Example for cleaning up stale versions of an AppEngine project.

config.yaml

  cleanup-stale-versions:
    docker:
      - image: google/cloud-sdk
    working_directory: ~/repo/app
    steps:
      - run:
          command: |
            set +e
            echo $GCLOUD_SERVICE_KEY | base64 -d > ${HOME}/gcloud-service-key.json
            gcloud auth activate-service-account --key-file=${HOME}/gcloud-service-key.json
            gcloud config set project my-project
            echo 'Delete unused versions (those without traffic)...'
            deleteVersions=$(gcloud app versions list --project my-project --service default --format='csv[no-heading](id)' --filter='traffic_split:0' || true | tr '\n' ' ')
            [ -n "$deleteVersions" ] && gcloud app versions delete --project my-project --service default --quiet ${deleteVersions} || true

scheduled-cleanup-of-stale-versions:
    triggers:
      - schedule:
          cron: "0 0 * * *"
          filters:
            branches:
              only:
                - master
    jobs:
      - cleanup-stale-versions