;BLANKLINE&gt;

Uninstall recipes don't have to take care of removing all the files
and directories created by the part. This is still done automatically,
following the execution of the uninstall recipe. An upshot is that an
uninstallation recipe can access files and directories created by a
recipe before they are deleted.

For example, here's an uninstallation recipe that simulates backing up
a directory before it is deleted. It is designed to work with the
mkdir recipe introduced earlier.
 
    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'backup.py', 
    ... """
    ... import os
    ... def backup_directory(name, options):
    ...     path = options['path']
    ...     size = len(os.listdir(path))
    ...     print "backing up directory %s of size %s" % (path, size) 
    ... """)

It must be registered with the zc.buildout.uninstall entry
point. Notice how it is given the name 'mkdir' to associate it with
the mkdir recipe.

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... entry_points = (
    ... '''
    ... [zc.buildout]
    ... mkdir = mkdir:Mkdir
    ... debug = debug:Debug
    ... service = service:Service
    ...
    ... [zc.buildout.uninstall]
    ... uninstall_service = service:uninstall_service
    ... mkdir = backup:backup_directory
    ... ''')
    ... setup(name="recipes", entry_points=entry_points)
    ... """)

Now we can use it with a mkdir part.

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = dir debug
    ... 
    ... [dir]
    ... recipe = recipes:mkdir
    ... path = my_directory
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... """)

Run the buildout to install the part.

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing dir.
    dir: Creating directory my_directory
    Installing debug.
    recipe recipes:debug
    &lt;BLANKLINE&gt;

Now we remove the part from the configuration file.

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... 
    ... [debug]
    ... recipe = recipes:debug
    ... """)

When the buildout is run the part is removed, and the uninstall recipe
is run before the directory is deleted.

    &gt;&gt;&gt; print system(buildout)
    Develop: '/sample-buildout/recipes'
    Uninstalling dir.
    Running uninstall recipe.
    backing up directory /sample-buildout/my_directory of size 0
    Updating debug.
    recipe recipes:debug
    &lt;BLANKLINE&gt;

Now we will return the registration to normal for the benefit of the
rest of the examples.

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... entry_points = (
    ... '''
    ... [zc.buildout]
    ... mkdir = mkdir:Mkdir
    ... debug = debug:Debug
    ... ''')
    ... setup(name="recipes", entry_points=entry_points)
    ... """)


Command-line usage
------------------

A number of arguments can be given on the buildout command line.  The
command usage is::

  buildout [options and assignments] [command [command arguments]]

The following options are supported:

-h (or --help)
    Print basic usage information.  If this option is used, then all
    other options are ignored.

-c filename
    The -c option can be used to specify a configuration file, rather than
    buildout.cfg in the current directory.  

-v
    Increment the verbosity by 10.  The verbosity is used to adjust
    the logging level.  The verbosity is subtracted from the numeric
    value of the log-level option specified in the configuration file.

-q
    Decrement the verbosity by 10.

-U
    Don't read user-default configuration.

-o
    Run in off-line mode.  This is equivalent to the assignment 
    buildout:offline=true.

-O
    Run in non-off-line mode.  This is equivalent to the assignment 
    buildout:offline=false.  This is the default buildout mode.  The
    -O option would normally be used to override a true offline
    setting in a configuration file.

-n
    Run in newest mode.  This is equivalent to the assignment
    buildout:newest=true.  With this setting, which is the default,
    buildout will try to find the newest versions of distributions
    available that satisfy its requirements.

-N
    Run in non-newest mode.  This is equivalent to the assignment 
    buildout:newest=false.  With this setting, buildout will not seek
    new distributions if installed distributions satisfy it's
    requirements. 

Assignments are of the form::

  section_name:option_name=value

Options and assignments can be given in any order.

Here's an example:

    &gt;&gt;&gt; write(sample_buildout, 'other.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ... installed = .other.cfg
    ... log-level = WARNING
    ...
    ... [debug]
    ... name = other
    ... recipe = recipes:debug
    ... """)

Note that we used the installed buildout option to specify an
alternate file to store information about installed parts.
    
    &gt;&gt;&gt; print system(buildout+' -c other.cfg debug:op1=foo -v'),
    Develop: '/sample-buildout/recipes'
    Installing debug.
    name other
    op1 foo
    recipe recipes:debug

Here we used the -c option to specify an alternate configuration file, 
and the -v option to increase the level of logging from the default,
WARNING.

Options can also be combined in the usual Unix way, as in:
    
    &gt;&gt;&gt; print system(buildout+' -vcother.cfg debug:op1=foo'),
    Develop: '/sample-buildout/recipes'
    Updating debug.
    name other
    op1 foo
    recipe recipes:debug

Here we combined the -v and -c options with the configuration file
name.  Note that the -c option has to be last, because it takes an
argument.

    &gt;&gt;&gt; os.remove(os.path.join(sample_buildout, 'other.cfg'))
    &gt;&gt;&gt; os.remove(os.path.join(sample_buildout, '.other.cfg'))

The most commonly used command is 'install' and it takes a list of
parts to install. if any parts are specified, only those parts are
installed.  To illustrate this, we'll update our configuration and run
the buildout in the usual way:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug d1 d2 d3
    ...
    ... [d1]
    ... recipe = recipes:mkdir
    ... path = d1
    ...
    ... [d2]
    ... recipe = recipes:mkdir
    ... path = d2
    ...
    ... [d3]
    ... recipe = recipes:mkdir
    ... path = d3
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... """)

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling debug.
    Installing debug.
    recipe recipes:debug
    Installing d1.
    d1: Creating directory d1
    Installing d2.
    d2: Creating directory d2
    Installing d3.
    d3: Creating directory d3
    
    &gt;&gt;&gt; ls(sample_buildout)
    -  .installed.cfg
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  d1
    d  d2
    d  d3
    d  develop-eggs
    d  eggs
    d  parts
    d  recipes

    &gt;&gt;&gt; cat(sample_buildout, '.installed.cfg')
    [buildout]
    installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
    parts = debug d1 d2 d3
    &lt;BLANKLINE&gt;
    [debug]
    __buildout_installed__ = 
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    recipe = recipes:debug
    &lt;BLANKLINE&gt;
    [d1]
    __buildout_installed__ = /sample-buildout/d1
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/d1
    recipe = recipes:mkdir
    &lt;BLANKLINE&gt;
    [d2]
    __buildout_installed__ = /sample-buildout/d2
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/d2
    recipe = recipes:mkdir
    &lt;BLANKLINE&gt;
    [d3]
    __buildout_installed__ = /sample-buildout/d3
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/d3
    recipe = recipes:mkdir

Now we'll update our configuration file:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug d2 d3 d4
    ...
    ... [d2]
    ... recipe = recipes:mkdir
    ... path = data2
    ...
    ... [d3]
    ... recipe = recipes:mkdir
    ... path = data3
    ...
    ... [d4]
    ... recipe = recipes:mkdir
    ... path = ${d2:path}-extra
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... x = 1
    ... """)

and run the buildout specifying just d3 and d4:

    &gt;&gt;&gt; print system(buildout+' install d3 d4'),
    Develop: '/sample-buildout/recipes'
    Uninstalling d3.
    Installing d3.
    d3: Creating directory data3
    Installing d4.
    d4: Creating directory data2-extra
    
    &gt;&gt;&gt; ls(sample_buildout)
    -  .installed.cfg
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  d1
    d  d2
    d  data2-extra
    d  data3
    d  develop-eggs
    d  eggs
    d  parts
    d  recipes
    
Only the d3 and d4 recipes ran.  d3 was removed and data3 and data2-extra
were created.

The .installed.cfg is only updated for the recipes that ran:

    &gt;&gt;&gt; cat(sample_buildout, '.installed.cfg')
    [buildout]
    installed_develop_eggs = /sample-buildout/develop-eggs/recipes.egg-link
    parts = debug d1 d2 d3 d4
    &lt;BLANKLINE&gt;
    [debug]
    __buildout_installed__ = 
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    recipe = recipes:debug
    &lt;BLANKLINE&gt;
    [d1]
    __buildout_installed__ = /sample-buildout/d1
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/d1
    recipe = recipes:mkdir
    &lt;BLANKLINE&gt;
    [d2]
    __buildout_installed__ = /sample-buildout/d2
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/d2
    recipe = recipes:mkdir
    &lt;BLANKLINE&gt;
    [d3]
    __buildout_installed__ = /sample-buildout/data3
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/data3
    recipe = recipes:mkdir
    &lt;BLANKLINE&gt;
    [d4]
    __buildout_installed__ = /sample-buildout/data2-extra
    __buildout_signature__ = recipes-PiIFiO8ny5yNZ1S3JfT0xg==
    path = /sample-buildout/data2-extra
    recipe = recipes:mkdir

Note that the installed data for debug, d1, and d2 haven't changed,
because we didn't install those parts and that the d1 and d2
directories are still there.

Now, if we run the buildout without the install command:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Uninstalling d2.
    Uninstalling d1.
    Uninstalling debug.
    Installing debug.
    recipe recipes:debug
    x 1
    Installing d2.
    d2: Creating directory data2
    Updating d3.
    Updating d4.

We see the output of the debug recipe and that data2 was created.  We
also see that d1 and d2 have gone away:

    &gt;&gt;&gt; ls(sample_buildout)
    -  .installed.cfg
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  data2
    d  data2-extra
    d  data3
    d  develop-eggs
    d  eggs
    d  parts
    d  recipes

Alternate directory and file locations
--------------------------------------

The buildout normally puts the bin, eggs, and parts directories in the
directory in the directory containing the configuration file. You can
provide alternate locations, and even names for these directories.

    &gt;&gt;&gt; alt = tmpdir('sample-alt')

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = 
    ... develop-eggs-directory = %(developbasket)s
    ... eggs-directory = %(basket)s
    ... bin-directory = %(scripts)s
    ... parts-directory = %(work)s
    ... """ % dict(
    ...    developbasket = os.path.join(alt, 'developbasket'),
    ...    basket = os.path.join(alt, 'basket'),
    ...    scripts = os.path.join(alt, 'scripts'),
    ...    work = os.path.join(alt, 'work'),
    ... ))

    &gt;&gt;&gt; print system(buildout),
    Creating directory '/sample-alt/scripts'.
    Creating directory '/sample-alt/work'.
    Creating directory '/sample-alt/basket'.
    Creating directory '/sample-alt/developbasket'.
    Develop: '/sample-buildout/recipes'
    Uninstalling d4.
    Uninstalling d3.
    Uninstalling d2.
    Uninstalling debug.

    &gt;&gt;&gt; ls(alt)
    d  basket
    d  developbasket
    d  scripts
    d  work

    &gt;&gt;&gt; ls(alt, 'developbasket')    
    -  recipes.egg-link

You can also specify an alternate buildout directory:

    &gt;&gt;&gt; rmdir(alt)
    &gt;&gt;&gt; alt = tmpdir('sample-alt')

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... directory = %(alt)s
    ... develop = %(recipes)s
    ... parts = 
    ... """ % dict(
    ...    alt=alt,
    ...    recipes=os.path.join(sample_buildout, 'recipes'),
    ...    ))
 
    &gt;&gt;&gt; print system(buildout),
    Creating directory '/sample-alt/bin'.
    Creating directory '/sample-alt/parts'.
    Creating directory '/sample-alt/eggs'.
    Creating directory '/sample-alt/develop-eggs'.
    Develop: '/sample-buildout/recipes'

    &gt;&gt;&gt; ls(alt)
    -  .installed.cfg
    d  bin
    d  develop-eggs
    d  eggs
    d  parts

    &gt;&gt;&gt; ls(alt, 'develop-eggs')    
    -  recipes.egg-link

Logging control
---------------

Three buildout options are used to control logging:

log-level 
   specifies the log level

verbosity 
   adjusts the log level

log-format
   allows an alternate logging for mat to be specified

We've already seen the log level and verbosity.  Let's look at an example
of changing the format:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts =
    ... log-level = 25
    ... verbosity = 5
    ... log-format = %(levelname)s %(message)s
    ... """)
 
Here, we've changed the format to include the log-level name, rather
than the logger name.

