Awesome

NOTE (2021):

This project is only very moderately maintained and mostly dormant (though not obsolete -- it's still used daily). It was originally developed for use early in the Rust project's life, and has been superseded by multiple enhanced rewrites:

• Homu: https://github.com/barosl/homu
• Fork of Homu that Rust uses: https://github.com/rust-lang/homu
• Bors-NG: https://bors.tech/ / https://github.com/bors-ng/bors-ng

I will periodically accept PRs and such for minor compatibility issues or blockers to keep it running, but in general future feature-work or development of the lineage should go to one of the successor projects.

Bors is an automated integrator for github and buildbot.

It's written for the rust project, so probably contains a number of peculiarities of this project. You may need to do some work to reuse it elsewhere.

We assume bors is run in a loop, perhaps once per minute from cron (github has a rate-limited API). Each time it runs it reloads its entire state from github and buildbot, decides what the most fruitful next-thing it can do is, does that one thing, and exits. This is a crude design but it means the script and workspace is mostly stateless and should (once debugged) never require operator intervention in the workspace driving it, only sometimes on the sites it reads from (github and buildbot).

It requires a config file, bors.cfg, in its workspace. This config file should hold the a json dictionary:

 {
       "owner": "<github-username-the-owner-of-repo>",
       "repo": "<short-github-repo-name>",
       "reviewers": ["<user1>", "<user2>", ...],
       "builders": ["<buildbot-builder1>", "<buildbot-builder2>", ...],
       "test_ref": "<git-ref-for-testing>",
       "master_ref": "<git-ref-for-integration>",
       "nbuilds": <number-of-buildbot-builds-history-to-look-at>,
       "buildbot": "<buildbot-url>",
       "gh_user": "<github-user-to-run-as>",
       "gh_pass": "<password-for-that-user>"
 }

For example, the rust config at the time of writing (minus password) is:

 {
       "owner": "mozilla",
       "repo": "rust",
       "reviewers": ["brson", "catamorphism", "graydon", "nikomatsakis", "pcwalton"],
       "builders": ["auto-linux", "auto-win", "auto-bsd", "auto-mac"],
       "test_ref": "auto",
       "master_ref": "incoming",
       "nbuilds": 5,
       "buildbot": "http://buildbot.rust-lang.org",
       "gh_user": "bors",
       "gh_pass": "..."
 }

The general cycle of bors' operation is as follows:

• load all pull reqs

• load all statuses and comments

• sort them by the STATE_* values below

• pick the ripest (latest-state) one and try to advance it, meaning:

  • if state==UNREVIEWED or DISCUSSING, look for r+ or r-:

    • if r+, set APPROVED
    • if r-, set DISAPPROVED
    • (if nothing is said, exit; nothing to do!)

  • if state==APPROVED, merge pull.sha + master => test_ref:

    • if merge ok, set PENDING
    • if merge fail, set ERROR (pull req bitrotted)

  • if state==PENDING, look at buildbot for test results:

    • if failed, set FAILED
    • if passed, set TESTED
    • (if no test status, exit; waiting for results)

  • if state==TESTED, fast-forward master to test_ref

    • if ffwd works, close pull req
    • if ffwd fails, set ERROR (someone moved master on us)

License

Copyright 2013 Mozilla Foundation.

Licensed under the Apache License, Version 2.0 or the MIT license, at your option. These files may not be copied, modified, or distributed except according to those terms.