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docker-forklift 0.2

Utility for running a container

Latest Version: 0.2.51

Forklift - when you need to handle just one container

Utilities to develop a containerised application.

The standard containers at InfoXchange require a number of environment
variables to run properly. With Forklift, they can be inferred automatically
and/or specified in the codebase.

Furthermore, it is often necessary to experiment within a running container.
Forklift includes a special 'sshd' mode to start the SSH daemon instead of the
original command, so that one can run arbitary commands inside.


sudo pip install .

Or in a virtualenv:

pip install .

Warning: Forklift requires Python 3, and you should use the corresponding `pip`
to install, for example, `pip-3.2` on Debian and `pip3` on Ubuntu
(`sudo apt-get install python3-pip`). If unsure, check that `pip --version`
reports being `python 3`.

Running Forklift

The basic invocation is:


What happens is:

* The configuration files are being searched for a list of services to provide
to the command.
* For all of those services, an available provider is searched for.
* The found services, along with any additional configured environment, are
passed to the command as environment variables.

For example, if the project specifies:

- postgresql

Forklift will check if the PostgreSQL server is running on the local machine,
and pass the database URL to the application.


Forklift can run commands directly or Docker containers. By default, if the
application given is an existing file (e.g. `./`), it is run directly.
Otherwise it is assumed to be a Docker image to create a container from.
The environment is passed to the application in either case.

To override the choice, set `driver` parameter to either `docker` or `direct`.

Docker driver has specific parameters:

* `rm`: Automatically remove containers after they've stopped.
* `privileged`: Run containers in privileged mode.
* `interactive`: Run containers in interactive mode (`-i -t`).
* `storage`: Run the container with `/storage` mounted as a volume under the
specified path.
* `mount-root`: Bind mount the root directory of the container filesystem to
the specified path.

### SSH daemon mode

Forklift can set up an SSH server inside the container, passing in all the
environment and adding the user public key. To use this mode, pass `sshd` as
the command (e.g. `forklift ubuntu sshd`).

The following additional options apply in SSH daemon mode:

* `user` - the user to set up for SSH in the container, defaults to `app`.
* `identity` - the public key file to authorise logging in as. Can be specified
as the full path or as a file in `~/.ssh`.
* `host-uid` - for ease to use with `mount-root`, the UID of the user inside
the container is changed to the one of the host user; override if needed.

When running in SSH daemon mode, Forklift starts the container in the
background and prints a command to SSH to it. It is up to the user to stop
the container when no longer needed.

Services and environment

The following environment is always available to the running application:

* `ENVIRONMENT`: `dev_local`
* `DEVNAME`: the current user name
* `SITE_DOMAIN` and `SITE_PROTOCOL`: The URL where the application will be
accessible to the outside world if it listens on port 8000 locally.
* Any environment variables from configured services.
* All variables under `environment` (e.g. `environment.FOO` will be passed in
as `FOO`).

The services to provide to the application are taken from the `services` array
in the configuration file. The following services are known to Forklift:

### PostgreSQL

Provides access to the database. The environment variable, `DB_DEFAULT_URL`,
contains a [Database URL][dj-database-url] for the application to use.

By default, Forklift checks if there is a PostgreSQL server running on the
machine, and if yes, provides the application with its details, taking the
current directory name for the database name.

The following parameters can be overridden: `host`, `port`, `user`, `password`,

### Elasticsearch

Provides an URL to access Elasticsearch at as environment variables
`ELASTICSEARCH_URLS` (the `|`-separated list of URLs to try at round robin)
and `ELASTICSEARCH_INDEX_NAME` (the index to use).

By default, the localhost is checked for a running instance of Elasticsearch
and if successful, the current directory name is provided to use as the index.

The following parameters can be overridden: `urls`, `index_name`.

### HTTP Proxy

Provides an HTTP proxy as an URL in `HTTP_PROXY`.

The following parameters can be overridden: `host`, `port`.

### Email (SMTP)

Provides an MTA for the application to connect to.

Defaults to `localhost` port 25.

The following parameters can be overridden: `host`, `port`.

### Logging (syslog)

Provides a syslog instance to log events to.

If not overridden, Forklift will start a daemon to print out all messages to
standard output and provide its address to the application.

The following parameters can be specified: `host`, `port`, `proto` (`tcp` or


Forklift has a hierarchy of configuration options. For example, `services`
parameter is an array of services the application need, `environment` is a
dictionary of extra environment variables to provide, `postgresql` overrides
options for PostgreSQL service, etc.

Every parameter value is searched, in order, in the following locations:

* Command line, e.g. `--driver direct` or `--postgres.port 5433` (note the
nested parameter syntax).
* User configuration file in `forklift/PROJECT.yaml`, where `PROJECT` is the
base name of the current directory, inside the
[XDG configuration directory][xdg] (usually `$HOME/.config`).
* Project configuration file - `forklift.yaml` in the current directory.

This allows granular overriding of the (hopefully useful) Forklift defaults.
For example, if the local database requires a password, it can be stored
in a local configuration file, e.g. `$HOME/.config/forklift/myapp.yaml`:

password: l@m3password

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