wordpress/.github/workflows/slack-notifications.yml

##
# A reusable workflow for posting messages to the Making WordPress
# Core Slack Instance by submitting data to Slack webhook URLs
# received by Slack Workflows.
##
name: Slack Notifications

on:
  workflow_call:
    inputs:
      calling_status:
        description: 'The status of the calling workflow'
        type: string
        required: true
    secrets:
      SLACK_GHA_SUCCESS_WEBHOOK:
        description: 'The Slack webhook URL for a successful build.'
        required: true
      SLACK_GHA_CANCELLED_WEBHOOK:
        description: 'The Slack webhook URL for a cancelled build.'
        required: true
      SLACK_GHA_FIXED_WEBHOOK:
        description: 'The Slack webhook URL for a fixed build.'
        required: true
      SLACK_GHA_FAILURE_WEBHOOK:
        description: 'The Slack webhook URL for a failed build.'
        required: true

env:
  CURRENT_BRANCH: ${{ github.ref_name }}

jobs:
  # Gathers the details needed for Slack notifications.
  #
  # These details are passed as outputs to the subsequent, dependant jobs that
  # submit data to Slack webhook URLs configured to post messages.
  #
  # Performs the following steps:
  # - Retrieves the current workflow run.
  # - Determines the conclusion of the previous workflow run or run attempt.
  # - Sets the previous conclusion as an output.
  # - Prepares the commit message.
  # - Constructs and stores a message payload as an output.
  prepare:
    name: Prepare notifications
    runs-on: ubuntu-latest
    timeout-minutes: 5
    if: ${{ github.repository == 'WordPress/wordpress-develop' && github.event.workflow_run.event != 'pull_request' }}
    outputs:
      previous_conclusion: ${{ steps.previous-conclusion.outputs.previous_conclusion }}
      payload: ${{ steps.create-payload.outputs.payload }}

    steps:
      - name: Determine the status of the previous attempt
        id: previous-attempt-result
        uses: actions/github-script@98814c53be79b1d30f795b907e553d8679345975 # v6.4.0
        with:
          retries: 2
          retry-exempt-status-codes: 418
          script: |
            const workflow_run = await github.rest.actions.getWorkflowRun({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: ${{ github.run_id }},
            });

            // When a workflow has been restarted to fix a failure, check the previous run attempt.
            if ( workflow_run.data.run_attempt > 1 ) {
              const previous_run = await github.rest.actions.getWorkflowRunAttempt({
                owner: context.repo.owner,
                repo: context.repo.repo,
                run_id: ${{ github.run_id }},
                attempt_number: workflow_run.data.run_attempt - 1
              });

              return previous_run.data.conclusion;
            }

            // Otherwise, check the previous workflow run.
            const previous_runs = await github.rest.actions.listWorkflowRuns({
              owner: context.repo.owner,
              repo: context.repo.repo,
              workflow_id: workflow_run.data.workflow_id,
              branch: '${{ env.CURRENT_BRANCH }}',
              exclude_pull_requests: true,
            });

            // This is the first workflow run for this branch or tag.
            if ( previous_runs.data.workflow_runs.length < 2 ) {
              return 'none';
            }

            const expected_events = new Array( 'push', 'schedule', 'workflow_dispatch' );

            // Find the workflow run for the commit that immediately preceded this one.
            for ( let i = 0; i < previous_runs.data.workflow_runs.length; i++ ) {
              if ( previous_runs.data.workflow_runs[ i ].run_number == workflow_run.data.run_number ) {
                let next_index = i;
                do {
                  next_index++;

                  // Protects against a false notification when contributors use the trunk branch as the pull request head_ref.
                  if ( expected_events.indexOf( previous_runs.data.workflow_runs[ next_index ].event ) == -1 ) {
                    continue;
                  }

                  return previous_runs.data.workflow_runs[ next_index ].conclusion;
                } while ( next_index < previous_runs.data.workflow_runs.length );
              }
            }

            // Can't determine previous workflow conclusion.
            return 'unknown';

      - name: Store previous conclusion as an output
        id: previous-conclusion
        run: echo "previous_conclusion=${{ steps.previous-attempt-result.outputs.result }}" >> $GITHUB_OUTPUT