We've also illustrated, with a contrived example, that the log level
can be a numeric value and that the verbosity can be specified in the
configuration file.  Because the verbosity is subtracted from the log
level, we get a final log level of 20, which is the INFO level.

    &gt;&gt;&gt; print system(buildout),
    INFO Develop: '/sample-buildout/recipes'

Predefined buildout options
---------------------------

Buildouts have a number of predefined options that recipes can use
and that users can override in their configuration files.  To see
these, we'll run a minimal buildout configuration with a debug logging
level.  One of the features of debug logging is that the configuration
database is shown.
         
    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... parts =
    ... """)

    &gt;&gt;&gt; print system(buildout+' -vv'),
    Installing 'zc.buildout', 'setuptools'.
    We have a develop egg: zc.buildout 1.0.0.
    We have the best distribution that satisfies 'setuptools'.
    Picked: setuptools = 0.6
    &lt;BLANKLINE&gt;
    Configuration data:
    [buildout]
    bin-directory = /sample-buildout/bin
    develop-eggs-directory = /sample-buildout/develop-eggs
    directory = /sample-buildout
    eggs-directory = /sample-buildout/eggs
    executable = /usr/local/bin/python2.3
    installed = /sample-buildout/.installed.cfg
    log-format = 
    log-level = INFO
    newest = true
    offline = false
    parts = 
    parts-directory = /sample-buildout/parts
    python = buildout
    verbosity = 20
    &lt;BLANKLINE&gt;
 
All of these options can be overridden by configuration files or by
command-line assignments.  We've discussed most of these options
already, but let's review them and touch on some we haven't discussed:

bin-directory
   The directory path where scripts are written.  This can be a
   relative path, which is interpreted relative to the directory
   option.

develop-eggs-directory
   The directory path where development egg links are created for software
   being created in the local project.  This can be a relative path,
   which is interpreted relative to the directory option.

directory
   The buildout directory.  This is the base for other buildout file
   and directory locations, when relative locations are used.

eggs-directory
   The directory path where downloaded eggs are put.  It is common to share
   this directory across buildouts. Eggs in this directory should
   *never* be modified.  This can be a relative path, which is
   interpreted relative to the directory option.

executable
   The Python executable used to run the buildout.  See the python
   option below.

installed
   The file path where information about the results of the previous
   buildout run is written.  This can be a relative path, which is
   interpreted relative to the directory option.  This file provides
   an inventory of installed parts with information needed to decide
   which if any parts need to be uninstalled.

log-format
   The format used for logging messages.

log-level
   The log level before verbosity adjustment

parts
   A white space separated list of parts to be installed.

parts-directory
   A working directory that parts can used to store data.

python
   The name of a section containing information about the default
   Python interpreter.  Recipes that need a installation
   typically have options to tell them which Python installation to
   use.  By convention, if a section-specific option isn't used, the
   option is looked for in the buildout section.  The option must
   point to a section with an executable option giving the path to a
   Python executable.  By default, the buildout section defines the
   default Python as the Python used to run the buildout.

verbosity
   A log-level adjustment.  Typically, this is set via the -q and -v
   command-line options.


Creating new buildouts and bootstrapping
----------------------------------------

If zc.buildout is installed, you can use it to create a new buildout
with it's own local copies of zc.buildout and setuptools and with
local buildout scripts. 

    &gt;&gt;&gt; sample_bootstrapped = tmpdir('sample-bootstrapped')

    &gt;&gt;&gt; print system(buildout
    ...              +' -c'+os.path.join(sample_bootstrapped, 'setup.cfg')
    ...              +' init'),
    Creating '/sample-bootstrapped/setup.cfg'.
    Creating directory '/sample-bootstrapped/bin'.
    Creating directory '/sample-bootstrapped/parts'.
    Creating directory '/sample-bootstrapped/eggs'.
    Creating directory '/sample-bootstrapped/develop-eggs'.
    Generated script '/sample-bootstrapped/bin/buildout'.

Note that a basic setup.cfg was created for us.

    &gt;&gt;&gt; ls(sample_bootstrapped)
    d  bin
    d  develop-eggs
    d  eggs
    d  parts
    -  setup.cfg

    &gt;&gt;&gt; ls(sample_bootstrapped, 'bin')
    -  buildout

    &gt;&gt;&gt; _ = (ls(sample_bootstrapped, 'eggs'),
    ...      ls(sample_bootstrapped, 'develop-eggs'))
    -  setuptools-0.6-py2.3.egg
    -  zc.buildout-1.0-py2.3.egg

(We list both the eggs and develop-eggs directories because the
buildout or setuptools egg could be installed in the develop-eggs
directory if the original buildout had develop eggs for either
buildout or setuptools.)

Note that the buildout script was installed but not run.  To run
the buildout, we'd have to run the installed buildout script.

If we have an existing buildout that already has a buildout.cfg, we'll
normally use the bootstrap command instead of init.  It will complain
if there isn't a configuration file:

     &gt;&gt;&gt; sample_bootstrapped2 = tmpdir('sample-bootstrapped2')

     &gt;&gt;&gt; print system(buildout
     ...              +' -c'+os.path.join(sample_bootstrapped2, 'setup.cfg')
     ...              +' bootstrap'),
     While:
       Initializing.
     Error: Couldn't open /sample-bootstrapped2/setup.cfg

     &gt;&gt;&gt; write(sample_bootstrapped2, 'setup.cfg',
     ... """
     ... [buildout]
     ... parts =
     ... """)

    &gt;&gt;&gt; print system(buildout
    ...              +' -c'+os.path.join(sample_bootstrapped2, 'setup.cfg')
    ...              +' bootstrap'),
    Creating directory '/sample-bootstrapped2/bin'.
    Creating directory '/sample-bootstrapped2/parts'.
    Creating directory '/sample-bootstrapped2/eggs'.
    Creating directory '/sample-bootstrapped2/develop-eggs'.
    Generated script '/sample-bootstrapped2/bin/buildout'.


Newest and Offline Modes
------------------------

By default buildout and recipes will try to find the newest versions
of distributions needed to satisfy requirements.  This can be very
time consuming, especially when incrementally working on setting up a
buildout or working on a recipe.  The buildout newest option can be
used to to suppress this.  If the newest option is set to false, then
new distributions won't be sought if an installed distribution meets
requirements.  The newest option can be set to false using the -N
command-line option.

The offline option goes a bit further.  If the buildout offline option
is given a value of "true", the buildout and recipes that are aware of
the option will avoid doing network access.  This is handy when
running the buildout when not connected to the internet.  It also
makes buildouts run much faster. This option is typically set using
the buildout -o option.

Preferring Final Releases
-------------------------

Currently, when searching for new releases, the newest available
release is used.  This isn't usually ideal, as you may get a
development release or alpha releases not ready to be widely used.
You can request that final releases be preferred using the prefer
final option in the buildout section::

  [buildout]
  ...
  prefer-final = true

When the prefer-final option is set to true, then when searching for
new releases, final releases are preferred.  If there are final
releases that satisfy distribution requirements, then those releases
are used even if newer non-final releases are available.  The buildout
prefer-final option can be used to override this behavior.

In buildout version 2, final releases will be preferred by default.
You will then need to use a false value for prefer-final to get the
newest releases.

Dependency links
----------------

By default buildout will obey the setuptools dependency_links metadata
when it looks for dependencies. This behavior can be controlled with
the use-dependency-links buildout option::

  [buildout]
  ...
  use-dependency-links = false

The option defaults to true. If you set it to false, then dependency
links are only looked for in the locations specified by find-links.

Controlling the installation database
-------------------------------------

The buildout installed option is used to specify the file used to save
information on installed parts.  This option is initialized to
".installed.cfg", but it can be overridden in the configuration file
or on the command line:

    &gt;&gt;&gt; write('buildout.cfg', 
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = debug
    ...
    ... [debug]
    ... recipe = recipes:debug
    ... """)

    &gt;&gt;&gt; print system(buildout+' buildout:installed=inst.cfg'),
    Develop: '/sample-buildout/recipes'
    Installing debug.
    recipe recipes:debug

    &gt;&gt;&gt; ls(sample_buildout)
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    -  inst.cfg
    d  parts
    d  recipes

The installation database can be disabled by supplying an empty
buildout installed option:

    &gt;&gt;&gt; os.remove('inst.cfg')
    &gt;&gt;&gt; print system(buildout+' buildout:installed='),
    Develop: '/sample-buildout/recipes'
    Installing debug.
    recipe recipes:debug

    &gt;&gt;&gt; ls(sample_buildout)
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    d  parts
    d  recipes


Note that there will be no installation database if there are no
parts:

    &gt;&gt;&gt; write('buildout.cfg', 
    ... """
    ... [buildout]
    ... parts =
    ... """)

    &gt;&gt;&gt; print system(buildout+' buildout:installed=inst.cfg'),

    &gt;&gt;&gt; ls(sample_buildout)
    -  b1.cfg
    -  b2.cfg
    -  base.cfg
    d  bin
    -  buildout.cfg
    d  develop-eggs
    d  eggs
    d  parts
    d  recipes

Extensions
----------

An **experimental** feature allows code to be loaded and run after
configuration files have been read but before the buildout has begun
any processing.  The intent is to allow special plugins such as
urllib2 request handlers to be loaded.

To load an extension, we use the extensions option and list one or
more distribution requirements, on separate lines.  The distributions
named will be loaded and any zc.buildout.extensions entry points found
will be called with the buildout as an argument.

Let's create a sample extension in our sample buildout created in the
previous section:

    &gt;&gt;&gt; mkdir(sample_bootstrapped, 'demo')

    &gt;&gt;&gt; write(sample_bootstrapped, 'demo', 'demo.py', 
    ... """
    ... def ext(buildout):
    ...     print 'ext', list(buildout)
    ... """)

    &gt;&gt;&gt; write(sample_bootstrapped, 'demo', 'setup.py',
    ... """
    ... from setuptools import setup
    ... 
    ... setup(
    ...     name = "demo",
    ...     entry_points = {'zc.buildout.extension': ['ext = demo:ext']},
    ...     )
    ... """)

Our extension just prints out the word 'demo', and lists the sections
found in the buildout passed to it.

We'll update our buildout.cfg to list the demo directory as a develop
egg to be built:

    &gt;&gt;&gt; write(sample_bootstrapped, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = demo
    ... parts =
    ... """)

    &gt;&gt;&gt; os.chdir(sample_bootstrapped)
    &gt;&gt;&gt; print system(os.path.join(sample_bootstrapped, 'bin', 'buildout')),
    Develop: '/sample-bootstrapped/demo'

Now we can add the extensions option.  We were a bit tricky and ran
the buildout once with the demo develop egg defined but without the
extension option.  This is because extensions are loaded before the
buildout creates develop eggs. We needed to use a separate buildout
run to create the develop egg.  Normally, when eggs are loaded from
the network, we wouldn't need to do anything special.

    &gt;&gt;&gt; write(sample_bootstrapped, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = demo
    ... extensions = demo
    ... parts =
    ... """)
   
We see that our extension is loaded and executed:

    &gt;&gt;&gt; print system(os.path.join(sample_bootstrapped, 'bin', 'buildout')),
    ext ['buildout']
    Develop: '/sample-bootstrapped/demo'



.. [#future_recipe_methods] In the future, additional methods may be
       added. Older recipes with fewer methods will still be
       supported.

.. [#packaging_info] If we wanted to create a distribution from this
       package, we would need specify much more information.  See the
       `setuptools documentation
       &lt;http://peak.telecommunity.com/DevCenter/setuptools&gt;`_.

Repeatable buildouts: controlling eggs used
===========================================

One of the goals of zc.buildout is to provide enough control to make
buildouts repeatable.  It should be possible to check the buildout
configuration files for a project into a version control system and
later use the checked in files to get the same buildout, subject to
changes in the environment outside the buildout.

An advantage of using Python eggs is that depenencies of eggs used are
automatically determined and used.  The automatic inclusion of
depenent distributions is at odds with the goal of repeatable
buildouts.

To support repeatable buildouts, a versions section can be created
with options for each distribution name whos version is to be fixed.
The section can then be specified via the buildout versions option.

