deploy-existing-release.yml

name: Deploy Existing Release

on:
  workflow_dispatch:

# Ensure only one instance of either this or the publish workflow is running at a time
# This ensures that we don't put production into an inconsistent state
concurrency:
  group: 'prod-deployment'

jobs:
  deploy:
    runs-on: ubuntu-latest
    permissions:
      packages: write
      contents: write # Write is required to create/update releases
    steps:
      - name: Ensure pre-requisites for deployment are met
        id: validate_deployment
        uses: actions/github-script@v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const { owner, repo } = context.repo;
            /*
             * We load 20 releases here, it's unlikely that we will want to roll back
             * to a release older than that.
             */
            const PAGE_SIZE = 20;
            const releases = await github.rest.repos.listReleases({
              owner,
              repo,
              per_page: PAGE_SIZE,
            });
          
            /*
             * Pre-releases should not be considered for deployment here, the `publish-new-release` action 
             * should be used instead.
             */
            const availableReleases = releases.data.filter((release) => !release.prerelease);
            const targetRelease = availableReleases.find(
              (release) => release.tag_name === "${{github.ref_name}}"
            );
            if (!targetRelease) {
              throw new Error(`No recent release found for tag: ${{github.ref_name}}`);
            }
          
            console.log(
              `Found release ${targetRelease.id}, proceeding with deployment: ${targetRelease.html_url}`
            );
            return targetRelease.id;

      - name: Log in to the Container registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Deploy to Production
        # To emulate deployments here we are simply shifting the latest tag to the appropriate docker image.
        # In a real world scenario, you would replace this with your actual deployment steps.
        run: |
          docker pull ghcr.io/${{ github.repository }}:${{github.ref_name}}
          docker tag ghcr.io/${{ github.repository }}:${{github.ref_name}} ghcr.io/${{ github.repository }}:latest
          docker push ghcr.io/${{ github.repository }}:latest

      - name: Update latest pointer
        uses: actions/github-script@v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const { owner, repo } = context.repo;
            const previousLatestRelease = await github.rest.repos.getLatestRelease({
              owner,
              repo,
            });
            await github.rest.repos.updateRelease({
              owner,
              repo,
              release_id: previousLatestRelease.data.id,
              make_latest: false
            });
            await github.rest.repos.updateRelease({
              owner,
              repo,
              release_id: ${{ steps.validate_deployment.outputs.result }},
              make_latest: true
            });