action.yaml

name: Post Slack workflow conclusion notifications
description: Post a Slack message with the workflow conclusion via Slack incoming webhook.
inputs:
  # REQUIRED INPUTS
  slack-webhook-url:
    description: The Slack webhook URL.
    required: true
  status:
    description: The status of the workflow. One of 'success', 'failure', 'cancelled', or 'skipped'.
    required: true
  # OPTIONAL INPUTS
  payload:
    description: The Slack Block Kit JSON payload to send to Slack. If provided, this input will override all other inputs other than `slack-webhook-url`. https://app.slack.com/block-kit-builder
    required: false
    default: ''
  header:
    description: The notification header, as a plain text string. Defaults to the workflow name.
    required: false
  success-message:
    description: The message to display when the workflow is successful. Accepts markdown syntax.
    required: false
    default: ':large_green_circle: Workflow completed successfully :mario_luigi_dance:'
  failure-message:
    description: The message to display when the workflow is successful. Accepts markdown syntax.
    required: false
    default: ':red_circle: Workflow failed :sad-panda:'
  cancelled-message:
    description: The message to display when the workflow is cancelled. Accepts markdown syntax.
    required: false
    default: ':black_circle: Workflow cancelled'
  skipped-message:
    description: The message to display when the workflow is skipped. Accepts markdown syntax.
    required: false
    default: ':white_circle: Workflow skipped'
  tag:
    description: |
      Override the commit hash displayed in the notification by resolving this tag to its commit hash.
      If provided, this will be resolved to the actual commit hash.
      If the tag cannot be resolved, the notification will fallback to using the current commit hash.
    required: false
    default: ''

runs:
  using: composite
  steps:
    - name: Checkout repository
      if: ${{ inputs.tag != '' }}
      uses: actions/checkout@v4
      with:
        fetch-depth: 0  # Fetch full history to ensure all tags are available

    - name: Construct Slack variables
      id: slack-variables
      shell: bash
      run: |
        # Git Variables
        fallbackBranchName=$(echo "${{ github.ref }}" | cut -c12-)
        shortCommitHash=$(echo "${{ github.sha }}" | cut -c1-7)
        
        # Resolve tag to commit hash if provided, otherwise use default commit hash
        if [[ -n "${{ inputs.tag }}" ]]; then
          if lookupCommitHashForTag=$(git rev-parse "${{ inputs.tag }}" 2>&1); then
            shortCommitHash=$(echo "${lookupCommitHashForTag}" | cut -c1-7)
            echo "Resolved tag '${{ inputs.tag }}' to commit hash: ${lookupCommitHashForTag}"
          else
            echo "Error resolving tag '${{ inputs.tag }}': ${lookupCommitHashForTag}"
            echo "Falling back to current workflow commit hash: ${{ github.sha }}"
          fi
        fi

        # Determine status message
        if [[ "${{ inputs.status }}" == 'success' ]]; then
          statusMessage=$(echo "${{ inputs.success-message }}")
        elif [[ "${{ inputs.status }}" == 'failure' ]]; then
          statusMessage=$(echo "${{ inputs.failure-message }}")
        elif [[ "${{ inputs.status }}" == 'cancelled' ]]; then
          statusMessage=$(echo "${{ inputs.cancelled-message }}")
        elif [[ "${{ inputs.status }}" == 'skipped' ]]; then
          statusMessage=$(echo "${{ inputs.skipped-message }}")
        else
          echo "Invalid workflow status: ${{ inputs.status }}"
          exit 1
        fi

        # Output All Variables
        echo "fallback-branch-name=${fallbackBranchName}" >> $GITHUB_OUTPUT
        echo "short-commit-hash=${shortCommitHash}" >> $GITHUB_OUTPUT
        echo "status-message=${statusMessage}" >> $GITHUB_OUTPUT

        # Echo all variables for debugging
        echo "fallback-branch-name=${fallbackBranchName}"
        echo "short-commit-hash=${shortCommitHash}"
        echo "status-message=${statusMessage}"

    - name: Construct Slack payload
      id: slack-payload
      if: ${{ inputs.payload == '' }}
      shell: bash
      run: |
        PAYLOAD=$(cat << EOF
        {
          "blocks": [
            {
              "type": "header",
              "text": {
                "type": "plain_text",
                "text": "${{ inputs.header || github.workflow }}",
                "emoji": true
              }
            },
            {
              "type": "section",
              "text": {
                "type": "mrkdwn",
                "text": "${{ steps.slack-variables.outputs.status-message }}"
              }
            },
            {
              "type": "section",
              "fields": [
                {
                  "type": "mrkdwn",
                  "text": "*Repository:*\n<${{ github.server_url }}/${{ github.repository }}|${{ github.repository }}>"
                },
                {
                  "type": "mrkdwn",
                  "text": "*Branch:*\n<${{ github.server_url }}/${{ github.repository }}/tree/${{ github.head_ref || steps.slack-variables.outputs.fallback-branch-name }}|${{ github.head_ref || steps.slack-variables.outputs.fallback-branch-name }}>"
                },
                {
                  "type": "mrkdwn",
                  "text": "*Workflow Run:*\n<${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}|${{ github.run_number }}>"
                },
                {
                  "type": "mrkdwn",
                  "text": "*Commit:*\n<${{ github.server_url }}/${{ github.repository }}/commit/${{ github.sha }}|${{ steps.slack-variables.outputs.short-commit-hash }}>"
                }
              ]
            },
            {
              "type": "actions",
              "elements": [
                {
                  "type": "button",
                  "action_id": "view-workflow-run",
                  "style": "${{ inputs.status == 'failure' && 'danger' || 'primary' }}",
                  "url": "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}",
                  "text": {
                    "type": "plain_text",
                    "emoji": true,
                    "text": "${{ inputs.status == 'failure' && 'View failed run' || 'View workflow run' }}"
                  }
                }
              ]
            }
          ]
        }
        EOF
        )
        echo "payload<<EOF" >> $GITHUB_OUTPUT
        echo "$PAYLOAD" >> $GITHUB_OUTPUT
        echo "EOF" >> $GITHUB_OUTPUT

    - name: Send notification
      uses: slackapi/slack-github-action@fcfb566f8b0aab22203f066d80ca1d7e4b5d05b3 # v1.27.1
      env:
        SLACK_WEBHOOK_URL: ${{ inputs.slack-webhook-url }}
        SLACK_WEBHOOK_TYPE: 'INCOMING_WEBHOOK'
      with:
        payload: ${{ inputs.payload != '' && inputs.payload || steps.slack-payload.outputs.payload }}