To see how this works, we'll create two versions of a recipe egg:

    &gt;&gt;&gt; mkdir('recipe')
    &gt;&gt;&gt; write('recipe', 'recipe.py',
    ... '''
    ... class Recipe:
    ...     def __init__(*a): pass
    ...     def install(self):
    ...         print 'recipe v1'
    ...         return ()
    ...     update = install
    ... ''')

    &gt;&gt;&gt; write('recipe', 'setup.py',
    ... '''
    ... from setuptools import setup
    ... setup(name='spam', version='1', py_modules=['recipe'],
    ...       entry_points={'zc.buildout': ['default = recipe:Recipe']},
    ...       )
    ... ''')

    &gt;&gt;&gt; write('recipe', 'README', '')

    &gt;&gt;&gt; print system(buildout+' setup recipe bdist_egg'), # doctest: +ELLIPSIS
    Running setup script 'recipe/setup.py'.
    ...

    &gt;&gt;&gt; rmdir('recipe', 'build')

    &gt;&gt;&gt; write('recipe', 'recipe.py',
    ... '''
    ... class Recipe:
    ...     def __init__(*a): pass
    ...     def install(self):
    ...         print 'recipe v2'
    ...         return ()
    ...     update = install
    ... ''')

    &gt;&gt;&gt; write('recipe', 'setup.py',
    ... '''
    ... from setuptools import setup
    ... setup(name='spam', version='2', py_modules=['recipe'],
    ...       entry_points={'zc.buildout': ['default = recipe:Recipe']},
    ...       )
    ... ''')


    &gt;&gt;&gt; print system(buildout+' setup recipe bdist_egg'), # doctest: +ELLIPSIS
    Running setup script 'recipe/setup.py'.
    ...

and we'll configure a buildout to use it:

    &gt;&gt;&gt; write('buildout.cfg',
    ... '''
    ... [buildout]
    ... parts = foo
    ... find-links = %s
    ...
    ... [foo]
    ... recipe = spam
    ... ''' % join('recipe', 'dist'))

If we run the buildout, it will use version 2:

    &gt;&gt;&gt; print system(buildout),
    Getting distribution for 'spam'.
    Got spam 2.
    Installing foo.
    recipe v2

We can specify a versions section that lists our recipe and name it in
the buildout section:

    &gt;&gt;&gt; write('buildout.cfg',
    ... '''
    ... [buildout]
    ... parts = foo
    ... find-links = %s
    ... versions = release-1
    ...
    ... [release-1]
    ... spam = 1
    ... eggs = 2.2
    ...
    ... [foo]
    ... recipe = spam
    ... ''' % join('recipe', 'dist'))

Here we created a release-1 section listing the version 1 for the spam
distribution.  We told the buildout to use it by specifying release-1
as in the versions option.

Now, if we run the buildout, we'll use version 1 of the spam recipe:

    &gt;&gt;&gt; print system(buildout),
    Getting distribution for 'spam==1'.
    Got spam 1.
    Uninstalling foo.
    Installing foo.
    recipe v1

Running the buildout in verbose mode will help us get information
about versions used. If we run the buildout in verbose mode without
specifying a versions section:

    &gt;&gt;&gt; print system(buildout+' buildout:versions= -v'), # doctest: +ELLIPSIS
    Installing 'zc.buildout', 'setuptools'.
    We have a develop egg: zc.buildout 1.0.0.
    We have the best distribution that satisfies 'setuptools'.
    Picked: setuptools = 0.6
    Installing 'spam'.
    We have the best distribution that satisfies 'spam'.
    Picked: spam = 2.
    Uninstalling foo.
    Installing foo.
    recipe v2

We'll get output that includes lines that tell us what versions
buildout chose a for us, like::

    zc.buildout.easy_install.picked: spam = 2

This allows us to discover versions that are picked dynamically, so
that we can fix them in a versions section.

If we run the buildout with the versions section:

    &gt;&gt;&gt; print system(buildout+' -v'), # doctest: +ELLIPSIS
    Installing 'zc.buildout', 'setuptools'.
    We have a develop egg: zc.buildout 1.0.0.
    We have the best distribution that satisfies 'setuptools'.
    Picked: setuptools = 0.6
    Installing 'spam'.
    We have the distribution that satisfies 'spam==1'.
    Uninstalling foo.
    Installing foo.
    recipe v1

We won't get output for the spam distribution, which we didn't pick,
but we will get output for setuptools, which we didn't specify
versions for.

You can request buildout to generate an error if it picks any
versions:

    &gt;&gt;&gt; write('buildout.cfg',
    ... '''
    ... [buildout]
    ... parts = foo
    ... find-links = %s
    ... versions = release-1
    ... allow-picked-versions = false
    ...
    ... [release-1]
    ... spam = 1
    ... eggs = 2.2
    ...
    ... [foo]
    ... recipe = spam
    ... ''' % join('recipe', 'dist'))

Using a download cache
======================

Normally, when distributions are installed, if any processing is
needed, they are downloaded from the internet to a temporary directory
and then installed from there.  A download cache can be used to avoid
the download step.  This can be useful to reduce network access and to
create source distributions of an entire buildout.

The buildout download-cache option can be used to specify a directory
to be used as a download cache.

In this example, we'll create a directory to hold the cache:

    &gt;&gt;&gt; cache = tmpdir('cache')

And set up a buildout that downloads some eggs:

    &gt;&gt;&gt; write('buildout.cfg',
    ... '''
    ... [buildout]
    ... parts = eggs
    ... download-cache = %(cache)s
    ... find-links = %(link_server)s
    ...
    ... [eggs]
    ... recipe = zc.recipe.egg
    ... eggs = demo ==0.2
    ... ''' % globals())

We specified a link server that has some distributions available for
download:

    &gt;&gt;&gt; print get(link_server),
    &lt;html&gt;&lt;body&gt;
    &lt;a href="demo-0.1-py2.4.egg"&gt;demo-0.1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.2-py2.4.egg"&gt;demo-0.2-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.3-py2.4.egg"&gt;demo-0.3-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.4c1-py2.4.egg"&gt;demo-0.4c1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.0.zip"&gt;demoneeded-1.0.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.1.zip"&gt;demoneeded-1.1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.2c1.zip"&gt;demoneeded-1.2c1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="extdemo-1.4.zip"&gt;extdemo-1.4.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="index/"&gt;index/&lt;/a&gt;&lt;br&gt;
    &lt;a href="other-1.0-py2.4.egg"&gt;other-1.0-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;/body&gt;&lt;/html&gt;
    

We'll enable logging on the link server so we can see what's going on:

    &gt;&gt;&gt; get(link_server+'enable_server_logging')
    GET 200 /enable_server_logging
    ''

We also specified a download cache.

If we run the buildout, we'll see the eggs installed from the link
server as usual:

    &gt;&gt;&gt; print system(buildout),
    GET 200 /
    GET 200 /demo-0.2-py2.4.egg
    GET 200 /demoneeded-1.2c1.zip
    Installing eggs.
    Getting distribution for 'demo==0.2'.
    Got demo 0.2.
    Getting distribution for 'demoneeded'.
    Got demoneeded 1.2c1.
    Generated script '/sample-buildout/bin/demo'.

We'll also get the download cache populated.  The buildout doesn't put
files in the cache directly.  It creates an intermediate directory,
dist:


    &gt;&gt;&gt; ls(cache)
    d  dist

    &gt;&gt;&gt; ls(cache, 'dist')
    -  demo-0.2-py2.4.egg
    -  demoneeded-1.2c1.zip

If we remove the installed eggs from eggs directory and re-run the buildout:

    &gt;&gt;&gt; import os
    &gt;&gt;&gt; for  f in os.listdir('eggs'):
    ...     if f.startswith('demo'):
    ...         remove('eggs', f)
   
    &gt;&gt;&gt; print system(buildout),
    GET 200 /
    Updating eggs.
    Getting distribution for 'demo==0.2'.
    Got demo 0.2.
    Getting distribution for 'demoneeded'.
    Got demoneeded 1.2c1.

We see that the distributions aren't downloaded, because they're
downloaded from the cache.

Installing solely from a download cache
---------------------------------------

A download cache can be used as the basis of application source
releases.  In an application source release, we want to distribute an
application that can be built without making any network accesses.  In
this case, we distribute a buildout with download cache and tell the
buildout to install from the download cache only, without making
network accesses.  The buildout install-from-cache option can be used
to signal that packages should be installed only from the download
cache.

Let's remove our installed eggs and run the buildout with the
install-from-cache option set to true:

    &gt;&gt;&gt; for  f in os.listdir('eggs'):
    ...     if f.startswith('demo'):
    ...         remove('eggs', f)

    &gt;&gt;&gt; write('buildout.cfg',
    ... '''
    ... [buildout]
    ... parts = eggs
    ... download-cache = %(cache)s
    ... install-from-cache = true
    ... find-links = %(link_server)s
    ...
    ... [eggs]
    ... recipe = zc.recipe.egg
    ... eggs = demo
    ... ''' % globals())

    &gt;&gt;&gt; print system(buildout),
    Uninstalling eggs.
    Installing eggs.
    Getting distribution for 'demo'.
    Got demo 0.2.
    Getting distribution for 'demoneeded'.
    Got demoneeded 1.2c1.
    Generated script '/sample-buildout/bin/demo'.

Using zc.buildout to run setup scripts
======================================

zc buildout has a convenience command for running setup scripts.  Why?
There are two reasons.  If a setup script doesn't import setuptools,
you can't use aby setuptools-provided commands, like bdist_egg.  When
buildut runs a setup script, it arranges to import setuptools before
running the script so setuptools-provided commands are available.

If you use a squeaky-clean Python to do your development, the a setup
script that would import setuptools because setuptools isn't in the
path.  Because buildout requires setuptools and knows where it has
installed a setuptools egg, it add the setuptools egg to the Python
path before running the script.  To run a setup script, use the
buildout setup command, passing the name of a secript or a directory
containing a setup script and arguments to the script.  Let's look at
an example:

    &gt;&gt;&gt; mkdir('test')
    &gt;&gt;&gt; cd('test')
    &gt;&gt;&gt; write('setup.py',
    ... '''
    ... from distutils.core import setup
    ... setup(name='sample')
    ... ''')

We've created a super simple (stupid) setup script.  Note that it
doesn't import setuptools.  Let's try running it to create an egg.
We'll use the buildout script from our sample buildout:

    &gt;&gt;&gt; print system(buildout+' setup'),
    Error: The setup command requires the path to a setup script or 
    directory containing a setup script, and it's arguments.

Oops, we forgot to give the name of the setup script:

    &gt;&gt;&gt; print system(buildout+' setup setup.py bdist_egg'), # doctest: +ELLIPSIS
    Running setup script 'setup.py'.
    ...

    &gt;&gt;&gt; ls('dist')
    -  sample-0.0.0-py2.5.egg

Note that we can specify a directory name.  This is often shorter and
preferred by the lazy :)

    &gt;&gt;&gt; print system(buildout+' setup . bdist_egg'), # doctest: +ELLIPSIS
    Running setup script './setup.py'.
    ...