      - name: Get the commit message
        id: current-commit-message
        uses: actions/github-script@98814c53be79b1d30f795b907e553d8679345975 # v6.4.0
        if: ${{ github.event_name == 'workflow_dispatch' || github.event_name == 'schedule' }}
        with:
          retries: 2
          retry-exempt-status-codes: 418
          script: |
            const commit_details = await github.rest.repos.getCommit({
              owner: context.repo.owner,
              repo: context.repo.repo,
              ref: '${{ github.sha }}'
            });
            return commit_details.data.commit.message;

      - name: Prepare commit message.
        id: commit-message
        run: |
          COMMIT_MESSAGE=$(cat <<'EOF' | awk 'NR==1' | sed 's/`/\\`/g' | sed 's/\"/\\\\\\"/g' | sed 's/\$/\\$/g'
          ${{ ( github.event_name == 'workflow_dispatch' || github.event_name == 'schedule' ) && fromJson( steps.current-commit-message.outputs.result ) || github.event.head_commit.message }}
          EOF
          )
          echo "commit_message_escaped=${COMMIT_MESSAGE}" >> $GITHUB_OUTPUT

      - name: Construct payload and store as an output
        id: create-payload
        run: echo "payload={\"workflow_name\":\"${{ github.workflow }}\",\"ref_name\":\"${{ env.CURRENT_BRANCH }}\",\"run_url\":\"https://github.com/WordPress/wordpress-develop/actions/runs/${{ github.run_id }}/attempts/${{ github.run_attempt }}\",\"commit_message\":\"${{ steps.commit-message.outputs.commit_message_escaped }}\"}" >> $GITHUB_OUTPUT

  # Posts notifications when a workflow fails.
  failure:
    name: Failure notifications
    runs-on: ubuntu-latest
    timeout-minutes: 5
    needs: [ prepare ]
    if: ${{ inputs.calling_status == 'failure' || failure() }}

    steps:
      - name: Post failure notifications to Slack
        uses: slackapi/slack-github-action@007b2c3c751a190b6f0f040e47ed024deaa72844 # v1.23.0
        with:
          payload: ${{ needs.prepare.outputs.payload }}
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_GHA_FAILURE_WEBHOOK }}

  # Posts notifications the first time a workflow run succeeds after previously failing.
  fixed:
    name: Fixed notifications
    runs-on: ubuntu-latest
    timeout-minutes: 5
    needs: [ prepare ]
    if: ${{ contains( fromJson( '["failure", "cancelled", "none"]' ), needs.prepare.outputs.previous_conclusion ) && inputs.calling_status == 'success' && success() }}

    steps:
      - name: Post failure notifications to Slack
        uses: slackapi/slack-github-action@007b2c3c751a190b6f0f040e47ed024deaa72844 # v1.23.0
        with:
          payload: ${{ needs.prepare.outputs.payload }}
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_GHA_FIXED_WEBHOOK }}

  # Posts notifications when a workflow is successful.
  success:
    name: Success notifications
    runs-on: ubuntu-latest
    timeout-minutes: 5
    needs: [ prepare ]
    if: ${{ inputs.calling_status == 'success' && success() }}

    steps:
      - name: Post success notifications to Slack
        uses: slackapi/slack-github-action@007b2c3c751a190b6f0f040e47ed024deaa72844 # v1.23.0
        with:
          payload: ${{ needs.prepare.outputs.payload }}
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_GHA_SUCCESS_WEBHOOK }}

  # Posts notifications when a workflow is cancelled.
  cancelled:
    name: Cancelled notifications
    runs-on: ubuntu-latest
    timeout-minutes: 5
    needs: [ prepare ]
    if: ${{ inputs.calling_status == 'cancelled' || cancelled() }}

    steps:
      - name: Post cancelled notifications to Slack
        uses: slackapi/slack-github-action@007b2c3c751a190b6f0f040e47ed024deaa72844 # v1.23.0
        with:
          payload: ${{ needs.prepare.outputs.payload }}
        env:
          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_GHA_CANCELLED_WEBHOOK }}