name: 'Update build tools image tag'

# This workflow it used to update tag of build tools in ECR.
# The most common use case is adding/moving `pinned` tag to `${GITHUB_RUN_IT}` image.

on:
  workflow_dispatch:
    inputs:
      from-tag:
        description: 'Source tag'
        required: true
        type: string
      to-tag:
        description: 'Destination tag'
        required: true
        type: string
        default: 'pinned'

defaults:
  run:
    shell: bash -euo pipefail {0}

env:
  AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_DEV }}
  AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_KEY_DEV }}

permissions: {}

jobs:
  tag-image:
    runs-on: [ self-hosted, gen3, small ]
    container: golang:1.19-bullseye

    env:
      IMAGE: 369495373322.dkr.ecr.eu-central-1.amazonaws.com/build-tools
      FROM_TAG: ${{ inputs.from-tag }}
      TO_TAG: ${{ inputs.to-tag }}
    outputs:
      next-digest-buildtools: ${{ steps.next-digest.outputs.next-digest-buildtools }}
      prev-digest-buildtools: ${{ steps.prev-digest.outputs.prev-digest-buildtools }}

    steps:
      - name: Install Crane & ECR helper
        run: |
          go install github.com/google/go-containerregistry/cmd/crane@a54d64203cffcbf94146e04069aae4a97f228ee2 # v0.16.1
          go install github.com/awslabs/amazon-ecr-credential-helper/ecr-login/cli/docker-credential-ecr-login@adf1bafd791ae7d4ff098108b1e91f36a4da5404 # v0.7.1

      - name: Configure ECR login
        run: |
          mkdir /github/home/.docker/
          echo "{\"credsStore\":\"ecr-login\"}" > /github/home/.docker/config.json

      - name: Get source image digest
        id: next-digest
        run: |
          NEXT_DIGEST=$(crane digest ${IMAGE}:${FROM_TAG} || true)
          if [ -z "${NEXT_DIGEST}" ]; then
            echo >&2 "Image ${IMAGE}:${FROM_TAG} does not exist"
            exit 1
          fi

          echo "Current ${IMAGE}@${FROM_TAG} image is ${IMAGE}@${NEXT_DIGEST}"
          echo "next-digest-buildtools=$NEXT_DIGEST" >> $GITHUB_OUTPUT

      - name: Get destination image digest (if already exists)
        id: prev-digest
        run: |
          PREV_DIGEST=$(crane digest ${IMAGE}:${TO_TAG} || true)
          if [ -z "${PREV_DIGEST}" ]; then
            echo >&2 "Image ${IMAGE}:${TO_TAG} does not exist (it's ok)"
          else
            echo >&2 "Current ${IMAGE}@${TO_TAG} image is ${IMAGE}@${PREV_DIGEST}"

            echo "prev-digest-buildtools=$PREV_DIGEST" >> $GITHUB_OUTPUT
          fi

      - name: Tag image
        run: |
          crane tag "${IMAGE}:${FROM_TAG}" "${TO_TAG}"

  rollback-tag-image:
    needs:  tag-image
    if: ${{ !success() }}

    runs-on: [ self-hosted, gen3, small ]
    container: golang:1.19-bullseye

    env:
      IMAGE: 369495373322.dkr.ecr.eu-central-1.amazonaws.com/build-tools
      FROM_TAG: ${{ inputs.from-tag }}
      TO_TAG: ${{ inputs.to-tag }}

    steps:
      - name: Install Crane & ECR helper
        run: |
          go install github.com/google/go-containerregistry/cmd/crane@a54d64203cffcbf94146e04069aae4a97f228ee2 # v0.16.1
          go install github.com/awslabs/amazon-ecr-credential-helper/ecr-login/cli/docker-credential-ecr-login@adf1bafd791ae7d4ff098108b1e91f36a4da5404 # v0.7.1

      - name: Configure ECR login
        run: |
          mkdir /github/home/.docker/
          echo "{\"credsStore\":\"ecr-login\"}" > /github/home/.docker/config.json

      - name: Restore previous tag if needed
        run: |
          NEXT_DIGEST="${{ needs.tag-image.outputs.next-digest-buildtools }}"
          PREV_DIGEST="${{ needs.tag-image.outputs.prev-digest-buildtools }}"

          if [ -z "${NEXT_DIGEST}" ]; then
            echo >&2 "Image ${IMAGE}:${FROM_TAG} does not exist, nothing to rollback"
            exit 0
          fi

          if [ -z "${PREV_DIGEST}" ]; then
            # I guess we should delete the tag here/untag the image, but crane does not support it
            # - https://github.com/google/go-containerregistry/issues/999

            echo >&2 "Image ${IMAGE}:${TO_TAG} did not exist, but it was created by the job, no need to rollback"

            exit 0
          fi

          CURRENT_DIGEST=$(crane digest "${IMAGE}:${TO_TAG}")
          if [ "${CURRENT_DIGEST}" == "${NEXT_DIGEST}" ]; then
            crane tag "${IMAGE}@${PREV_DIGEST}" "${TO_TAG}"

            echo >&2 "Successfully restored ${TO_TAG} tag from ${IMAGE}@${CURRENT_DIGEST} to ${IMAGE}@${PREV_DIGEST}"
          else
            echo >&2 "Image ${IMAGE}:${TO_TAG}@${CURRENT_DIGEST} is not required to be restored"
          fi