Automatic Buildout Updates
==========================

When a buildout is run, one of the first steps performed is to check
for updates to either zc.buildout or setuptools.  To demonstrate this,
we've creates some "new releases" of buildout and setuptools in a
new_releases folder:

    &gt;&gt;&gt; ls(new_releases)
    d  setuptools
    -  setuptools-99.99-py2.4.egg
    d  zc.buildout
    -  zc.buildout-99.99-py2.4.egg

Let's update the sample buildout.cfg to look in this area:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... find-links = %(new_releases)s
    ... index = %(new_releases)s
    ... parts = show-versions
    ... develop = showversions
    ... 
    ... [show-versions]
    ... recipe = showversions
    ... """ % dict(new_releases=new_releases))

We'll also include a recipe that echos the versions of setuptools and
zc.buildout used:

    &gt;&gt;&gt; mkdir(sample_buildout, 'showversions')

    &gt;&gt;&gt; write(sample_buildout, 'showversions', 'showversions.py', 
    ... """
    ... import pkg_resources
    ...
    ... class Recipe:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         pass
    ...
    ...     def install(self):
    ...         for project in 'zc.buildout', 'setuptools':
    ...             req = pkg_resources.Requirement.parse(project)
    ...             print project, pkg_resources.working_set.find(req).version
    ...         return ()
    ...     update = install
    ... """)


    &gt;&gt;&gt; write(sample_buildout, 'showversions', 'setup.py',
    ... """
    ... from setuptools import setup
    ... 
    ... setup(
    ...     name = "showversions",
    ...     entry_points = {'zc.buildout': ['default = showversions:Recipe']},
    ...     )
    ... """)


Now if we run the buildout, the buildout will upgrade itself to the
new versions found in new releases:

    &gt;&gt;&gt; print system(buildout),
    Getting distribution for 'zc.buildout'.
    Got zc.buildout 99.99.
    Getting distribution for 'setuptools'.
    Got setuptools 99.99.
    Upgraded:
      zc.buildout version 99.99,
      setuptools version 99.99;
    restarting.
    Generated script '/sample-buildout/bin/buildout'.
    Develop: '/sample-buildout/showversions'
    Installing show-versions.
    zc.buildout 99.99
    setuptools 99.99

Our buildout script has been updated to use the new eggs:

    &gt;&gt;&gt; cat(sample_buildout, 'bin', 'buildout') 
    #!/usr/local/bin/python2.4
    &lt;BLANKLINE&gt;
    import sys
    sys.path[0:0] = [
      '/sample-buildout/eggs/zc.buildout-99.99-py2.4.egg',
      '/sample-buildout/eggs/setuptools-99.99-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    import zc.buildout.buildout
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        zc.buildout.buildout.main()

There are a number of cases in which the updates don't happen.
Let's recreate the sample buildout. One case is the one in which we
specify versions of zc.buildout and setuptools for which the don't
match. If we update out configuration file to specify an older
version:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... find-links = %(new_releases)s
    ... index = %(new_releases)s
    ... parts = show-versions
    ... develop = showversions
    ... zc.buildout-version = &lt; 99
    ... setuptools-version = &lt; 99
    ... 
    ... [show-versions]
    ... recipe = showversions
    ... """ % dict(new_releases=new_releases))

We'll actually "upgrade" to an earlier version.

    &gt;&gt;&gt; print system(buildout),
    Upgraded:
      zc.buildout version 1.0.0,
      setuptools version 0.6;
    restarting.
    Generated script '/sample-buildout/bin/buildout'.
    Develop: '/sample-buildout/showversions'
    Updating show-versions.
    zc.buildout 1.0.0
    setuptools 0.6

We won't upgrade in offline mode:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... find-links = %(new_releases)s
    ... index = %(new_releases)s
    ... parts = show-versions
    ... develop = showversions
    ... 
    ... [show-versions]
    ... recipe = showversions
    ... """ % dict(new_releases=new_releases))

    &gt;&gt;&gt; print system(buildout+' -o'),
    Develop: '/sample-buildout/showversions'
    Updating show-versions.
    zc.buildout 1.0.0
    setuptools 0.6

Or in non-newest mode:

    &gt;&gt;&gt; print system(buildout+' -N'),
    Develop: '/sample-buildout/showversions'
    Updating show-versions.
    zc.buildout 1.0.0
    setuptools 0.6

We also won't upgrade if the buildout script bing run isn't in the
buildouts bin directory.  To see this we'll create a new buildout
directory:

    &gt;&gt;&gt; sample_buildout2 = tmpdir('sample_buildout2')
    &gt;&gt;&gt; write(sample_buildout2, 'buildout.cfg',
    ... """
    ... [buildout]
    ... find-links = %(new_releases)s
    ... index = %(new_releases)s
    ... parts = 
    ... """ % dict(new_releases=new_releases))
    
    &gt;&gt;&gt; cd(sample_buildout2)
    &gt;&gt;&gt; print system(buildout),
    Creating directory '/sample_buildout2/bin'.
    Creating directory '/sample_buildout2/parts'.
    Creating directory '/sample_buildout2/eggs'.
    Creating directory '/sample_buildout2/develop-eggs'.
    Getting distribution for 'zc.buildout'.
    Got zc.buildout 99.99.
    Getting distribution for 'setuptools'.
    Got setuptools 99.99.
    Not upgrading because not running a local buildout command.

    &gt;&gt;&gt; ls('bin')

Debugging buildouts
===================

Buildouts can be pretty complex.  When things go wrong, it isn't
always obvious why.  Errors can occur due to problems in user input or
due to bugs in zc.buildout or recipes.  When an error occurs, Python's
post-mortem debugger can be used to inspect the state of the buildout
or recipe code were there error occured.  To enable this, use the -D
option to the buildout.  Let's create a recipe that has a bug:

    &gt;&gt;&gt; mkdir(sample_buildout, 'recipes')

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'mkdir.py', 
    ... """
    ... import os, zc.buildout
    ...
    ... class Mkdir:
    ...
    ...     def __init__(self, buildout, name, options):
    ...         self.name, self.options = name, options
    ...         options['path'] = os.path.join(
    ...                               buildout['buildout']['directory'],
    ...                               options['path'],
    ...                               )
    ...
    ...     def install(self):
    ...         directory = self.options['directory']
    ...         os.mkdir(directory)
    ...         return directory
    ...
    ...     def update(self):
    ...         pass
    ... """)

    &gt;&gt;&gt; write(sample_buildout, 'recipes', 'setup.py',
    ... """
    ... from setuptools import setup
    ... 
    ... setup(name = "recipes",
    ...       entry_points = {'zc.buildout': ['mkdir = mkdir:Mkdir']},
    ...       )
    ... """)

And create a buildout that uses it:

    &gt;&gt;&gt; write(sample_buildout, 'buildout.cfg',
    ... """
    ... [buildout]
    ... develop = recipes
    ... parts = data-dir
    ...
    ... [data-dir]
    ... recipe = recipes:mkdir
    ... path = mystuff
    ... """)

If we run the buildout, we'll get an error:

    &gt;&gt;&gt; print system(buildout),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    While:
      Installing data-dir.
    Error: Missing option: data-dir:directory


If we want to debug the error, we can add the -D option. Here's we'll
supply some input:

    &gt;&gt;&gt; print system(buildout+" -D", """\
    ... up
    ... p self.options.keys()
    ... q
    ... """),
    Develop: '/sample-buildout/recipes'
    Installing data-dir.
    &gt; /zc/buildout/buildout.py(925)__getitem__()
    -&gt; raise MissingOption("Missing option: %s:%s" % (self.name, key))
    (Pdb) &gt; /sample-buildout/recipes/mkdir.py(14)install()
    -&gt; directory = self.options['directory']
    (Pdb) ['path', 'recipe']
    (Pdb) While:
      Installing data-dir.
    Traceback (most recent call last):
      File "/zc/buildout/buildout.py", line 1352, in main
        getattr(buildout, command)(args)
      File "/zc/buildout/buildout.py", line 383, in install
        installed_files = self[part]._call(recipe.install)
      File "/zc/buildout/buildout.py", line 961, in _call
        return f()
      File "/sample-buildout/recipes/mkdir.py", line 14, in install
        directory = self.options['directory']
      File "/zc/buildout/buildout.py", line 925, in __getitem__
        raise MissingOption("Missing option: %s:%s" % (self.name, key))
    MissingOption: Missing option: data-dir:directory
    &lt;BLANKLINE&gt;
    Starting pdb:

Testing Support
===============

The zc.buildout.testing module provides an API that can be used when
writing recipe tests.  This API is documented below.  Many examples of
using this API can be found in the zc.buildout, zc.recipe.egg, and
zc.recipe.testrunner tests.

zc.buildout.testing.buildoutSetUp(test)
---------------------------------------

The buildoutSetup function can be used as a doctest setup function.
It creates a sample buildout that can be used by tests, changing the
current working directory to the sample_buildout. It also adds a
number of names to the test namespace:

``sample_buildout``
    This is the name of a buildout with a basic configuration.

``buildout``
    This is the path of the buildout script in the sample buildout.

``ls(*path)``
    List the contents of a directory.  The directory path is provided as one or
    more strings, to be joined with os.path.join.

``cat(*path)``
    Display the contents of a file.   The file path is provided as one or
    more strings, to be joined with os.path.join.

    On Windows, if the file doesn't exist, the function will try
    adding a '-script.py' suffix.  This helps to work around a
    difference in script generation on windows.

``mkdir(*path)``
    Create a directory. The directory path is provided as one or
    more strings, to be joined with os.path.join.

``rmdir(*path)``
    Remove a directory. The directory path is provided as one or
    more strings, to be joined with os.path.join.

``remove(*path)``
    Remove a directory or file. The path is provided as one or
    more strings, to be joined with os.path.join.

``tmpdir(name)``
    Create a temporary directory with the given name.  The directory
    will be automatically removed at the end of the test.  The path of
    the created directory is returned.

    Further, if the the normalize_path normlaizing substitution (see
    below) is used, then any paths starting with this path will be
    normalized to::

      /name/restofpath

    No two temporary directories can be created with the same name.  A
    directory created with tmpdir can be removed with rmdir and recreated.

    Note that the sample_buildout directory is created by calling this
    function.

``write(*path_and_contents)``
    Create a file.  The file path is provided as one or more strings,
    to be joined with os.path.join. The last argument is the file contents.

``system(command, input='')``
    Execute a system command with the given input passed to the
    command's standard input.  The output (error and regular output)
    from the command is returned.

``get(url)``
    Get a web page.

``cd(*path)``
    Change to the given directory.  The directory path is provided as one or
    more strings, to be joined with os.path.join.

    The directory will be reset at the end of the test.

``join(*path)``
    A convenient reference to os.path.join.

``register_teardown(func)``
    Register a tear-down function.  The function will be called with
    no arguments at the end of the test.

``start_server(path)``
    Start a web server on the given path.  The server will be shut
    down at the end of the test.  The server URL is returned.

    You can cause the server to start and stop logging it's output
    using: 

       &gt;&gt;&gt; get(server_url+'enable_server_logging')

    and:

       &gt;&gt;&gt; get(server_url+'disable_server_logging')

    This can be useful to see how buildout is interacting with a
    server.


``sdist(setup, dest)``
    Create a source distribution by running the given setup file and
    placing the result in the given destination directory.  If the
    setup argument is a directory, the thge setup.py file in that
    directory is used.

``bdist_egg(setup, executable, dest)``
    Create an egg by running the given setup file with the given
    Python executable and placing the result in the given destination
    directory.  If the setup argument is a directory, then the
    setup.py file in that directory is used.

``find_python(version)``
    Find a Python executable for the given version, where version is a
    string like "2.4".

    This function uses the following strategy to find a Python of the
    given version:

    - Look for an environment variable of the form PYTHON%(version)s.

    - On windows, look for \Pythonm%(version)s\python

    - on Unix, try running python%(version)s or just python to get the
      executable

``zc.buildout.testing.buildoutTearDown(test)``
----------------------------------------------

Tear down everything set up by zc.buildout.testing.buildoutSetUp.  Any
functions passed to register_teardown are called as well.

``install(project, destination)``
---------------------------------

Install eggs for a given project into a destination.  If the
destination is a test object, then the eggs directory of the
sample buildout (sample_buildout) defined by the test will be used.
Tests will use this to install the distributions for the packages
being tested (and their dependencies) into a sample buildout. The egg
to be used should already be loaded, by importing one of the modules
provided, before calling this function.

``install_develop(project, destination)``
-----------------------------------------

Like install, but a develop egg is installed even if the current egg
if not a develop egg.

``Output normalization``
------------------------

Recipe tests often generate output that is dependent on temporary file
locations, operating system conventions or Python versions.  To deal
with these dependencies, we often use
zope.testing.renormalizing.RENormalizing to normalize test output.
zope.testing.renormalizing.RENormalizing takes pairs of regular
expressions and substitutions. The zc.buildout.testing module provides
a few helpful variables that define regular-expression/substitution
pairs that you can pass to zope.testing.renormalizing.RENormalizing.


``normalize_path``
   Converts tests paths, based on directories created with tmpdir(),
   to simple paths.

``normalize_script``
   On Unix-like systems, scripts are implemented in single files
   without suffixes.  On windows, scripts are implemented with 2
   files, a -script.py file and a .exe file.  This normalization
   converts directory listings of Windows scripts to the form
   generated on UNix-like systems.

