Container images for container source code present in cos/tools are built utilizing the Google cloud build service. An automated build system which utilizes cloud build triggers builds the container images whenever changes are pushed on the cos/tools git repo. Any change to the container images source code automatically triggers new builds for all the containers in this repo.
For each new build executed by the automated triggers, the built container images are pushed to an internal google container image registry with unique tag labels which are the GIT commit sha of the change being updated.
The release process is a multi-party code reviewed automated process(see source here). This is also achieved by using the cloud build triggers on the cos/tools repository. The release candidates (state of the releases) live in a config file(source). When changes are made to the release candidates, an automated cloud build process copies the specified container images from the internal google container image registry to the public cos-cloud container registry.
After making changes to the release state the validity of the changes can be checked by running the following command from the root of the repo:
gcloud builds submit --config=presubmit.yaml
where presubmit.yaml could look like the following:
steps: - name: 'gcr.io/google.com/cloudsdktool/cloud-sdk:latest' entrypoint: 'bash' args: ['-c', 'pip3 install -r release/requirements.txt && python3 release/release.py --verify' ]