Slack Messaging Action

A GitHub Action for sending (and updating) messages of any layout and formatting from GitHub Actions to Slack. Inspired by Slack Notify Build.

A Slack bot token is required to use this action, and the associated app must be granted permission to post in the channel, private group or DM you specify.

Usage

uses: wearerequired/slack-messaging-action@v1
with:
  bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
  channel: deployments
  payload: >-
    {
        "icon_emoji": ":rocket:",
        "username": "Deployer",
        "attachments": [
            {
                "author_name": "${{ github.event.sender.login }}",
                "author_link": "${{ github.event.sender.html_url }}",
                "author_icon": "${{ github.event.sender.avatar_url }}",
                "color": "good",
                "fallback": "Deployment finished.",
                "pretext": "Deployment finished.",
                "fields": [
                    {
                      "title": "Revision",
                      "value": "<https://github.com/${{ github.repository }}/commit/${{ github.sha }}|${{ github.sha }}@${{ github.ref }}>",
                      "short": true
                    }
                ],
                "footer": "<https://github.com/${{ github.repository }}|${{ github.repository }}>",
            }
        ]
    }

In payload you have to provide your own rich message layout which will be sent as is to Slack.

Updating an existing message

If you prefer to update a single message instead of posting multiple messages, you can pass a message_id to future steps.

Note: You must assign a step id to the first Slack notification step in order to reference it for future steps:

- name: Notify Slack about deployment start
  if: success()
  id: slack # IMPORTANT: Reference this step ID value in future Slack steps.
  uses: wearerequired/slack-messaging-action@v1
  with:
    bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
    channel: deployments
    payload: >-
      {
          "icon_emoji": ":rocket:",
          "username": "Deployer",
          "text": "Deployment started."
      }

- name: Deployment

- name: Notify Slack about deployment success
  if: success() # You can use the conditional checks to determine which notification to send.
  uses: wearerequired/slack-messaging-action@v1
  with:
    bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
    message_id: ${{ steps.slack.outputs.message_id }} # Updates existing message from the first step.
    channel: deployments
    payload: >-
      {
          "icon_emoji": ":rocket:",
          "username": "Deployer",
          "text": "Deployment finished."
      }

- name: Notify Slack about deployment fail
  if: failure() # You can use the conditional checks to determine which notification to send.
  uses: wearerequired/slack-messaging-action@v1
  with:
    bot_token: ${{ secrets.SLACK_BOT_TOKEN }}
    message_id: ${{ steps.slack.outputs.message_id }} # Updates existing message from the first step.
    channel: deployments
    payload: >-
      {
          "icon_emoji": ":boom:",
          "username": "Deployer",
          "text": "Deployment failed."
      }

Inputs

bot_token

A bot token associated with a Slack app. Required

Note: The following bot token scopes are required: chat:write, chat:write.customize, chat:write.public, channels:read, and groups:read.

channel

The name of the channel to post the message to. Required if no channel_id is provided.

Note: If your workspace has many channels, supplying only a channel may cause rate limiting issues with this GitHub Action. Consider supplying a channel_id instead.

channel_id

The ID of the channel to post the message to. Required if no channel is provided, or if you need to send to a DM.

payload

The JSON payload of a message to send. Required

Note: channel and ts are set to the values of the respective inputs.

message_id

The ID of a previous Slack message to update instead of posting a new message. Typically passed using the steps context:

message_id: ${{ steps.<your_first_slack_step_id>.outputs.message_id }}

Outputs

message_id

Returns the unique message ID, which is a timestamp which can be passed to future Slack API calls as ts.

License

The scripts and documentation in this project are released under the MIT license.