``normalize_egg_py``
   Normalize Python version and platform indicators, if specified, in
   egg names.

Python API for egg and script installation
==========================================

The easy_install module provides some functions to provide support for
egg and script installation.  It provides functionality at the python
level that is similar to easy_install, with a few exceptions:

- By default, we look for new packages *and* the packages that
  they depend on.  This is somewhat like (and uses) the --upgrade
  option of easy_install, except that we also upgrade required
  packages. 

- If the highest-revision package satisfying a specification is
  already present, then we don't try to get another one.  This saves a
  lot of search time in the common case that packages are pegged to
  specific versions.

- If there is a develop egg that satisfies a requirement, we don't
  look for additional distributions.  We always give preference to
  develop eggs.

- Distutils options for building extensions can be passed.

Distribution installation
-------------------------

The easy_install module provides a function, install, for installing one
or more packages and their dependencies.  The install function takes 2
positional arguments:

- An iterable of setuptools requirement strings for the distributions
  to be installed, and

- A destination directory to install to and to satisfy requirements
  from.  The destination directory can be None, in which case, no new
  distributions are downloaded and there will be an error if the
  needed distributions can't be found among those already installed.

It supports a number of optional keyword arguments:

links
   A sequence of URLs, file names, or directories to look for
   links to distributions.

index
   The URL of an index server, or almost any other valid URL. :)

   If not specified, the Python Package Index,
   http://cheeseshop.python.org/pypi, is used.  You can specify an
   alternate index with this option.  If you use the links option and
   if the links point to the needed distributions, then the index can
   be anything and will be largely ignored.  In the examples, here,
   we'll just point to an empty directory on our link server.  This 
   will make our examples run a little bit faster.

executable
   A path to a Python executable.  Distributions will be installed
   using this executable and will be for the matching Python version.

path
   A list of additional directories to search for locally-installed
   distributions.

always_unzip
   A flag indicating that newly-downloaded distributions should be
   directories even if they could be installed as zip files.

working_set
   An existing working set to be augmented with additional
   distributions, if necessary to satisfy requirements.  This allows
   you to call install multiple times, if necessary, to gather
   multiple sets of requirements.

newest
   A boolean value indicating whether to search for new distributions
   when already-installed distributions meet the requirement.  When
   this is true, the default, and when the destination directory is
   not None, then the install function will search for the newest
   distributions that satisfy the requirements.

versions
   A dictionary mapping project names to version numbers to be used
   when selecting distributions.  This can be used to specify a set of
   distribution versions independent of other requirements.

use_dependency_links
   A flag indicating whether to search for dependencies using the
   setup dependency_links metadata or not. If true, links are searched
   for using dependency_links in preference to other
   locations. Defaults to true.

The install method returns a working set containing the distributions
needed to meet the given requirements.

We have a link server that has a number of eggs:

    &gt;&gt;&gt; print get(link_server),
    &lt;html&gt;&lt;body&gt;
    &lt;a href="demo-0.1-py2.4.egg"&gt;demo-0.1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.2-py2.4.egg"&gt;demo-0.2-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.3-py2.4.egg"&gt;demo-0.3-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.4c1-py2.4.egg"&gt;demo-0.4c1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.0.zip"&gt;demoneeded-1.0.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.1.zip"&gt;demoneeded-1.1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.2c1.zip"&gt;demoneeded-1.2c1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="extdemo-1.4.zip"&gt;extdemo-1.4.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="index/"&gt;index/&lt;/a&gt;&lt;br&gt;
    &lt;a href="other-1.0-py2.4.egg"&gt;other-1.0-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;/body&gt;&lt;/html&gt;

Let's make a directory and install the demo egg to it, using the demo:

    &gt;&gt;&gt; dest = tmpdir('sample-install')
    &gt;&gt;&gt; import zc.buildout.easy_install
    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo==0.2'], dest,
    ...     links=[link_server], index=link_server+'index/')
    
We requested version 0.2 of the demo distribution to be installed into
the destination server.  We specified that we should search for links
on the link server and that we should use the (empty) link server 
index directory as a package index.

The working set contains the distributions we retrieved.

    &gt;&gt;&gt; for dist in ws:
    ...     print dist
    demo 0.2
    demoneeded 1.1

We got demoneeded because it was a dependency of demo.

And the actual eggs were added to the eggs directory.

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    -  demoneeded-1.1-py2.4.egg

If we remove the version restriction on demo, but specify a false
value for newest, no new distributions will be installed:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     newest=False)
    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    -  demoneeded-1.1-py2.4.egg

If we leave off the newest option, we'll get an update for demo:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/')
    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    -  demo-0.3-py2.4.egg
    -  demoneeded-1.1-py2.4.egg

Note that we didn't get the newest versions available.  There were
release candidates for newer versions of both packages. By default,
final releases are preferred.  We can change this behavior using the
prefer_final function:

    &gt;&gt;&gt; zc.buildout.easy_install.prefer_final(False)
    True

The old setting is returned.

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/')
    &gt;&gt;&gt; for dist in ws:
    ...     print dist
    demo 0.4c1
    demoneeded 1.2c1

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    -  demo-0.3-py2.4.egg
    -  demo-0.4c1-py2.4.egg
    -  demoneeded-1.1-py2.4.egg
    -  demoneeded-1.2c1-py2.4.egg

Let's put the setting back to the default.

    &gt;&gt;&gt; zc.buildout.easy_install.prefer_final(True)
    False

We can supply additional distributions.  We can also supply
specifications for distributions that would normally be found via
dependencies.  We might do this to specify a specific version.

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo', 'other', 'demoneeded==1.0'], dest,
    ...     links=[link_server], index=link_server+'index/')

    &gt;&gt;&gt; for dist in ws:
    ...     print dist
    demo 0.3
    other 1.0
    demoneeded 1.0

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    -  demo-0.3-py2.4.egg
    -  demo-0.4c1-py2.4.egg
    -  demoneeded-1.0-py2.4.egg
    -  demoneeded-1.1-py2.4.egg
    -  demoneeded-1.2c1-py2.4.egg
    d  other-1.0-py2.4.egg

We can request that eggs be unzipped even if they are zip safe.  This
can be useful when debugging.

    &gt;&gt;&gt; rmdir(dest)
    &gt;&gt;&gt; dest = tmpdir('sample-install')
    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     always_unzip=True)

    &gt;&gt;&gt; ls(dest)
    d  demo-0.3-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    
    &gt;&gt;&gt; rmdir(dest)
    &gt;&gt;&gt; dest = tmpdir('sample-install')
    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     always_unzip=True)

    &gt;&gt;&gt; ls(dest)
    d  demo-0.3-py2.4.egg
    d  demoneeded-1.1-py2.4.egg

Specifying version information independent of requirements
----------------------------------------------------------

Sometimes it's useful to specify version information independent of
normal requirements specifications.  For example, a buildout may need
to lock down a set of versions, without having to put put version
numbers in setup files or part definitions.  If a dictionary is passed
to the install function, mapping project names to version numbers,
then the versions numbers will be used.

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     versions = dict(demo='0.2', demoneeded='1.0'))
    &gt;&gt;&gt; [d.version for d in ws]
    ['0.2', '1.0']

In this example, we specified a version for demoneeded, even though we
didn't define a requirement for it.  The versions specified apply to
dependencies as well as the specified requirements.

If we specify a version that's incompatible with a requirement, then
we'll get an error:

    &gt;&gt;&gt; from zope.testing.loggingsupport import InstalledHandler
    &gt;&gt;&gt; handler = InstalledHandler('zc.buildout.easy_install')
    &gt;&gt;&gt; import logging
    &gt;&gt;&gt; logging.getLogger('zc.buildout.easy_install').propagate = False

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo &gt;0.2'], dest, links=[link_server],
    ...     index=link_server+'index/',
    ...     versions = dict(demo='0.2', demoneeded='1.0'))
    Traceback (most recent call last):
    ...
    IncompatibleVersionError: Bad version 0.2

    &gt;&gt;&gt; print handler
    zc.buildout.easy_install DEBUG
      Installing 'demo &gt;0.2'.
    zc.buildout.easy_install ERROR
      The version, 0.2, is not consistent with the requirement, 'demo&gt;0.2'.

    &gt;&gt;&gt; handler.clear()

If no versions are specified, a debugging message will be output 
reporting that a version was picked automatically:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     )

    &gt;&gt;&gt; print handler
    zc.buildout.easy_install DEBUG
      Installing 'demo'.
    zc.buildout.easy_install DEBUG
      We have the best distribution that satisfies 'demo'.
    zc.buildout.easy_install DEBUG
      Picked: demo = 0.3
    zc.buildout.easy_install DEBUG
      Getting required 'demoneeded'
    zc.buildout.easy_install DEBUG
        required by demo 0.3.
    zc.buildout.easy_install DEBUG
      We have the best distribution that satisfies 'demoneeded'.
    zc.buildout.easy_install DEBUG
      Picked: demoneeded = 1.1

    &gt;&gt;&gt; handler.uninstall()
    &gt;&gt;&gt; logging.getLogger('zc.buildout.easy_install').propagate = True

We can request that we get an error if versions are picked:

    &gt;&gt;&gt; zc.buildout.easy_install.allow_picked_versions(False)
    True

(The old setting is returned.)

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     )
    Traceback (most recent call last):
    ...
    UserError: Picked: demo = 0.3

    &gt;&gt;&gt; zc.buildout.easy_install.allow_picked_versions(True)
    False

The function default_versions can be used to get and set default
version information to be used when no version information is passes.
If called with an argument, it sets the default versions:

    &gt;&gt;&gt; zc.buildout.easy_install.default_versions(dict(demoneeded='1'))
    {}

It always returns the previous default versions.  If called without an
argument, it simply returns the default versions without changing
them:

    &gt;&gt;&gt; zc.buildout.easy_install.default_versions()
    {'demoneeded': '1'}

So with the default versions set, we'll get the requested version even
if the versions option isn't used:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     )

    &gt;&gt;&gt; [d.version for d in ws]
    ['0.3', '1.0']

Of course, we can unset the default versions by passing an empty
dictionary:

    &gt;&gt;&gt; zc.buildout.easy_install.default_versions({})
    {'demoneeded': '1'}

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest, links=[link_server], index=link_server+'index/',
    ...     )

    &gt;&gt;&gt; [d.version for d in ws]
    ['0.3', '1.1']

Dependency links
----------------

Setuptools allows metadata that describes where to search for package
dependencies. This option is called dependency_links. Buildout has its
own notion of where to look for dependencies, but it also uses the
setup tools dependency_links information if it's available.

Let's demo this by creating an egg that specifies dependency_links. 

To begin, let's create a new egg repository. This repository hold a
newer version of the 'demoneeded' egg than the sample repository does.

    &gt;&gt;&gt; repoloc = tmpdir('repo')
    &gt;&gt;&gt; from zc.buildout.tests import create_egg
    &gt;&gt;&gt; create_egg('demoneeded', '1.2', repoloc)
    &gt;&gt;&gt; link_server2 = start_server(repoloc)

Turn on logging on this server so that we can see when eggs are pulled
from it.
    
    &gt;&gt;&gt; get(link_server2 + 'enable_server_logging')
    GET 200 /enable_server_logging
    ''

Now we can create an egg that specifies that its dependencies are
found on this server.

    &gt;&gt;&gt; repoloc = tmpdir('repo2')
    &gt;&gt;&gt; create_egg('hasdeps', '1.0', repoloc, 
    ...            install_requires = "'demoneeded'",
    ...            dependency_links = [link_server2])

Let's add the egg to another repository.

    &gt;&gt;&gt; link_server3 = start_server(repoloc)

Now let's install the egg.

    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest,
    ...     links=[link_server3], index=link_server3+'index/')
    GET 200 /
    GET 200 /demoneeded-1.2-pyN.N.egg

The server logs show that the dependency was retrieved from the server
specified in the dependency_links.

Now let's see what happens if we provide two different ways to retrieve
the dependencies.

