PullDocker 0.1.0

Watch git repositories for Docker compose configuration changes

PullDocker

Description: Watch git repositories for Docker compose configuration changes

Copyright: 2024 Fabio Castelli (Muflone) [e-mail]

License: GPL-3+

Source code: https://github.com/muflone/pulldocker

Documentation: http://www.muflone.com/pulldocker/

Description

PullDocker is a command line tool monitor a git repository for changes and run docker deploy (and optionally others commands) when changes are detected.

This tool comes handy to automate Docker compose deployments on git operations (gitops) and can automatically deployments every time a repository receives updates or a new tag is made.

System Requirements

• Python 3.x
• PyYAML 6.0.x (https://pypi.org/project/PyYAML/)
• GitPython 3.1.x (https://pypi.org/project/GitPython/)

Usage

PullDocker is a command line utility and it requires some arguments to be passed:

pulldocker --configuration <YAML FILE> [--verbose] [--quiet]

The argument --configuration refers to a YAML configuration file containing repositories specifications (see below).

The argument --verbose will show additional debug messages for diagnostic purposes.

The argument --quiet will hide every diagnostic messages showing only errors.

YAML Configuration specifications

A YAML configuration file consists of one or more repositories, separated using --- and a newline. A repository will require the following minimum arguments:

NAME: Repository name
REPOSITORY_DIR: <Path where the git repository is cloned and can be pull>
REMOTES:
  - Remotes list from where to pull the new commits

Some more advanced specifications can be found below.

Minimal example file

NAME: PullDocker
REPOSITORY_DIR: /home/muflone/pulldocker.git
REMOTES:
  - origin

The previous example would monitor the /home/muflone/pulldocker.git repository and it will pull new commits from the remote called origin.

Whenever a new commit is found, a new docker compose up -d command will be issued in the repository directory.

Multiple repositories specifications

Multiple repositories can be configured in the same YAML file and they will be monitored one after the other, sequentially.

A multi-repository file could be the following:

NAME: PullDocker
REPOSITORY_DIR: /home/muflone/pulldocker.git
REMOTES:
  - origin
---
NAME: PixelColor
REPOSITORY_DIR: /home/muflone/pixelcolor.git
REMOTES:
  - github

The first repository will monitor the origin remote and the second repository will monitor the github remote.

Additional YAML specifications

The following YAML specifications

NAME: Repository name
REPOSITORY_DIR: <Path where the git repository is cloned and can be pull>
REMOTES:
  - origin
  - github
  - gitlab
TAGS: '*'
COMPOSE_FILE: docker/docker-compose.yaml
DETACHED: true
BUILD: true
RECREATE: true
COMMAND: docker compose -f docker/docker-compose.yaml up -d
BEGIN:
  - bash -c 'echo BEGIN ${DATE} ${TIME}'
BEFORE:
  - bash -c 'echo BEFORE ${DATE} ${TIME}'
  - bash -c 'echo ${TAG} ${TAG_HASH} ${TAG_DATE} ${TAG_TIME}'
AFTER:
  - bash -c 'echo AFTER ${DATE} ${TIME}'
  - bash -c 'echo ${TAG} ${TAG_HASH} ${TAG_DATE} ${TAG_TIME}'
END:
  - bash -c 'echo END ${DATE} ${TIME}'

The TAGS argument can be used to deploy the update only when the latest commit matches a tag. The tag specification can be '*' to indicate any tag available or a regex (Regular expression) can be used to match the available tags. For example the following: TAGS: '0\.[1-9]\.*' will only match the tags starting with 0.1.x up to 0.9.x and it would exclude the tags with 0.0.x.

If no tags are specified, any available commit newer than the current commit will issue the deploy.

The COMPOSE_FILE argument is used to specify the path for a docker-compose.yaml/yml file in the case the file is contained in another directory or it has a different name than the default docker-compose.yaml.

The DETACHED argument is used to specify a boolean value for running the docker compose in detached mode (the default, passing true) or without the detached mode, by specifying the value false.

The BUILD argument is used to build the images before starting the deploy.

The RECREATE argument is used to force the recreate the containers even if the configuration wasn't changed.

The COMMAND argument can be used to specify the explicit command for the deploy, instead of using docker compose up. This command will override any previous COMPOSE_FILE, DETACHED, BUILD arguments.

The BEGIN argument can be a list of commands to execute when checking the status for the repository, regardless if it has updates or not. Multiple commands can be specified.

The BEFORE argument can be a list of commands to execute after checking the status for the repository, before the deploy is done if it has updates. Multiple commands can be specified.

The AFTER argument can be a list of commands to execute after checking the status for the repository, after the deploy is done if it has updates. Multiple commands can be specified.

The END argument can be a list of commands to execute after checking the status for the repository, regardless if it has updates or not. Multiple commands can be specified.

Commands details

The commands arguments can use both strings (one command per line) or list of arguments (one argument per line) using the YAML lists syntax.

The following are both valid:

BEGIN:
  - bash -c 'echo BEGIN ${DATE} ${TIME}'

Using the list syntax:

BEGIN:
  -
    - bash
    - -c
    - 'echo BEGIN ${DATE} ${TIME}'

Command variables

The following special variables can be used in any command to replace the variable with its value:

• ${DATE}: current date with the format YYYY-MM-DD
• ${TIME}: current time with the format HH:mm:ss

The following variables can only be used for the COMMAND, BEFORE and AFTER arguments when the TAGS argument is used so their values will refer to the matching tag used:

• ${TAG}: tag name
• ${TAG_HASH}: commit hash for the matching tag
• ${TAG_AUTHOR}: commit author for the matching tag
• ${TAG_MESSAGE}: tag message
• ${TAG_SUMMARY}: commit message for the matching tag
• ${TAG_DATE}: tag date with the format YYYY-MM-DD
• ${TAG_TIME}: tag time with the format HH:mm:ss