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ChromiumOS local trybots


The local trybot allows you to emulate a buildbot run on your local machine with a set of your changes. The changes are patched to tip of tree (TOT). They should be very similar to remote tryjobs in most regards.

For Google developers, please also take a look at the Remote Trybot documentation.

NOTE: The first time you run the trybot it will sync down a fresh checkout of the source, build a new chroot and board, which will make the initial run take longer than subsequent runs. An incremental run with an existing board takes 30min-40min.

Pre-instructions (These are important!)

  1. Make sure you’ve read through the ChromiumOS Developer Guide and can kick off a build properly.
  2. Modify your sudo config If you are at Google, you need to follow these instructions first (Under 'Tweaking with /etc/sudoers' section).
  3. Run sudo apt install qemu-kvm pbzip2 zip.
  4. Run sudo apt upgrade.
  5. Run gclient from outside the chroot to update depot_tools.
  6. If you haven’t rebooted your computer in a while, reboot it now after updating.

Verifying the Trybot

It’s good to first verify things are working properly with your system setup.

To do so, run the following from within your repo source checkout:

  1. Run repo sync to get latest version of trybot.
  2. Run cros tryjob --local amd64-generic-full-tryjob to do a test run with the current TOT. Everything should pass.

Instructions For Using the Trybot

Run the following from within your repo source checkout:

  1. Run repo sync to get latest version of cros trybot.
  2. Run cros tryjob --list to see a list of configs to run with. Add additional arguments to filter, such as cros tryjob --list release

To patch in a gerrit CL

3a. Run

cros tryjob --local -g '[*]<cl_1> [*]<cl_2> .. [*]<cl_N>' config

Substitute <config> with your desired config. Prepend a '*' to the CL ID to indicate it's an internal CL. The CL ID can be a Gerrit Change-ID or a change number.

An example:

cros tryjob --local -g I5bed88effd9c4c26885f8c75da1ec2499c4b74c8 -g 12345 -g *4168 amd64-generic-full-tryjob

This example patches in three CLs:

  1. an external CL using Gerrit change-ID (unabbreviated commit hash)
  2. an external CL using Gerrit CL number
  3. internal CL using Gerrit CL number. In case a CL has several patchsets associated with it, the latest patchset is used.

To patch in multiple CLs, you can pass all CL numbers in a quoted, space-delimited string, or specify the -g argument multiple times.

To patch in a local change

3c. Run

cros tryjob -p '<project1>[:<branch1>]...<projectN>[:<branchN>]' config

Specify the name of the project (not the path) and optionally the project branch. If no branch is specified the current branch of the project will be used.

NOTE: To get the project name of the project you're working on run repo list.

NOTE: Do not do development within the trybot buildroot! Your changes will get wiped out on the next trybot run. Develop within your source root, and patch in changes.

NOTE: Use the --nosync option to prevent the trybot from updating its source checkout. See the Tips section below for more info.

NOTE: Per the output of cros tryjob --help, the -p option is known to be buggy and -g is preferred for specifying patches. Note that -g requires the specified change to be uploaded to Gerrit.

Sample Trybot Run

$ cros tryjob --local -g 'I5bed88effd9c4c26885f8c75da1ec2499c4b74c8 4168' -p 'chromiumos/chromite chromiumos/platform/crosutils' amd64-generic-asan-tryjob

WARNING: Using default directory /usr/local/google/home/ldap/trybot as buildroot

Do you want to continue (yes/NO)? yes

INFO: Saving output to cbuildbot.log file

[sudo] password:

NOTE: The output of the trybot is automatically saved to a cbuildbot.log file in <trybot_root>/cbuildbot_logs. The log directory is printed out at the end of a run.

Overview of Trybot Operation

The first time you run the trybot, it will sync down its own checkout of the source, and build its own chroot. The CL's you specify to patch are patched to the trybot's own source tree.

When you specify local changes to patch (by specifying a project and branch the changes are on) the trybot will generate git patch files based on those changes and apply the patch files to its private source checkout.

When you specify a Gerrit changelist, the trybot will look up the changelist info from Gerrit, fetch the ref of the change, and rebase it to TOT in its private source checkout.


Thanks for using the trybot! Please contact for any issues you run into. Please report any bugs you find, and file feature requests. There will be active development on the trybot, so please sync to the latest version before you run it.