Hoff

Hoff is a bot for GitHub that enforces a clean history, and ensures that master always builds.

Note, there is a more active fork at https://github.com/channable/hoff.

Hoff intends to replace the merge button in the GitHub UI. Unlike GitHub* and many other tools, Hoff integrates changes into master using a rebase. This keeps the history clean, free of random fork points and merge commits. (TODO: In the future Hoff will also enforce a commit message format.)

* This is no longer true.

Furthermore, Hoff implements the Not Rocket Science Principle of software engineering:

Automatically maintain a repository of code that always passes all the tests.

The application watches a repository for new pull requests. Once a pull request has been approved (through an LGTM comment left by a reviewer), it integrates the changes into master, and pushes those to a testing branch. When CI reports a successful build for this branch, master is forwarded to it. If the build fails, the commits never make it into master, keeping the build green at all times.

Installing

See the installation guide if you want to run a self-hosted version of Hoff.

TODO: Write a proper guide to build a package. TODO: Publish official deb packages?

Building

Hoff is written in Haskell and builds with Stack:

$ stack setup
$ stack build
$ stack test

To run the application locally:

$ cp package/example-config.json config.json
$ stack exec hoff config.json

You probably want to edit the config file before running.

To run Hoff on a server, you can build a self-contained squashfs file system image with Nix:

$ nix build --out-link hoff.img
$ cp package/example-config.json config.json
$ sudo systemd-nspawn \
  --ephemeral         \
  --image hoff.img    \
  --bind-ro=$PWD:/etc \
  -- /usr/bin/hoff /etc/config.json

The image includes Hoff and all of its dependencies (Git, SSH). You can run it with systemd. TODO: Make it work with portablectl.

Further reading

More information is available in the doc directory:

• Background: My original intention was more ambitious than building a GitHub bot. This document gives some background about what I want to build.
• Approach: Progress is made in many small steps. This document outlines the current goals.
• Design: Outlines the architecture of the application.
• Installing: The installation guide.

License

Hoff is free software. It is licensed under the Apache 2.0 license. It may be used both for commercial and non-commercial use under the conditions given in the license.