git-build.sh

Lightweight, KISS system to start tasks that depend on a remote git project. Depending on your needs, git-build.sh can:

• check updates for one or more repositories, and start corresponding tasks if there was any update (git-build.sh [tasks])
• run one or more local tasks, whether there were updates or not (git-build.sh -f [tasks])
• use task settings, or for host-specific settings

Setup

Simply place git-build.sh in your $PATH. If you want git-build.sh to install itself (via the autoupdater), you can cp .git-build.sh ~/.git-build.sh && ./git-build.sh which will create ~/bin/, add it to your $PATH in ~/.bashrc, and keep git-build.sh updated in the future.

Usage

git-build.sh looks up your ~/.git-build/ to find tasks to run. A task t is defined by a t.source file containing a git remote, and a t executable file that will be run on updates to the corresponding repository.

A task may also have the following optional files:

• t.branch: checkout the specified branch on the repository
• t.host: only run the task on a specific host, see multihost setup

TLDR: a task t needs t (executable) and t.source, and accepts t.branch and t.host

Running tasks

Simply running git-build.sh will update task repositories, and run tasks which received updates. When positional arguments are passed to git-build.sh, only the corresponding tasks are triggered. For example, git-build.sh foo bar will only check updates for tasks foo and bar, and run them if updates were found.

Additionally, git-build.sh can take a -f or --force flag which triggers task runs even when no updates were found. This flag is useful when you want to trigger a task which failed because of side-effects outside of the reach of git-build.sh, such as a missing package on the system. Similarly to without the -f flag, you can give git-build.sh a specific list of tasks to trigger.

Note: Please remember to make your task scripts executable! chmod +x is your friend.

Logging

Task output is stored in t.log for STDOUT, and t.err for STDERR. These files are removed on a task run, so that they always contain information about the last build.

If your task respects STDOUT/STDERR convension, you can simply check the size of t.err to figure out whether a task failed. If some people would want that, we could further track task progress/errors and/or introduce configurable loglevels.

Configuration

Some tasks may need additional settings in order to run. A website building task may wish to know about a base URL and a destination folder, for instance. Such information may be placed in the ~/.git-build/config/ folder.

Any task receives the $GITBUILDCONF environment variable pointing to this repository, unless specific host configuration is found, as will be explained in the next section.

Multihost setup

The distinctive feature of git-build.sh is the host-based configuration system. If a folder matching $HOSTNAME is found in your ~/.git-build/, this folder will be passed to the task as $GITBUILDCONF, instead of the default configuration folder. If no host-specific configuration is found, the default configuration is used as explained previously.

Additionally, tasks can be configured to always/never run on a specific host. To run a task t on a single host, place a t.host file containing the target $HOSTNAME in ~/.git-build/. To ignore a task on a specific host, place an empty t.ignore file in ~/.git-build/$HOSTNAME/.

For an example of a multi-host setup, you can check out my own ~/.git-build.

Building your own task

To build your own task, you simply need an executable program. If your task executable is a script, don't forget to add the shebang (eg #! /bin/bash) at the top of your script or it will fail. Please ensure your task is executable (chmod +x t) or it will fail.

A task can be any program in any language, that takes exactly one positional argument containing the task name, and an environment variable called $GITBUILDCONF containing the current configuration directory, which is either ~/.git-build/$HOSTNAME or ~/.git-build/config (in this order).

Here's an example simple task that writes the current time to ~/.git-build/t.log and appends random characters to another file:

#! /bin/bash

date # STDOUT is automatically appended to task log

hexdump -n 16 -e ' /1 "%02x"' /dev/urandom >> ~/random.list

Note: The task name is passed to the task because the task may be a symlink to a program located somewhere else on the system. This is further described in the Shared build scripts section.

Advanced usage

Shared build scripts

A script for multiple tasks

Ordering tasks

Auto-updater example and lockfile mechanisms

Versioning

Keeping your ~/.git-build in git \o/

Auto-run tasks

Auto-triggering updates/builds is beyond the scope of this project! You should consider using standard cronjobs for that.

I'm also interested in running this script through a webhook endpoint for Github/Gitlab/Gitea webhooks, in order to build a simple and reliable CI/CD system. This is not implemented yet and will not be part of this repository, but i will update this README when a such solution is available. If you want to contribute this feature in the meantime, you are more than welcome!

Auto-update

Yes, you read that correctly! The .git-build/git-build{,.source} task provided in this repository is a proof-of-concept autoupdater that will download and install git-build.sh updates on every run.

It's a terrible idea for security to autoupdate executables in your $PATH and you probably do not want to do that. But i thought it was a nice demo and it can be useful for people new to the command-line, although this project should not receive too many updates in the future as it is already doing what it is supposed to.

Contribute

Right now the state of this project is "works for me". It could be useful for other people which is why i just spent a full hour writing this README. However, there could be ways in which git-build.sh fails you!

If a feature is missing for you, or you encounter a bug, please report it on tildegit (requires an account on a tildeverse server) or send a mail to southerntofu (@) thunix.net. If you can contribute the feature or fix the bug yourself, your patches are welcome!

This project abides by the ~fr operating principles.