    &gt;&gt;&gt; rmdir(example_dest)
    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest, index=link_server+'index/',
    ...     links=[link_server, link_server3])
    GET 200 /
    GET 200 /demoneeded-1.2-pyN.N.egg

Once again the dependency is fetched from the logging server even
though it is also available from the non-logging server. This is
because the version on the logging server is newer and buildout
normally chooses the newest egg available.

If you wish to control where dependencies come from regardless of
dependency_links setup metadata use the 'use_dependency_links' option
to zc.buildout.easy_install.install().

    &gt;&gt;&gt; rmdir(example_dest)
    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest, index=link_server+'index/',
    ...     links=[link_server, link_server3],
    ...     use_dependency_links=False)

Notice that this time the dependency egg is not fetched from the
logging server. When you specify not to use dependency_links, eggs
will only be searched for using the links you explicitly provide.

Another way to control this option is with the
zc.buildout.easy_install.use_dependency_links() function. This
function sets the default behavior for the zc.buildout.easy_install()
function.

    &gt;&gt;&gt; zc.buildout.easy_install.use_dependency_links(False)
    True

The function returns its previous setting.

    &gt;&gt;&gt; rmdir(example_dest)
    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest, index=link_server+'index/',
    ...     links=[link_server, link_server3])

It can be overridden by passing a keyword argument to the install
function.

    &gt;&gt;&gt; rmdir(example_dest)
    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest, index=link_server+'index/',
    ...     links=[link_server, link_server3],
    ...	    use_dependency_links=True)
    GET 200 /demoneeded-1.2-pyN.N.egg

To return the dependency_links behavior to normal call the function again.

    &gt;&gt;&gt; zc.buildout.easy_install.use_dependency_links(True)
    False
    &gt;&gt;&gt; rmdir(example_dest)
    &gt;&gt;&gt; example_dest = tmpdir('example-install')
    &gt;&gt;&gt; workingset = zc.buildout.easy_install.install(
    ...     ['hasdeps'], example_dest, index=link_server+'index/',
    ...     links=[link_server, link_server3])
    GET 200 /demoneeded-1.2-pyN.N.egg


Script generation
-----------------

The easy_install module provides support for creating scripts from
eggs.  It provides a function similar to setuptools except that it
provides facilities for baking a script's path into the script.  This
has two advantages:

- The eggs to be used by a script are not chosen at run time, making
  startup faster and, more importantly, deterministic.

- The script doesn't have to import pkg_resources because the logic
  that pkg_resources would execute at run time is executed at
  script-creation time.

The scripts method can be used to generate scripts. Let's create a
destination directory for it to place them in:

    &gt;&gt;&gt; import tempfile
    &gt;&gt;&gt; bin = tmpdir('bin')

Now, we'll use the scripts method to generate scripts in this directory
from the demo egg:

    &gt;&gt;&gt; import sys
    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...     ['demo'], ws, sys.executable, bin)

the four arguments we passed were:

1. A sequence of distribution requirements.  These are of the same
   form as setuptools requirements.  Here we passed a single
   requirement, for the version 0.1 demo distribution.

2. A working set,

3. The Python executable to use, and 

3. The destination directory.

The bin directory now contains a generated script:

    &gt;&gt;&gt; ls(bin)
    -  demo

The return value is a list of the scripts generated:
    
    &gt;&gt;&gt; import os, sys
    &gt;&gt;&gt; if sys.platform == 'win32':
    ...     scripts == [os.path.join(bin, 'demo.exe'), 
    ...                 os.path.join(bin, 'demo-script.py')]
    ... else:
    ...     scripts == [os.path.join(bin, 'demo')]
    True

Note that in Windows, 2 files are generated for each script.  A script
file, ending in '-script.py', and an exe file that allows the script
to be invoked directly without having to specify the Python
interpreter and without having to provide a '.py' suffix.

The demo script run the entry point defined in the demo egg:

    &gt;&gt;&gt; cat(bin, 'demo') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    &lt;BLANKLINE&gt;
    import sys
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    import eggrecipedemo
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        eggrecipedemo.main()

Some things to note:

- The demo and demoneeded eggs are added to the beginning of sys.path.

- The module for the script entry point is imported and the entry
  point, in this case, 'main', is run.

Rather than requirement strings, you can pass tuples containing 3
strings:

  - A script name,

  - A module,

  - An attribute expression for an entry point within the module.

For example, we could have passed entry point information directly
rather than passing a requirement:

    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...     [('demo', 'eggrecipedemo', 'main')],
    ...     ws, sys.executable, bin)

    &gt;&gt;&gt; cat(bin, 'demo') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    &lt;BLANKLINE&gt;
    import sys
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    import eggrecipedemo
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        eggrecipedemo.main()

Passing entry-point information directly is handy when using eggs (or
distributions) that don't declare their entry points, such as
distributions that aren't based on setuptools.

The interpreter keyword argument can be used to generate a script that can
be used to invoke the Python interactive interpreter with the path set
based on the working set.  This generated script can also be used to
run other scripts with the path set on the working set:

    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...     ['demo'], ws, sys.executable, bin, interpreter='py')


    &gt;&gt;&gt; ls(bin)
    -  demo
    -  py

    &gt;&gt;&gt; if sys.platform == 'win32':
    ...     scripts == [os.path.join(bin, 'demo.exe'),
    ...                 os.path.join(bin, 'demo-script.py'),
    ...                 os.path.join(bin, 'py.exe'),
    ...                 os.path.join(bin, 'py-script.py')]
    ... else:
    ...     scripts == [os.path.join(bin, 'demo'),
    ...                 os.path.join(bin, 'py')]
    True

The py script simply runs the Python interactive interpreter with
the path set:

    &gt;&gt;&gt; cat(bin, 'py') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    import sys
    &lt;BLANKLINE&gt;
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    _interactive = True
    if len(sys.argv) &gt; 1:
        import getopt
        _options, _args = getopt.getopt(sys.argv[1:], 'ic:')
        _interactive = False
        for (_opt, _val) in _options:
            if _opt == '-i':
                _interactive = True
            elif _opt == '-c':
                exec _val
    &lt;BLANKLINE&gt;
        if _args:
            sys.argv[:] = _args
            execfile(sys.argv[0])
    &lt;BLANKLINE&gt;
    if _interactive:
        import code
        code.interact(banner="", local=globals())

If invoked with a script name and arguments, it will run that script, instead.

An additional argument can be passed to define which scripts to install
and to provide script names. The argument is a dictionary mapping
original script names to new script names.

    &gt;&gt;&gt; bin = tmpdir('bin2')
    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...    ['demo'], ws, sys.executable, bin, dict(demo='run'))

    &gt;&gt;&gt; if sys.platform == 'win32':
    ...     scripts == [os.path.join(bin, 'run.exe'),
    ...                 os.path.join(bin, 'run-script.py')]
    ... else:
    ...     scripts == [os.path.join(bin, 'run')]
    True
    &gt;&gt;&gt; ls(bin)
    -  run

    &gt;&gt;&gt; print system(os.path.join(bin, 'run')),
    3 1

Including extra paths in scripts
--------------------------------

We can pass a keyword argument, extra paths, to cause additional paths
to be included in the a generated script:

    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...    ['demo'], ws, sys.executable, bin, dict(demo='run'),
    ...    extra_paths=['/foo/bar'])

    &gt;&gt;&gt; cat(bin, 'run') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    &lt;BLANKLINE&gt;
    import sys
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      '/foo/bar',
      ]
    &lt;BLANKLINE&gt;
    import eggrecipedemo
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        eggrecipedemo.main()

Providing script arguments
--------------------------

An "argument" keyword argument can be used to pass arguments to an
entry point.  The value passed is a source string to be placed between the
parentheses in the call:

    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...    ['demo'], ws, sys.executable, bin, dict(demo='run'),
    ...    arguments='1, 2')

    &gt;&gt;&gt; cat(bin, 'run') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    import sys
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    import eggrecipedemo
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        eggrecipedemo.main(1, 2)

Passing initialization code
---------------------------

You can also pass script initialization code:

    &gt;&gt;&gt; scripts = zc.buildout.easy_install.scripts(
    ...    ['demo'], ws, sys.executable, bin, dict(demo='run'),
    ...    arguments='1, 2', 
    ...    initialization='import os\nos.chdir("foo")')

    &gt;&gt;&gt; cat(bin, 'run') # doctest: +NORMALIZE_WHITESPACE
    #!/usr/local/bin/python2.4
    import sys
    sys.path[0:0] = [
      '/sample-install/demo-0.3-py2.4.egg',
      '/sample-install/demoneeded-1.1-py2.4.egg',
      ]
    &lt;BLANKLINE&gt;
    import os
    os.chdir("foo")
    &lt;BLANKLINE&gt;
    import eggrecipedemo
    &lt;BLANKLINE&gt;
    if __name__ == '__main__':
        eggrecipedemo.main(1, 2)


Handling custom build options for extensions provided in source distributions
-----------------------------------------------------------------------------

Sometimes, we need to control how extension modules are built.  The
build function provides this level of control.  It takes a single
package specification, downloads a source distribution, and builds it
with specified custom build options.

The build function takes 3 positional arguments:

spec
   A package specification for a source distribution

dest
   A destination directory

build_ext
   A dictionary of options to be passed to the distutils build_ext
   command when building extensions.

It supports a number of optional keyword arguments:

links
   a sequence of URLs, file names, or directories to look for
   links to distributions,

index
   The URL of an index server, or almost any other valid URL. :)

   If not specified, the Python Package Index,
   http://cheeseshop.python.org/pypi, is used.  You can specify an
   alternate index with this option.  If you use the links option and
   if the links point to the needed distributions, then the index can
   be anything and will be largely ignored.  In the examples, here,
   we'll just point to an empty directory on our link server.  This 
   will make our examples run a little bit faster.

executable
   A path to a Python executable.  Distributions will be installed
   using this executable and will be for the matching Python version.

path
   A list of additional directories to search for locally-installed
   distributions.

newest
   A boolean value indicating whether to search for new distributions
   when already-installed distributions meet the requirement.  When
   this is true, the default, and when the destination directory is
   not None, then the install function will search for the newest
   distributions that satisfy the requirements.

versions
   A dictionary mapping project names to version numbers to be used
   when selecting distributions.  This can be used to specify a set of
   distribution versions independent of other requirements.


Our link server included a source distribution that includes a simple
extension, extdemo.c::

  #include &lt;Python.h&gt;
  #include &lt;extdemo.h&gt;

  static PyMethodDef methods[] = {};

  PyMODINIT_FUNC
  initextdemo(void)
  {
      PyObject *m;
      m = Py_InitModule3("extdemo", methods, "");
  #ifdef TWO
      PyModule_AddObject(m, "val", PyInt_FromLong(2));
  #else
      PyModule_AddObject(m, "val", PyInt_FromLong(EXTDEMO));
  #endif
  }

The extension depends on a system-dependent include file, extdemo.h,
that defines a constant, EXTDEMO, that is exposed by the extension.

