Clone this repo:


  1. 05f68a6 Add OWNERS by Edward Lesmes · 6 weeks ago main master
  2. ee8a73e [budgets] fix regression for size info with budgets by Todd Lee · 5 months ago
  3. 37e642e [budgets] add budget/owner support for binary sizes by Todd Lee · 6 months ago
  4. b357824 [theme] support gerrit dark theme by Todd Lee · 6 months ago
  5. ad41b8d [readme] document how to test with Gerrit FE Dev Helper by Gary Miguel · 6 months ago

Binary Size Plugin for Gerrit

How it works

The plugin queries tryjobs for the current patchset on Gerrit, and gets the binary_sizes property from each of them. It also queries the equivalent CI jobs for the same base revision, and gets the same property from them. It then displays the results in a table, with rows being the files (keys in binary_sizes dict), and the columns being:

Size before | Size after | Size delta (including %) | Budget info | File | Builder

This is based on JSON output of the form:

{ “some binary name”: BINARY_SIZE_IN_BYTES, “some binary name.budget”: BINARY_SIZE_BUDGET_IN_BYTES, “some binary name.owner”: OWNER_URL, }

For example:

{ “foo”: 1024, “foo.budget”: 2048, “foo.owner”: “” “bar”: 2048, }

Note that including a *.budget item for any given binary is optional. If no budget items are provided, then the “Budget info” column will be omitted from the results table. In the event that a *.budget item is specified, an addition *.owner item can be used to provide a URL for context/ownership related to the pertinent budget item (in the UI, the budget value is clickable, taking the user to the provided URL).


This plugin is configured via the binary-size.config file present in the repo‘s refs/meta/config ref, as well as the same file in all repositories in the repo’s inheritance chain (up to and including All-Projects).

See an example of binary-size.config:

Also a short snippet below:

    git = ""
    gerrit = ""

[builder "luci.webrtc.try/linux_rel"]
    base = " Release"
    # Optional, needed if the base builder is triggered from a different repo
    # than the try builder. Assumed to be hosted on [host].git.
    baseRepo = "foo"

[builder "luci.webrtc.try/win_x64_clang_rel"]
    base = " Release (Clang)"

This contains a mapping between tryjob builders and equivalent postsubmit builders. Equivalent in the sense that if they ran with the same code, they would produce the same binary_sizes. The plugin queries builds only from buckets that are mentioned at least once. It is OK to specify builders that don't provide a binary_sizes property, they will just be ignored.

Note that populating the binary_sizes property is a separate responsibility, and it is up to you to implement in your recipes. It needs to be a dict like {"": 123456, ...}. The values of the dict are treated as sizes in bytes.

All changes to binary-size.config files are instantly reflected. There is no caching period or need to restart the server.


This plugin requires the buildbucket plugin in order to search builds. Ensure that they are both installed, or prepare to see errors in the browser's console.


git clone --recursive
cd gerrit/plugins

git clone
cd buildbucket
ln -s src/main/resources/static static  # May be unneeded in the future.
cd ..

git clone
cd binary-size

Run the polygerrit-ui server against live data

Use the script (based on polygerrit-ui/ You may change some paths by setting environment variables, for example:

# Install dependencies:
sudo apt-get install -y nodejs

GERRIT_DIR="$HOME/gerrit" ./


Manual on live Gerrit instance

You can test on a live Gerrit instance by replacing the plugin JavaScript using Gerrit FE Dev Helper.

Note: this works only for frontend (JavaScript) changes. Not for changes to the backennd (Java) code.

  1. Build the JavaScript bundle and serve it via HTTP.
cd <root of gerrit checkout>
bazel build plugins/binary-size:all
# Ensure the bundle was built
BUNDLE_PATH=$(find bazel-out/ -name binary-size-bundle.js)
cd $(dirname ${BUNDLE_PATH})
python3 -m http.server 8080
  1. Install the Gerrit FE Dev Helper Chrome extension.

  2. Navigate to a Gerrit page that you expect to show size diffs. E.g.

  3. Configure the Gerrit FE Dev Helper to redirect to your local binary-size-bundle.js. For example:

Target:, Operator: redirect, Destination: http://localhost:8080/binary-size-bundle.js

Note it may also be necessary to redirect the CDN for the polygerrit_assets to reflect changes to static html etc in the bundled plugin. You can find the appropriate URL under the “Sources” section of Chrome's developer console. It will look something like this, but possibly with a different versioning number (e.g. 426.0):

This redirect should also go to http://localhost:8080/binary-size-bundle.js

  1. Click the Gerrit FE Dev Helper button to activate it. It should reload the page.


# Install dependencies.
sudo apt-get install -y npm
npm install -g bower
npm install -g web-component-tester
cd test/
bower install

# Run the tests from the directory root.
cd ../

Note: Testing is disabled for Safari due to this issue.