User:Mjzffr/Resources/Mozharness

What is mozharness?

• It's a collection of Python modules that make it easy to extend and configure common automation tasks
  • (Henrik) It's mostly all configuration driven
• Lives in mozilla-central under testing/mozharness: http://hg.mozilla.org/mozilla-central/file/default/testing/mozharness
• Logging and config management (and much more) are already taken care of for you
• Nice things: cross-platform, platform-specific configs, make it easy to create reproducible environment

How do I write a mozharness script? Some tips

• See Resources below
• Get mozharness without checking out all of mozilla-central (See archiver_client.py below)
  • (Henrik) I would still propose to use mozilla-central or inbound if the target is to land the script in tree
• Get your script to find mozharness (especially if your script lives in another repo, not in-tree): e.g. https://gist.github.com/mjzffr/f2c7612d2efd3c0c1304#file-firefox_media_tests_jenkins-py-L30
• Your script will probably consist of a class that extends BaseScript or VirtualenvMixin + config
• Use multiple inheritance to plug-in the behaviour you need, then customize. Some examples:
  • VirtualenvMixin - create virtualenvs, manage dependencies
  • TestingMixin - obtain firefox binary, tests, symbols
  • VCSToolsScript - check out hg or git repositories
  • Lots more here: http://hg.mozilla.org/mozilla-central/file/default/testing/mozharness/mozharness
• Be careful: if your mozharness script creates a virtual env, you don't want to run it inside your own virtual env

How do I use mozharness scripts in my Jenkins instance?

• Disclaimer: This is just how we set things up on pf-jenkins. There are other ways.
• Use archiver_client.py to put mozharness on your builders (see below)
• Set an environment variable with the path to mozharness on the builders (in our case MOZHARNESSHOME)
• Jenkins job checks out Github repo that contains our mozharness script (Note: our project will soon move from Github to mozilla-central)
• mozharness script is called in build step

References

• https://wiki.mozilla.org/ReleaseEngineering/Mozharness (includes tutorial and simple examples)
• Ask questions on #releng - jlund, armenzg
• Could also ask on #ateam although we don't own mozharness - most recent users are maja_zf, whimboo, armenzg, and others)
• More examples:
  • firefox-ui-tests running in mozmill-ci (Jenkins): http://hg.mozilla.org/mozilla-central/file/default/testing/mozharness/scripts/firefox_ui_tests
  • firefox-media-tests running per-commit in buildbot: http://hg.mozilla.org/mozilla-central/file/default/testing/mozharness/scripts/firefox_media_tests_buildbot.py
    • for running tests on our Jenkins instance and also taking care of Treeherder submission https://gist.github.com/mjzffr/f2c7612d2efd3c0c1304#file-firefox_media_tests_jenkins-py (Note: we'll eventually remove Treeherder submission from this script because it will be taken care of by TaskCluster)

archiver_client example

1. Download archiver_client: http://hg.mozilla.org/build/tools/file/default/buildfarm/utils/archiver_client.py

2. Run something like `python archiver_client.py mozharness --rev 62cd40885e93` and it will download to ./mozharness

More: https://api.pub.build.mozilla.org/docs/usage/archiver/