name: Delete GCP resources

on:
  # Run daily, when most devs aren't working
  # 0700 UTC is after AEST working hours but before ET working hours
  schedule:
    - cron: "0 7 * * *"
  workflow_dispatch:

env:
  # Delete all resources created before $DELETE_AGE_DAYS days ago.
  # We keep this short to reduce storage costs.
  DELETE_AGE_DAYS: 2
  # But keep the latest $KEEP_LATEST_IMAGE_COUNT images of each type.
  # We keep this small to reduce storage costs.
  KEEP_LATEST_IMAGE_COUNT: 2

jobs:
  delete-resources:
    name: Delete old GCP resources
    runs-on: ubuntu-latest
    permissions:
      contents: 'read'
      id-token: 'write'
    steps:
      - uses: actions/checkout@v3.0.2
        with:
          persist-credentials: false

      # Setup gcloud CLI
      - name: Authenticate to Google Cloud
        id: auth
        uses: google-github-actions/auth@v0.8.1
        with:
          retries: '3'
          workload_identity_provider: 'projects/143793276228/locations/global/workloadIdentityPools/github-actions/providers/github-oidc'
          service_account: 'github-service-account@zealous-zebra.iam.gserviceaccount.com'
          token_format: 'access_token'

      # Deletes all the instance templates older than $DELETE_AGE_DAYS days.
      - name: Delete old instance templates
        run: |
          DELETE_BEFORE_DATE=$(date --date="$DELETE_AGE_DAYS days ago" '+%Y%m%d')
          TEMPLATES=$(gcloud compute instance-templates list --sort-by=creationTimestamp  --filter="name~-[0-9a-f]+$ AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')

          for TEMPLATE in $TEMPLATES
          do
            gcloud compute instance-templates delete ${TEMPLATE} || continue
          done

      # Deletes all the disks older than $DELETE_AGE_DAYS days.
      #
      # Disks that are attached to an instance template can't be deleted, so it is safe to delete all disks here.
      - name: Delete old disks
        run: |
          DELETE_BEFORE_DATE=$(date --date="$DELETE_AGE_DAYS days ago" '+%Y%m%d')

          # Disks created by PR jobs, and other jobs that use a commit hash
          COMMIT_DISKS=$(gcloud compute disks list --sort-by=creationTimestamp  --filter="name~-[0-9a-f]+$ AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')

          for DISK in $COMMIT_DISKS
          do
            gcloud compute disks delete --verbosity=info ${DISK} || continue
          done
          
          # Disks created by managed instance groups, and other jobs that start with "zebrad-"
          ZEBRAD_DISKS=$(gcloud compute disks list --sort-by=creationTimestamp  --filter="name~^zebrad- AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')

          for DISK in $ZEBRAD_DISKS
          do
            gcloud compute disks delete --verbosity=info ${DISK} || continue
          done

      # Deletes cache images older than $DELETE_AGE_DAYS days.
      #
      # Keeps the latest $KEEP_LATEST_IMAGE_COUNT images of each type:
      # - zebrad checkpoint cache
      # - zebrad tip cache
      # - lightwalletd + zebrad tip cache
      #
      # TODO: when we add testnet to the workflows, keep the latest $KEEP_LATEST_IMAGE_COUNT testnet images, 
      #       and the latest $KEEP_LATEST_IMAGE_COUNT mainnet images.
      - name: Delete old cache disks
        run: |
          DELETE_BEFORE_DATE=$(date --date="$DELETE_AGE_DAYS days ago" '+%Y%m%d')

          ZEBRAD_CHECKPOINT_IMAGES=$(gcloud compute images list --sort-by=~creationTimestamp --filter="name~^zebrad-cache-.*net-checkpoint AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')
          KEPT_IMAGES=0
          for IMAGE in $ZEBRAD_CHECKPOINT_IMAGES
          do
            if [[ "$KEPT_IMAGES" -lt "$KEEP_LATEST_IMAGE_COUNT" ]];
            then              
              KEPT_IMAGES=$((KEPT_IMAGES+1))
              echo "Keeping image $KEPT_IMAGES named $IMAGE"
              continue
            fi
            
            gcloud compute images delete ${IMAGE} || continue
          done

          ZEBRAD_TIP_IMAGES=$(gcloud compute images list --sort-by=~creationTimestamp --filter="name~^zebrad-cache-.*net-tip AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')
          KEPT_IMAGES=0
          for IMAGE in $ZEBRAD_TIP_IMAGES
          do
            if [[ "$KEPT_IMAGES" -lt "$KEEP_LATEST_IMAGE_COUNT" ]];
            then              
              KEPT_IMAGES=$((KEPT_IMAGES+1))
              echo "Keeping image $KEPT_IMAGES named $IMAGE"
              continue
            fi
            
            gcloud compute images delete ${IMAGE} || continue
          done
          
          LWD_TIP_IMAGES=$(gcloud compute images list --sort-by=~creationTimestamp --filter="name~^lwd-cache-.*net-tip AND creationTimestamp < $DELETE_BEFORE_DATE" --format='value(NAME)')
          KEPT_IMAGES=0
          for IMAGE in $LWD_TIP_IMAGES
          do
            if [[ "$KEPT_IMAGES" -lt "$KEEP_LATEST_IMAGE_COUNT" ]];
            then              
              KEPT_IMAGES=$((KEPT_IMAGES+1))
              echo "Keeping image $KEPT_IMAGES named $IMAGE"
              continue
            fi
            
            gcloud compute images delete ${IMAGE} || continue
          done