docs/.github/workflows/azure-preview-env-deploy-public.yml

name: Azure - Deploy Preview Environment (public)

# NOTE! This is specifically and only for github/docs.

# **What it does**: Build and deploy an Azure preview environment for this PR in github/docs
# **Why we have it**: It's our preview environment deploy mechanism, to docs public repo
# **Who does it impact**: All open source contributors.

# !!!
# ! This worflow has access to secrets, runs in the public repository, and clones untrusted user code.
# ! Modify with extreme caution
# !!!

on:
  pull_request_target:
    # Note that if someone makes a PR that touches `Dockerfile`
    # and `content/index.md`, this use of `paths` will still run.
    # It would run even if we appended `- '!Dockerfile'` to the list.
    # But if someone makes a PR that touches `Dockerfile` only, the
    # workflow will not run.
    paths:
      - 'content/**'
      - 'data/**'
      - 'assets/**'
  merge_group:

permissions:
  contents: read
  deployments: write

# This allows one deploy workflow to interrupt another
concurrency:
  group: 'preview-env @ ${{ github.head_ref || github.run_id }} for ${{ github.event.number || inputs.PR_NUMBER }}'
  cancel-in-progress: true

jobs:
  build-and-deploy-azure-preview-public:
    name: Build and deploy Azure preview environment (public)
    runs-on: ubuntu-latest
    if: github.repository == 'github/docs'
    timeout-minutes: 15
    environment:
      name: preview-env-${{ github.event.number }}
      # The environment variable is computer later in this job in
      # the "Get preview app info" step.
      # That script sets environment variables which is used by Actions
      # to link a PR to a list of environments later.
      url: ${{ env.APP_URL }}
    env:
      PR_NUMBER: ${{ github.event.number || github.run_id }}
      COMMIT_REF: ${{ github.event.pull_request.head.sha }}
      BRANCH_NAME: ${{ github.head_ref || github.ref_name }}
      NONPROD_REGISTRY_USERNAME: ghdocs

    steps:
      - name: 'Az CLI login'
        uses: azure/login@6c251865b4e6290e7b78be643ea2d005bc51f69a # pin @v2
        with:
          creds: ${{ secrets.NONPROD_AZURE_CREDENTIALS }}

      - name: 'Docker login'
        uses: azure/docker-login@15c4aadf093404726ab2ff205b2cdd33fa6d054c
        with:
          login-server: ${{ secrets.NONPROD_REGISTRY_SERVER }}
          username: ${{ env.NONPROD_REGISTRY_USERNAME }}
          password: ${{ secrets.NONPROD_REGISTRY_PASSWORD }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@d70bba72b1f3fd22344832f00baa16ece964efeb

      - name: Check out main branch
        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
          ref: 'main'
          persist-credentials: 'false'

      - name: Get preview app info
        env:
          APP_NAME_SEED: ${{ secrets.PREVIEW_ENV_NAME_SEED }}
        run: src/workflows/get-preview-app-info.sh

      - name: 'Set env vars'
        run: |
          # Image tag is unique to each workflow run so that it always triggers a new deployment
          echo "DOCKER_IMAGE=${{ secrets.NONPROD_REGISTRY_SERVER }}/${IMAGE_REPO}:${{ env.COMMIT_REF }}-${{ github.run_number }}-${{ github.run_attempt }}" >> $GITHUB_ENV

      - name: Check out user code to temp directory
        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
          path: ./user-code
          ref: ${{ env.COMMIT_REF }}

      # Move acceptable user changes into our main branch checkout
      - name: Move acceptable user changes
        run: |
          # Make sure recursive path expansion is enabled
          shopt -s globstar
          rsync -rptovR ./user-code/content/./**/*.md ./content
          rsync -rptovR ./user-code/assets/./**/*.png ./assets
          rsync -rptovR ./user-code/data/./**/*.{yml,md} ./data

      - uses: ./.github/actions/warmup-remotejson-cache
        with:
          restore-only: true

      - uses: ./.github/actions/precompute-pageinfo
        with:
          restore-only: true

      # In addition to making the final image smaller, we also save time by not sending unnecessary files to the docker build context
      - name: 'Prune for preview env'
        run: src/workflows/prune-for-preview-env.sh

      - name: 'Build and push image'
        uses: docker/build-push-action@1a162644f9a7e87d8f4b053101d1d9a712edc18c
        with:
          context: .
          push: true
          target: preview
          tags: ${{ env.DOCKER_IMAGE }}
          # we only pull the `main` cache image
          cache-from: type=registry,ref=${{ secrets.NONPROD_REGISTRY_SERVER }}/${{ github.repository }}:main-preview
          # `main-docker-cache.yml` handles updating the remote cache so we don't pollute it with PR specific code
          cache-to: ''
          build-args: |
            BUILD_SHA=${{ env.COMMIT_REF }}

      # Succeed despite any non-zero exit code (e.g. if there is no deployment to cancel)
      - name: 'Cancel any existing deployments for this PR'
        run: |
          az deployment group cancel --name ${{ env.DEPLOYMENT_NAME }} -g ${{ secrets.PREVIEW_ENV_RESOURCE_GROUP }} || true

      # Deploy ARM template is idempotent
      # Note: once the resources exist the image tag must change for a new deployment to occur (the image tag includes workflow run number, run attempt, as well as sha)
      - name: Run ARM deploy
        uses: azure/arm-deploy@a1361c2c2cd398621955b16ca32e01c65ea340f5
        with:
          scope: resourcegroup
          resourceGroupName: ${{ secrets.PREVIEW_ENV_RESOURCE_GROUP }}
          subscriptionId: ${{ secrets.NONPROD_SUBSCRIPTION_ID }}
          template: ./src/workflows/azure-preview-env-template.json
          deploymentName: ${{ env.DEPLOYMENT_NAME }}
          parameters: appName="${{ env.APP_NAME }}"
            containerImage="${{ env.DOCKER_IMAGE }}"
            dockerRegistryUrl="${{ secrets.NONPROD_REGISTRY_SERVER }}"
            dockerRegistryUsername="${{ env.NONPROD_REGISTRY_USERNAME }}"
            dockerRegistryPassword="${{ secrets.NONPROD_REGISTRY_PASSWORD }}"

      - name: Check that it can be reached
        # This introduces a necessary delay. Because the preview evironment
        # URL is announced to the pull request as soon as all the steps
        # finish, what sometimes happens is that a viewer of the PR clicks
        # that link too fast and are confronted with a broken page.
        # It's because there's a delay between the `azure/arm-deploy`
        # and when the server is actually started and can receive and
        # process requests.
        # By introducing a slight "delay" here we avoid announcing a
        # preview environment URL that isn't actually working just yet.
        # Note the use of `--fail`. It which means that if it actually
        # did connect but the error code was >=400, the command will fail.
        # The `--fail --retry N` combination means that a 4xx response
        # code will exit immediately but a 5xx will exhaust the retries.
        run: curl --fail --retry-connrefused --retry 5 -I ${{ env.APP_URL }}