We'll add an include directory to our sample buildout and add the
needed include file to it:

    &gt;&gt;&gt; mkdir('include')
    &gt;&gt;&gt; write('include', 'extdemo.h',
    ... """
    ... #define EXTDEMO 42
    ... """)

Now, we can use the build function to create an egg from the source
distribution:

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/')
    ['/sample-install/extdemo-1.4-py2.4-unix-i686.egg']

The function returns the list of eggs 

Now if we look in our destination directory, we see we have an extdemo egg:

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    d  demo-0.3-py2.4.egg
    -  demoneeded-1.0-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    d  extdemo-1.4-py2.4-unix-i686.egg

Let's update our link server with a new version of extdemo:

    &gt;&gt;&gt; update_extdemo()
    &gt;&gt;&gt; print get(link_server),
    &lt;html&gt;&lt;body&gt;
    &lt;a href="demo-0.1-py2.4.egg"&gt;demo-0.1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.2-py2.4.egg"&gt;demo-0.2-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.3-py2.4.egg"&gt;demo-0.3-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demo-0.4c1-py2.4.egg"&gt;demo-0.4c1-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.0.zip"&gt;demoneeded-1.0.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.1.zip"&gt;demoneeded-1.1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="demoneeded-1.2c1.zip"&gt;demoneeded-1.2c1.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="extdemo-1.4.zip"&gt;extdemo-1.4.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="extdemo-1.5.zip"&gt;extdemo-1.5.zip&lt;/a&gt;&lt;br&gt;
    &lt;a href="index/"&gt;index/&lt;/a&gt;&lt;br&gt;
    &lt;a href="other-1.0-py2.4.egg"&gt;other-1.0-py2.4.egg&lt;/a&gt;&lt;br&gt;
    &lt;/body&gt;&lt;/html&gt;

The easy_install caches information about servers to reduce network
access. To see the update, we have to call the clear_index_cache
function to clear the index cache:

    &gt;&gt;&gt; zc.buildout.easy_install.clear_index_cache()

If we run build with newest set to False, we won't get an update:

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/',
    ...   newest=False)
    ['/sample-install/extdemo-1.4-py2.4-linux-i686.egg']

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    d  demo-0.3-py2.4.egg
    -  demoneeded-1.0-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    d  extdemo-1.4-py2.4-unix-i686.egg

But if we run it with the default True setting for newest, then we'll
get an updated egg:

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/')
    ['/sample-install/extdemo-1.5-py2.4-unix-i686.egg']

    &gt;&gt;&gt; ls(dest)
    -  demo-0.2-py2.4.egg
    d  demo-0.3-py2.4.egg
    -  demoneeded-1.0-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    d  extdemo-1.4-py2.4-unix-i686.egg
    d  extdemo-1.5-py2.4-unix-i686.egg

The versions option also influences the versions used.  For example,
if we specify a version for extdemo, then that will be used, even
though it isn't the newest.  Let's clean out the destination directory
first:

    &gt;&gt;&gt; import os
    &gt;&gt;&gt; for name in os.listdir(dest):
    ...     remove(dest, name)

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/',
    ...   versions=dict(extdemo='1.4'))
    ['/sample-install/extdemo-1.4-py2.4-unix-i686.egg']

    &gt;&gt;&gt; ls(dest)
    d  extdemo-1.4-py2.4-unix-i686.egg

Handling custom build options for extensions in develop eggs
------------------------------------------------------------

The develop function is similar to the build function, except that,
rather than building an egg from a source directory containing a
setup.py script.  

The develop function takes 2 positional arguments:

setup
   The path to a setup script, typically named "setup.py", or a
   directory containing a setup.py script.

dest
   The directory to install the egg link to

It supports some optional keyword argument:

build_ext
   A dictionary of options to be passed to the distutils build_ext
   command when building extensions.

executable
   A path to a Python executable.  Distributions will be installed
   using this executable and will be for the matching Python version.

We have a local directory containing the extdemo source:

    &gt;&gt;&gt; ls(extdemo)
    -  MANIFEST
    -  MANIFEST.in
    -  README
    -  extdemo.c
    -  setup.py

Now, we can use the develop function to create a develop egg from the source
distribution:

    &gt;&gt;&gt; zc.buildout.easy_install.develop(
    ...   extdemo, dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')})
    '/sample-install/extdemo.egg-link'

The name of the egg link created is returned.

Now if we look in our destination directory, we see we have an extdemo
egg link:

    &gt;&gt;&gt; ls(dest)
    d  extdemo-1.4-py2.4-unix-i686.egg
    -  extdemo.egg-link

And that the source directory contains the compiled extension:

    &gt;&gt;&gt; ls(extdemo)
    -  MANIFEST
    -  MANIFEST.in
    -  README
    d  build
    -  extdemo.c
    d  extdemo.egg-info
    -  extdemo.so
    -  setup.py

Download cache
--------------

Normally, when distributions are installed, if any processing is
needed, they are downloaded from the internet to a temporary directory
and then installed from there.  A download cache can be used to avoid
the download step.  This can be useful to reduce network access and to
create source distributions of an entire buildout.

A download cache is specified by calling the download_cache
function.  The function always returns the previous setting. If no
argument is passed, then the setting is unchanged.  If an argument is
passed, the download cache is set to the given path, which must point
to an existing directory.  Passing None clears the cache setting.

To see this work, we'll create a directory and set it as the cache
directory:

    &gt;&gt;&gt; cache = tmpdir('cache')
    &gt;&gt;&gt; zc.buildout.easy_install.download_cache(cache)

We'll recreate our destination directory:

    &gt;&gt;&gt; remove(dest)
    &gt;&gt;&gt; dest = tmpdir('sample-install')

We'd like to see what is being fetched from the server, so we'll
enable server logging:
   
    &gt;&gt;&gt; get(link_server+'enable_server_logging')
    GET 200 /enable_server_logging
    ''

Now, if we install demo, and extdemo:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo==0.2'], dest,
    ...     links=[link_server], index=link_server+'index/', 
    ...     always_unzip=True)
    GET 200 /
    GET 404 /index/demo/
    GET 200 /index/
    GET 200 /demo-0.2-py2.4.egg
    GET 404 /index/demoneeded/
    GET 200 /demoneeded-1.1.zip
    GET 404 /index/setuptools/

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/')
    GET 404 /index/extdemo/
    GET 200 /extdemo-1.5.zip
    ['/sample-install/extdemo-1.5-py2.4-linux-i686.egg']

Not only will we get eggs in our destination directory:

    &gt;&gt;&gt; ls(dest)
    d  demo-0.2-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    d  extdemo-1.5-py2.4-linux-i686.egg

But we'll get distributions in the cache directory:

    &gt;&gt;&gt; ls(cache)
    -  demo-0.2-py2.4.egg
    -  demoneeded-1.1.zip
    -  extdemo-1.5.zip

The cache directory contains uninstalled distributions, such as zipped
eggs or source distributions.  

Let's recreate our destination directory and clear the index cache:

    &gt;&gt;&gt; remove(dest)
    &gt;&gt;&gt; dest = tmpdir('sample-install')
    &gt;&gt;&gt; zc.buildout.easy_install.clear_index_cache()

Now when we install the distributions:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo==0.2'], dest,
    ...     links=[link_server], index=link_server+'index/', 
    ...     always_unzip=True)
    GET 200 /
    GET 404 /index/demo/
    GET 200 /index/
    GET 404 /index/demoneeded/
    GET 404 /index/setuptools/

    &gt;&gt;&gt; zc.buildout.easy_install.build(
    ...   'extdemo', dest, 
    ...   {'include-dirs': os.path.join(sample_buildout, 'include')},
    ...   links=[link_server], index=link_server+'index/')
    GET 404 /index/extdemo/
    ['/sample-install/extdemo-1.5-py2.4-linux-i686.egg']

    &gt;&gt;&gt; ls(dest)
    d  demo-0.2-py2.4.egg
    d  demoneeded-1.1-py2.4.egg
    d  extdemo-1.5-py2.4-linux-i686.egg

Note that we didn't download the distributions from the link server.

If we remove the restriction on demo, we'll download a newer version
from the link server:

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest,
    ...     links=[link_server], index=link_server+'index/', 
    ...     always_unzip=True)
    GET 200 /demo-0.3-py2.4.egg

Normally, the download cache is the preferred source of downloads, but
not the only one.

Installing solely from a download cache
---------------------------------------

A download cache can be used as the basis of application source
releases.  In an application source release, we want to distribute an
application that can be built without making any network accesses.  In
this case, we distribute a download cache and tell the easy_install
module to install from the download cache only, without making network
accesses.  The install_from_cache function can be used to signal that
packages should be installed only from the download cache.  The
function always returns the previous setting.  Calling it with no
arguments returns the current setting without changing it:

    &gt;&gt;&gt; zc.buildout.easy_install.install_from_cache()
    False

Calling it with a boolean value changes the setting and returns the
previous setting:

    &gt;&gt;&gt; zc.buildout.easy_install.install_from_cache(True)
    False

Let's remove demo-0.3-py2.4.egg from the cache, clear the index cache,
recreate the destination directory, and reinstall demo:

    &gt;&gt;&gt; for  f in os.listdir(cache):
    ...     if f.startswith('demo-0.3-'):
    ...         remove(cache, f)

    &gt;&gt;&gt; zc.buildout.easy_install.clear_index_cache()
    &gt;&gt;&gt; remove(dest)
    &gt;&gt;&gt; dest = tmpdir('sample-install')

    &gt;&gt;&gt; ws = zc.buildout.easy_install.install(
    ...     ['demo'], dest,
    ...     links=[link_server], index=link_server+'index/', 
    ...     always_unzip=True)

    &gt;&gt;&gt; ls(dest)
    d  demo-0.2-py2.4.egg
    d  demoneeded-1.1-py2.4.egg

This time, we didn't download from or even query the link server.

.. Disable the download cache:

    &gt;&gt;&gt; zc.buildout.easy_install.download_cache(None)
    '/cache'

    &gt;&gt;&gt; zc.buildout.easy_install.install_from_cache(False)
    True

Status
******

Change History
**************

1.0.1 (2008-04-02)
==================

- Made easy_install.py's _get_version except non final releases of Python,
  like 2.4.4c0. (hannosch)

- various patches for Windows (patch by Gottfried Ganssauge) (ajung)

- applied patch fixing rmtree issues on Windows (patch by
  Gottfried Ganssauge) (ajung)

1.0.0 (2008-01-13)
==================

- Added a french translation of the buildout tutorial

1.0.0b31 (2007-11-01)
=====================

Feature Changes
---------------

- Added a configuration option that allows buildouts to ignore
  dependency_links metadata specified in setup. By default
  dependency_links in setup are used in addition to buildout specified
  find-links. This can make it hard to control where eggs come
  from. Here's how to tell buildout to ignore URLs in
  dependency_links::

    [buildout]
    use-dependency-links = false

  By default use-dependency-links is true, which matches the behavior
  of previous versions of buildout.

- Added a configuration option that causes buildout to error if a
  version is picked. This is a nice safety belt when fixing all
  versions is intended, especially when creating releases.

Bugs Fixed
----------

- 151820: Develop failed if the setup.py script imported modules in
  the distribution directory.

- Verbose logging of the develop command was omitting detailed
  output.

- The setup command wasn't documented.

- The setup command failed if run in a directory without specifying a
  configuration file.

- The setup command raised a stupid exception if run without arguments.

- When using a local find links or index, distributions weren't copied
  to the download cache.

- When installing from source releases, a version specification (via a
  buildout versions section) for setuptools was ignored when deciding
  which setuptools to use to build an egg from the source release.

1.0.0b30 (2007-08-20)
=====================

Feature Changes
---------------

- Changed the default policy back to what it was to avoid breakage in
  existing buildouts.  Use::

    [buildout]
    prefer-final = true

  to get the new policy.  The new policy will go into effect in
  buildout 2.

1.0.0b29 (2007-08-20)
=====================

Feature Changes
---------------

- Now, final distributions are prefered over non-final versions.  If
  both final and non-final versions satisfy a requirement, then the
  final version will be used even if it is older.  The normal way to
  override this for specific packages is to specifically require a
  non-final version, either specifically or via a lower bound.

- There is a buildout prefer-final version that can be used with a
  value of "false"::

    prefer-final = false

  To prefer newer versions, regardless of whether or not they are
  final, buildout-wide.

- The new simple Python index, http://cheeseshop.python.org/simple, is
  used as the default index.  This will provide better performance
  than the human package index interface,
  http://pypi.python.org/pypi. More importantly, it lists hidden
  distributions, so buildouts with fixed distribution versions will be
  able to find old distributions even if the distributions have been
  hidden in the human PyPI interface.

Bugs Fixed
----------

- 126441: Look for default.cfg in the right place on Windows.

1.0.0b28 (2007-07-05)
=====================

Bugs Fixed
----------

- When requiring a specific version, buildout looked for new versions
  even if that single version was already installed.

1.0.0b27 (2007-06-20)
=====================

Bugs Fixed
----------

- Scripts were generated incorrectly on Windows.  This included the
  buildout script itself, making buildout completely unusable.

1.0.0b26 (2007-06-19)
=====================

Feature Changes
---------------

- Thanks to recent fixes in setuptools, I was able to change buildout
  to use find-link and index information when searching extensions.

  Sadly, this work, especially the timing, was motivated my the need
  to use alternate indexes due to performance problems in the cheese
  shop (http://www.python.org/pypi/).  I really home we can address
  these performance problems soon.

