Flutter's Build Infrastructure

This directory exists to support building Flutter on our build infrastructure.

The results of such builds are viewable at:

The LUCI infra requires permissions to retrigger or schedule builds. Contact @kf6gpe or another Google member of the Flutter team if you need to do that.

The Cirrus-based bots run the test.dart script for each PR and submission. This does testing for the tools, for the framework, and (for submitted changes only) rebuilds and updates the master branch API docs staging site. For tagged dev and beta builds, it also builds and deploys the gallery app to the app stores. It is configured by the .cirrus.yml.

We also have post-commit testing with actual devices, in what we call our devicelab.

LUCI (Layered Universal Continuous Intergration)

A set of recipes are run on Windows, Linux, and Mac machines. The configuration for how many machines and what kind are managed internally by Google. Contact @kf6gpe or another Google member of the Flutter team if you suspect changes are needed there. Both of these technologies are highly specific to the LUCI project, which is the successor to Chromium‘s infra. We’re just borrowing some of their infrastructure.

Prerequisites

To work on this infrastructure you will need:

  • depot_tools
  • Python package installer: sudo apt-get install python-pip
  • Python coverage package (only needed for training_simulation): sudo pip install coverage

To run prepare_package.dart locally:

  • Make sure the depot_tools is in your PATH. If you're on Windows, you also need an environment variable called DEPOT_TOOLS with the path to depot_tools as value.
  • Run gsutil.py config (or python %DEPOT_TOOLS%\gsutil.py on Windows) to authenticate with your auth token.
  • Create a local temp directory. cd into it.
  • Run dart [path to your normal Flutter repo]/dev/bots/prepare_package.dart --temp_dir=. --revision=[revision to package] --branch=[branch to deploy to] --publish.
  • If you're running into gsutil permission issues, check with @Hixie to make sure you have the right push permissions.

Getting the code

The following will get way more than just recipe code, but it will get the recipe code:

mkdir chrome_infra
cd chrome_infra
fetch infra

More detailed instructions can be found here.

Most of the functionality for recipes comes from recipe_modules, which are unfortunately spread to many separate repositories. After checking out the code search for files named api.py or example.py under infra/build.

Editing a recipe

Flutter has one recipe per repository. Currently flutter/flutter and flutter/engine:

  • build/scripts/slave/recipes/flutter/flutter.py
  • build/scripts/slave/recipes/flutter/engine.py

Recipes are just Python with some limitations on what can be imported. They are documented by the luci/recipes-py github project.

The typical cycle for editing a recipe is:

  1. Make your edits (probably to files in //chrome_infra/build/scripts/slave/recipes/flutter).
  2. Update the tests. Run build/scripts/slave/recipes.py test train to update existing expected output to match the new output. Verify completely new test cases by altering the GenTests method of the recipe. The recipe is required to have 100% test coverage.
  3. Run led get-builder 'luci.flutter.prod:BUILDER_NAME' | led edit -p 'revision="GIT_HASH"' | led edit-recipe-bundle | led launch, where BUILDER_NAME is the builder name (e.g. Linux Engine), and GIT_HASH is the hash to build (which is important for the engine but not for the framework).
  4. To submit a CL, you need a local branch first (git checkout -b [some branch name]).
  5. Upload the patch (git commit, git cl upload) and send it to someone in the recipes/flutter/OWNERS file for review.

The infra config repository

The flutter/infra repository contains configuration files for the dashboard, builder groups, scheduling, and individual builders. Edits to this may require changes other internal Google repositories - e.g., to change the operating system or number of machines. If you want to do that, reach out to @kf6gpe or another member of the Google team.

Each configuration file in that repository has a link in the top comments to a schema that describes available properties.

Future Directions

We would like to host our own recipes instead of storing them in build. Support for cross-repository recipes is in-progress. If you view the git log of this directory, you‘ll see we initially tried, but it’s not quite ready.

Android Tools

The Android SDK and NDK used by Flutter's Chrome infra bots are stored in Google Cloud. During the build a bot runs the download_android_tools.py script that downloads the required version of the Android SDK into dev/bots/android_tools.

To check which components are currently installed, download the current SDK stored in Google Cloud using the download_android_tools.py script, then dev/bots/android_tools/sdk/tools/bin/sdkmanager --list. If you find that some components need to be updated or installed, follow the steps below:

How to update Android SDK on Google Cloud Storage

  1. Run Android SDK Manager and update packages $ dev/bots/android_tools/sdk/tools/android update sdk Use android.bat on Windows.

  2. Use the UI to choose the packages you want to install and/or update.

  3. Run dev/bots/android_tools/sdk/tools/bin/sdkmanager --update. On Windows, run sdkmanager.bat instead. If the process fails with an error saying that it is unable to move files (Windows makes files and directories read-only when another process is holding them open), make a copy of the dev/bots/android_tools/sdk/tools directory, run the sdkmanager.bat from the copy, and use the --sdk_root option pointing at dev/bots/android_tools/sdk.

  4. Run dev/bots/android_tools/sdk/tools/bin/sdkmanager --licenses and accept the licenses for the newly installed components. It also helps to run this command a second time and make sure that it prints “All SDK package licenses accepted”.

  5. Run upload_android_tools.py -t sdk $ dev/bots/upload_android_tools.py -t sdk

How to update Android NDK on Google Cloud Storage

  1. Download a new NDK binary (e.g. android-ndk-r10e-linux-x86_64.bin)

  2. cd dev/bots/android_tools $ cd dev/bots/android_tools

  3. Remove the old ndk directory $ rm -rf ndk

  4. Run the new NDK binary file $ ./android-ndk-r10e-linux-x86_64.bin

  5. Rename the extracted directory to ndk $ mv android-ndk-r10e ndk

  6. Run upload_android_tools.py -t ndk $ cd ../.. $ dev/bots/upload_android_tools.py -t ndk

Flutter codelabs build test

The Flutter codelabs exercise Material Components in the form of a demo application. The code for the codelabs is similar to, but distinct from, the code for the Shrine demo app in Flutter Gallery.

The Flutter codelabs build test ensures that the final version of the Material Components for Flutter Codelabs can be built. This test serves as a smoke test for the Flutter framework and should not fail. If it does, please address any issues in your PR and rerun the test. If you feel that the test failing is not a direct result of changes made in your PR or that breaking this test is absolutely necessary, escalate this issue by submitting an issue to the MDC-Flutter Team.