Using the trybots


The trybots let committers try uncommitted patches on multiple platforms in an automated way.

  • Trybots include all platforms for which we currently build Chromium, though they may not support all configurations built on CI.
  • The commit queue (CQ) runs a subset of available trybots. See here for more information.
  • Trybots can be manually invoked via git cl try or the “Choose Tryjobs” UI in gerrit.
  • Custom trybots can be added to the list of builders triggered and checked by the CQ via the Cq-Include-Trybots commit message footer. See here for more information.
  • Any committer can use the trybots.
  • Non-committers with tryjob access can also use the trybots. See here for more information.
  • External contributors without tryjob access can ask committers to run tryjobs for them.
Warning: Please do not trigger more than ~5-10 tryjobs per builder per hour. We don‘t have enough spare capacity for more than that, and we don’t have per-user quotas yet ( to implement that).


  1. Upload your change to gerrit via git cl upload

  2. Run trybots:

    • Run the default set of trybots by starting a CQ dry run, either by setting CQ+1 on gerrit or by running git cl try with no arguments.

    • Manually run trybots of your choice by either the “Choose Tryjobs” button in gerrit or providing arguments to git cl try:

      • specify bucket name with -B/--bucket. For chromium tryjobs, this should always be luci.chromium.try
      • specify bot names with -b/--bot. This can be specified more than once.


Launching a CQ dry run:

$ git cl try

Launching a particular trybot:

$ git cl try -B luci.chromium.try -b linux-rel

Launching multiple trybots:

$ git cl try -B luci.chromium.try \
  -b android-binary-size \
  -b ios-simulator-full-configs \
  -b linux-blink-rel \
  -b win7-blink-rel
  # etc

Trying Changes in Dependencies

It is also possible to run a Chromium try job with a pending CL in a separate repository that is synced via DEPS. Normally DEPS files specify the SHA1 revision hash of the dependency. But commits that are part of pending CLs are not part of the default refspec fetched when gclient checks out the dependency. Instead, you can specify a symbolic reference to your change, like refs/changes/12/2277112/3. To determine the ref to use, click the “Download” button on the dependency CL in Gerrit, which will show it as part of several git commands. Then edit the DEPS file in Chromium.

If, for example, you wanted to test a pending V8 CL in Chromium, you would edit the DEPS line, which may look like this:

  'v8_revision': '50bc0b22b15da1410a1be6240a25a184d5896908',

And change it to:

  'v8_revision': 'refs/changes/12/2277112/3',

When you run the try job, gclient will sync in your pending CL. Note that if your pending CL is based on a revision that is either older or newer than the revision specified in DEPS, the tryjob may fail. You can rebase your CL to be on top of the same revision specified in the DEPS file to avoid this.

Bugs? Feature requests? Questions?

File a trooper bug.