Automatically delete stale AppEngine versions with CircleCI

config.yml

# Javascript Node CircleCI 2.0 configuration file
#
# Check https://circleci.com/docs/2.0/language-javascript/ for more details
#
version: 2
jobs:
  cleanup-stale-qa-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 $GCP_PROJECT
            echo 'Delete unused frontend versions (those without traffic)...'
            deleteFrontendVersions=$(gcloud app versions list --project $GCP_PROJECT --service default --format='csv[no-heading](id)' --filter='traffic_split:0' || true | tr '\n' ' ')
            [ -n "$deleteFrontendVersions" ] && gcloud app versions delete --project $GCP_PROJECT --service default --quiet ${deleteFrontendVersions} || true
            echo 'Delete unused backend versions (those without traffic)...'
            deleteBackendVersions=$(gcloud app versions list --project $GCP_PROJECT --service backend --format='csv[no-heading](id)' --filter='traffic_split:0' || true | tr '\n' ' ')
            [ -n "$deleteBackendVersions" ] && gcloud app versions delete --project $GCP_PROJECT --service backend --quiet ${deleteBackendVersions} || true

workflows:
  version: 2

  scheduled-cleanup-of-stale-qa-versions:
    triggers:
      - schedule:
          cron: "0 0,2,4,6,8,10,12,14,16,18,20,22 * * *"
          filters:
            branches:
              only:
                - master
    jobs:
      - cleanup-stale-versions