Chromium Docs

Chromium Updater Developer's Manual

This manual provides information on how to develop the Chromium Updater, including tips and tricks.

Bots & Lab

NOTE: Knowledge in this section may become out-of-date as LUCI evolves quickly.

Adding Builders

  • Update files as needed:
    • testing/buildbot/waterfalls.pyl
    • infra/config/subprojects/chromium/ci/chromium.updater.star
  • Re-generate chromium.updater.json:
vpython3 .\testing\buildbot\generate_buildbot_json.py
  • (Optional) Re-format the builder definition file if necessary.
lucicfg fmt .\infra\config\subprojects\chromium\ci\chromium.updater.star
  • Generate builder property and configuration files:
lucicfg infra\config\main.star
git add .

Update builder configuration

Each builder has a configuration that governs the GN args. The mapping is defined in file tools/mb/mb_config.pyl. Steps to update the config:

Run tests on swarming

mb tool can upload your private build target (and all the dependencies, based on build rule) to swarming server and run the target on bots. The upload may take quite some time if the target changed a lot since the last upload and/or your network is slow.

  • Simple scenario:
    .\tools\mb\mb.bat run -v --swarmed .\out\Default updater_tests -- --gtest_filter=*Integration*
  • Sometimes the mb tool may fail to match the testing OS (when doing cross-compile) or you may want to run the task on certain kind of bots. This can be done by specifying bots dimension with switch -d. Remember --no-default-dimensions is necessary to avoid dimension value conflict. Example:
    .\tools\mb\mb.bat run --swarmed --no-default-dimensions -d pool chromium.win.uac -d os Windows-10 .\out\Default updater_tests_system -- --gtest_filter=*Install*
  • If your test introduces dependency on a new app on macOS, you need to let mb tool know so it can correctly figure out the dependency. Example: https://crrev.com/c/3470143.

Accessing Bots

TODO(crbug.com/1327486): Document how to remote into bots for debugging.

Updating the Checked-In Version of the Updater

An older version of the updater is checked in under //third_party/updater. This version of the updater is used in some integration tests. The updater is pulled from CIPD based on the versions specified in //DEPS. A system called 3pp periodically updates the packages in CIPD, based on a combination of the Chromium build output and what is actually released through Omaha servers. The configuration for 3pp can be found in //third_party/updater/*/3pp.

To update these copies of the updaters:

  1. Land whatever CLs need to be committed on trunk.
  2. Wait for builds to be available in CIPD that have the needed changes.
    • Instead of waiting, you can instead modify the fetch.py scripts for 3pp. For Chrome builds, make sure the build has been released in Omaha then update the fetch script with the desired version number. For Chromium, make sure the build exists in GCS (the chromium-browser-snapshots bucket), then update the min version in the script. The min version usually is different per-platform, since Chromium does not archive a version at every CL. After making these changes, 3pp will import the new versions within a few hours.
  3. Update //DEPS to point to the new versions.

Building

Cleaning the build output

Running ninja with t clean cleans the build out directory. For example:

ninja -C out\Default chrome/updater:all -t clean

Debugging

Debug into Windows update service

  • Install updater: UpdaterSetup.exe --install [--system]

TIP: Debugger may have trouble to find the symbols at the service side even if you add your build output directory to the symbol paths. To workaournd the issue, you can copy updater.exe* to the versioned installation directory.

  • Set a breakpoint at the client side after service instantiation but before calling into the service API. Most likely this will be somewhere in file update_service_proxy.*.
  • Start the client, wait for it to hit the break point. At this time, the service process should have started.
  • Find the server process, which contains the command line switch --server (user-level server) or --system --windows-service (system-level server). Start another debugger and attach the server process. Then set a server-side breakpoint at the place you want to debug.
  • Continue the client process.

How to generate the cross-compilation IDL COM headers and TLB files

6 different build flavors need to be built in sequence. If you see errors similar to the following:

midl.exe output different from files in gen/chrome/updater/app/server/win, see C:\src\temp\tmppbfwi0ds
To rebaseline:
  copy /y C:\src\temp\tmppbfwi0ds\* c:\src\chromium\src\third_party\win_build_output\midl\chrome\updater\app\server\win\x64
ninja: build stopped: subcommand failed.

You can then run the following command to update IDL COM files for all flavors:

python3 chrome/updater/tools/update_idl.py