1.0.0b25 (2007-05-31)
=====================

Feature Changes
---------------

- buildout now changes to the buildout directory before running recipe
  install and update methods.

- Added a new init command for creating a new buildout. This creates
  an empty configuration file and then bootstraps.

- Except when using the new init command, it is now an error to run
  buildout without a configuration file.

- In verbose mode, when adding distributions to fulful requirements of
  already-added distributions, we now show why the new distributions
  are being added.

- Changed the logging format to exclude the logger name for the
  zc.buildout logger.  This reduces noise in the output.  

- Clean up lots of messages, adding missing periods and adding quotes around
  requirement strings and file paths.

Bugs Fixed
----------

- 114614: Buildouts could take a very long time if there were
  dependency problems in large sets of pathologically interdependent
  packages. 

- 59270: Buggy recipes can cause failures in later recipes via chdir

- 61890: file:// urls don't seem to work in find-links

  setuptools requires that file urls that point to directories must
  end in a "/".  Added a workaround.

- 75607: buildout should not run if it creates an empty buildout.cfg

1.0.0b24 (2007-05-09)
=====================

Feature Changes
---------------

- Improved error reporting by showing which packages require other
  packages that can't be found or that cause version conflicts.

- Added an API for use by recipe writers to clean up created files
  when recipe errors occur.

- Log installed scripts.

Bugs Fixed
----------

- 92891: bootstrap crashes with recipe option in buildout section.

- 113085: Buildout exited with a zero exist status when internal errors
  occured.


1.0.0b23 (2007-03-19)
=====================

Feature Changes
---------------

- Added support for download caches.  A buildout can specify a cache
  for distribution downloads.  The cache can be shared among buildouts
  to reduce network access and to support creating source
  distributions for applications allowing install without network
  access. 

- Log scripts created, as suggested in:
  https://bugs.launchpad.net/zc.buildout/+bug/71353

Bugs Fixed
----------

- It wasn't possible to give options on the command line for sections
  not defined in a configuration file.

1.0.0b22 (2007-03-15)
=====================

Feature Changes
---------------

- Improved error reporting and debugging support:

  - Added "logical tracebacks" that show functionally what the buildout
    was doing when an error occurs.  Don't show a Python traceback
    unless the -D option is used.

  - Added a -D option that causes the buildout to print a traceback and
    start the pdb post-mortem debugger when an error occurs.

  - Warnings are printed for unused options in the buildout section and
    installed-part sections.  This should make it easier to catch option
    misspellings.

- Changed the way the installed database (.installed.cfg) is handled
  to avoid database corruption when a user breaks out of a buildout
  with control-c.

- Don't save an installed database if there are no installed parts or
  develop egg links.

1.0.0b21 (2007-03-06)
=====================

Feature Changes
---------------

- Added support for repeatable buildouts by allowing egg versions to
  be specified in a versions section.

- The easy_install module install and build functions now accept a
  versions argument that supplied to mapping from project name to
  version numbers.  This can be used to fix version numbers for
  required distributions and their depenencies.

  When a version isn't fixed, using either a versions option or using
  a fixed version number in a requirement, then a debug log message is
  emitted indicating the version picked.  This is useful for setting
  versions options.

  A default_versions function can be used to set a default value for
  this option.

- Adjusted the output for verbosity levels.  Using a single -v option
  no longer causes voluminous setuptools output.  Uisng -vv and -vvv
  now triggers extra setuptools output.

- Added a remove testing helper function that removes files or directories.

1.0.0b20 (2007-02-08)
=====================

Feature Changes
---------------

- Added a buildout newest option, to control whether the newest
  distributions should be sought to meet requirements.  This might
  also provide a hint to recipes that don't deal with
  distributions. For example, a recipe that manages subversion
  checkouts might not update a checkout if newest is set to "false".

- Added a *newest* keyword parameter to the
  zc.buildout.easy_install.install and zc.buildout.easy_install.build
  functions to control whether the newest distributions that meed
  given requirements should be sought.  If a false value is provided
  for this parameter and already installed eggs meet the given
  requirements, then no attempt will be made to search for newer
  distributions.
 
- The recipe-testing support setUp function now adds the name
  *buildout* to the test namespace with a value that is the path to
  the buildout script in the sample buildout.  This allows tests to
  use

    &gt;&gt;&gt; print system(buildout),

  rather than:

    &gt;&gt;&gt; print system(join('bin', 'buildout')),


Bugs Fixed
----------

- Paths returned from update methods replaced lists of installed files
  rather than augmenting them.

1.0.0b19 (2007-01-24)
=====================

Bugs Fixed
----------

- Explicitly specifying a Python executable failed if the output of
  running Python with the -V option included a 2-digit (rather than a
  3-digit) version number.

1.0.0b18 (2007-01-22)
=====================

Feature Changes
---------------

- Added documentation for some previously undocumented features of the 
  easy_install APIs.

- By popular demand, added a -o command-line option that is a short
  hand for the assignment buildout:offline=true.

Bugs Fixed
----------

- When deciding whether recipe develop eggs had changed, buildout
  incorrectly considered files in .svn and CVS directories.

1.0.0b17 (2006-12-07)
=====================

Feature Changes
---------------

- Configuration files can now be loaded from URLs.

Bugs Fixed
----------

- https://bugs.launchpad.net/products/zc.buildout/+bug/71246

  Buildout extensions installed as eggs couldn't be loaded in offline
  mode.


1.0.0b16 (2006-12-07)
=====================

Feature Changes
---------------

- A new command-line argument, -U, suppresses reading user defaults.

- You can now suppress use of an installed-part database
  (e.g. .installed.cfg) by sprifying an empty value for the buildout
  installed option.

Bugs Fixed
----------

- When the install command is used with a list of parts, only
  those parts are supposed to be installed, but the buildout was also
  building parts that those parts depended on.

1.0.0b15 (2006-12-06)
=====================

Bugs Fixed
----------

- Uninstall recipes weren't loaded correctly in cases where
  no parts in the (new) configuration used the recipe egg.

1.0.0b14 (2006-12-05)
=====================

Feature Changes
---------------

- Added uninstall recipes for dealing with complex uninstallation
  scenarios.

Bugs Fixed
----------

- Automatic upgrades weren't performed on Windows due to a bug that
  caused buildout to incorrectly determine that it wasn't running
  locally in a buildout.

- Fixed some spurious test failures on Windows.

1.0.0b13 (2006-12-04)
=====================

Feature Changes
---------------

- Variable substitutions now reflect option data written by recipes.

- A part referenced by a part in a parts list is now added to the parts
  list before the referencing part.  This means that you can omit
  parts from the parts list if they are referenced by other parts.

- Added a develop function to the easy_install module to aid in
  creating develop eggs with custom build_ext options.

- The build and develop functions in the easy_install module now
  return the path of the egg or egg link created.

- Removed the limitation that parts named in the install command can
  only name configured parts.

- Removed support ConfigParser-style variable substitutions
  (e.g. %(foo)s). Only the string-template style of variable
  (e.g. ${section:option}) substitutions will be supported.
  Supporting both violates "there's only one way to do it".

- Deprecated the buildout-section extendedBy option.

Bugs Fixed
----------

- We treat setuptools as a dependency of any distribution that
  (declares that it) uses namespace packages, whether it declares
  setuptools as a dependency or not.  This wasn't working for eggs
  intalled by virtue of being dependencies.


1.0.0b12 (2006-10-24)
=====================

Feature Changes
---------------

- Added an initialization argument to the
  zc.buildout.easy_install.scripts function to include initialization
  code in generated scripts.

1.0.0b11 (2006-10-24)
=====================

Bugs Fixed
----------

`67737 &lt;https://launchpad.net/products/zc.buildout/+bug/67737&gt;`_
     Verbose and quite output options caused errors when the 
     develop buildout option was used to create develop eggs.

`67871 &lt;https://launchpad.net/products/zc.buildout/+bug/67871&gt;`_
     Installation failed if the source was a (local) unzipped
     egg.

`67873 &lt;https://launchpad.net/products/zc.buildout/+bug/67873&gt;`_
     There was an error in producing an error message when part names
     passed to the install command weren't included in the
     configuration. 

1.0.0b10 (2006-10-16)
=====================

Feature Changes
---------------

- Renamed the runsetup command to setup. (The old name still works.)

- Added a recipe update method. Now install is only called when a part
  is installed for the first time, or after an uninstall. Otherwise, 
  update is called.  For backward compatibility, recipes that don't
  define update methiods are still supported.

- If a distribution defines namespace packages but fails to declare 
  setuptools as one of its dependencies, we now treat setuptools as an 
  implicit dependency.  We generate a warning if the distribution
  is a develop egg.

- You can now create develop eggs for setup scripts that don't use setuptools.

Bugs Fixed
----------

- Egg links weren't removed when corresponding entries were removed
  from develop sections.

- Running a non-local buildout command (one not installed in the
  buildout) ket to a hang if there were new versions of zc.buildout or
  setuptools were available.  Now we issue a warning and don't
  upgrade.

- When installing zip-safe eggs from local directories, the eggs were
  moved, rather than copied, removing them from the source directory.

1.0.0b9 (2006-10-02)
====================

Bugs Fixed
----------

Non-zip-safe eggs were not unzipped when they were installed.

1.0.0b8 (2006-10-01)
====================

Bugs Fixed
----------

- Installing source distributions failed when using alternate Python
  versions (depending on the versions of Python used.)

- Installing eggs wasn't handled as efficiently as possible due to a
  bug in egg URL parsing.

- Fixed a bug in runsetup that caused setup scripts that introspected
  __file__ to fail.

1.0.0b7
=======

Added a documented testing framework for use by recipes. Refactored
the buildout tests to use it.

Added a runsetup command run a setup script.  This is handy if, like
me, you don't install setuptools in your system Python.

1.0.0b6
=======

Fixed https://launchpad.net/products/zc.buildout/+bug/60582
Use of extension options caused bootstrapping to fail if the eggs
directory didn't already exist.  We no longer use extensions for
bootstrapping.  There really isn't any reason to anyway.


1.0.0b5
=======

Refactored to do more work in buildout and less work in easy_install.
This makes things go a little faster, makes errors a little easier to
handle, and allows extensions (like the sftp extension) to influence
more of the process. This was done to fix a problem in using the sftp
support.

1.0.0b4
=======

- Added an **experimental** extensions mechanism, mainly to support
  adding sftp support to buildouts that need it.

- Fixed buildout self-updating on Windows.

1.0.0b3
=======

- Added a help option (-h, --help)

- Increased the default level of verbosity.

- Buildouts now automatically update themselves to new versions of
  zc.buildout and setuptools.

- Added Windows support.

- Added a recipe API for generating user errors.

- No-longer generate a py_zc.buildout script.

- Fixed some bugs in variable substitutions.  

  The characters "-", "." and " ", weren't allowed in section or
  option names.

  Substitutions with invalid names were ignored, which caused
  missleading failures downstream.

- Improved error handling.  No longer show tracebacks for user errors.

- Now require a recipe option (and therefore a section) for every part.

- Expanded the easy_install module API to:

  - Allow extra paths to be provided

  - Specify explicit entry points

  - Specify entry-point arguments

1.0.0b2
=======

Added support for specifying some build_ext options when installing eggs
from source distributions.

1.0.0b1
=======

- Changed the bootstrapping code to only install setuptools and
  zc.buildout. The bootstrap code no-longer runs the buildout itself.
  This was to fix a bug that caused parts to be recreated
  unnecessarily because the recipe signature in the initial buildout
  reflected temporary locations for setuptools and zc.buildout.

- Now create a minimal setup.py if it doesn't exist and issue a
  warning that it is being created.

- Fixed bug in saving installed configuration data.  %'s and extra
  spaces weren't quoted.

1.0.0a1
=======

Initial public version

Download
**********************</description>
<homepage rdf:resource="http://www.python.org/pypi/zc.buildout" />
<maintainer><foaf:Person><foaf:name>Jim Fulton</foaf:name>
<foaf:mbox_sha1sum>0491e393764bbbfa13324a845db4ee27f7641b78</foaf:mbox_sha1sum></foaf:Person></maintainer>
<release><Version><revision>1.0.1</revision></Version></release>
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