A tool to wait for services and execute command. Useful for Docker containers that depend on slow to start services (like almost everything).
Project description
A tool to wait for services and execute command. Useful for Docker containers that depend on slow to start services (like almost everything).
Free software: BSD 2-Clause License
Installation
Currently holdup is only published to PyPI and hub.docker.com.
To install from PyPI:
pip install holdup
It has no dependencies except the optional PostgreSQL check support, which you’d install with:
pip install 'holdup[pg]'
You can also install the in-development version with:
pip install https://github.com/ionelmc/python-holdup/archive/master.zip
Alternate installation (Docker image)
Example:
docker run --rm ionelmc/holdup tcp://foobar:1234
Note that this will have some limitations:
executing the command is pretty pointless because holdup will run in its own container
you’ll probably need extra network configuration to be able to access services
you won’t be able to use docker run inside a container without exposing a docker daemon in said container
Usage
usage: holdup [-h] [-t SECONDS] [-T SECONDS] [-i SECONDS] [-n] service [service …] [– command [arg [arg …]]]
Wait for services to be ready and optionally exec command.
- positional arguments:
- service
A service to wait for. Supported protocols: “tcp://host:port/”, “path:///path/to/something”, “unix:///path/to/domain.sock”, “eval://expr”, “pg://user:password@host:port/dbname” (“postgres” and “postgresql” also allowed), “http://urn”, “https://urn”, “https+insecure://urn” (status 200 expected for http*). Join protocols with a comma to make holdup exit at the first passing one, eg: “tcp://host:1,host:2” or “tcp://host:1,tcp://host:2” are equivalent and mean any that pass.
- command
An optional command to exec.
- optional arguments:
- -h, --help
show this help message and exit
- -t SECONDS, --timeout SECONDS
Time to wait for services to be ready. Default: 60.0
- -T SECONDS, --check-timeout SECONDS
Time to wait for a single check. Default: 1.0
- -i SECONDS, --interval SECONDS
How often to check. Default: 0.2
- -v, --verbose
Verbose mode.
- --verbose-passwords
Disable PostgreSQL/HTTP password masking.
- -n, --no-abort
Ignore failed services. This makes holdup return 0 exit code regardless of services actually responding.
- --insecure
Disable SSL Certificate verification for HTTPS services.
- --version
display the version of the holdup package and its location, then exit.
Example:
holdup tcp://foobar:1234 -- django-admin ...
Documentation
Development
To run all the tests run:
tox
Note, to combine the coverage data from all the tox environments run:
Windows |
set PYTEST_ADDOPTS=--cov-append tox |
|---|---|
Other |
PYTEST_ADDOPTS=--cov-append tox |
Changelog
5.1.0 (2024-04-12)
Fixed buggy handling when http checks are specified with a port.
Changed User-Agent header and stripped port from Host header for http checks.
Refactored a bunch of code into a separate holdup.checks module.
5.0.0 (2024-04-11)
Added a static binary in the Github release (built with Pyinstaller on Alpine, as a static bin).
Dropped support for Python 3.7 and added in Python 3.12 in the test suite.
4.0.0 (2023-02-14)
Added support for psycopg 3 (now the holdup[pg] extra will require that). The old psycopg2 is still supported for now.
Dropped support for Python 3.6 and added in Python 3.11 in the test suite.
3.0.0 (2022-03-20)
Dropped support for Python 2.
Switched CI from Travis to GitHub Actions.
Fixed bugs with password masking (it wasn’t working for postgresql URIs).
2.0.0 (2021-04-08)
Added support for password masking (--verbose-passwords to disable this feature).
Overhauled checks display a bit, output might be slightly different.
Added support for basic and digest HTTP authentication.
Published Docker image at https://hub.docker.com/r/ionelmc/holdup (Alpine based).
1.9.0 (2021-01-11)
Added a --version argument.
Changed verbose output to mask passwords in postgresql checks.
1.8.1 (2020-12-16)
Add support for PostgreSQL 12+ clients (strict integer type-checking on connect_timeout). The float is now converted to an integer.
1.8.0 (2019-05-28)
Added a PostgreSQL check. It handles the the database system is starting up problem. Contributed by Dan Ailenei in 6.
Changed output so it’s more clear and more brief:
arguments (checks) are quoted when printed,
“any” checks give exact info about what made it pass,
repetitive information is removed.
Simplified the internals for the “AnyCheck”.
1.7.0 (2018-11-24)
Added support for skipping SSL certificate verification for HTTPS services (the --insecure option and https+insecure protocol). Contributed by Mithun Ayachit in 2.
1.6.0 (2018-03-22)
Added verbose mode (-v or --verbose).
Changed default timeout to 60s (from 5s).
1.5.0 (2017-06-07)
Added an eval://expression protocol for weird user-defined checks.
1.4.0 (2017-03-27)
Added support for HTTP(S) check.
1.3.0 (2017-02-21)
Add support for “any” service check (service syntax with comma).
1.2.1 (2016-06-17)
Handle situation where internal operations would take more than planned.
1.2.0 (2016-05-25)
Added a file check.
1.1.0 (2016-05-06)
Removed debug print.
Added --interval option for how often to check. No more spinloops.
1.0.0 (2016-04-22)
Improved tests.
Always log to stderr.
0.1.0 (2016-04-21)
First release on PyPI.
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