Slack webhook action

A GitHub Action which uses Incoming WebHooks to send messages to slack channels.

Inputs

slack_web_hook_url

Required The URL from Slack for the Incoming WebHook.

slack_json

Required You can use the Slack Block Kit Builder to build your own message. Just put this JSON into this input. You can use {{placeholders}} for more information.

{{placeholders}}

For example use {{GITHUB_ACTOR}} inside yourslack_json input to show the username of the person who started the action.

You can use all this {{placeholders}}:

Placeholder	Renders to
CUSTOM_COMMIT_URL	https://github.com/${repositoryName}/commit/${commitSHA}
CUSTOM_AUTHOR_LINK	http://github.com/${authorName}
CUSTOM_AUTHOR_PICTURE	http://github.com/${authorName}.png?size=32
CUSTOM_SHORT_GITHUB_SHA	process.env.GITHUB_SHA.substring(0, 7)
CUSTOM_COMMIT_MSG	commitMessage
CUSTOM_COMMIT_MSGS	all commit msgs from a given push (joined by \n)
CUSTOM_ACTION_LINK	https://github.com/${repositoryName}/actions/runs/${runId}
CUSTOM_GITHUB_ACTOR_AS_SLACK	creates an @UserName in the Slack message. Needs the slack_mention_mapping_file input, otherwise it will return the GitHub username.
GITHUB_WORKFLOW	The name of the workflow.
GITHUB_RUN_ID	A unique number for each run within a repository. This number does not change if you re-run the workflow run.
GITHUB_RUN_NUMBER	A unique number for each run of a particular workflow in a repository. This number begins at 1 for the workflow's first run, and increments with each new run. This number does not change if you re-run the workflow run.
GITHUB_ACTION	The unique identifier (id) of the action.
GITHUB_ACTIONS	Always set to true when GitHub Actions is running the workflow. You can use this variable to differentiate when tests are being run locally or by GitHub Actions.
GITHUB_ACTOR	The name of the person or app that initiated the workflow. For example, octocat.
GITHUB_REPOSITORY	The owner and repository name. For example, octocat/Hello-World.
GITHUB_EVENT_NAME	The name of the webhook event that triggered the workflow.
GITHUB_WORKSPACE	The GitHub workspace directory path. The workspace directory contains a subdirectory with a copy of your repository if your workflow uses the actions/checkout action. If you don't use the actions/checkout action, the directory will be empty. For example, /home/runner/work/my-repo-name/my-repo-name.
GITHUB_SHA	The commit SHA that triggered the workflow. For example, ffac537e6cbbf934b08745a378932722df287a53.
GITHUB_REF	The branch or tag ref that triggered the workflow. For example, refs/heads/feature-branch-1. If neither a branch or tag is available for the event type, the variable will not exist.
GITHUB_HEAD_REF	Only set for forked repositories. The branch of the head repository.
GITHUB_BASE_REF	Only set for forked repositories. The branch of the base repository.
GITHUB_SERVER_URL	Returns the URL of the GitHub server. For example: https://github.com.
GITHUB_API_URL	Returns the API URL. For example: https://api.github.com.
GITHUB_GRAPHQL_URL	Returns the GraphQL API URL. For example: https://api.github.com/graphql.

More information about the GitHub placeholders (which are environment variables).

slack_mention_mapping_file

Optional Path to a file which maps the GitHub Names or @mentions to Slack @mentions (e.g. slack_mention_mapping_file: ../.github/slack-name-mapping.json).

You need to go one dir up to be in your main directory

The file should look like:

{
  "john-smith": {
    "slackId": "1234465",
    "mentions": ["john", "johnSmith", "john-smith"]
  }
}

Where

• john-smith is the GitHub Username,
• slackId is the ID of the Slack-Account of this GitHub User (more here: https://api.slack.com/reference/surfaces/formatting#mentioning-users),
• mentions an Array of Strings which are used to replace e.g. @johnSmith with a real Slack @Mention, it's case insensitive.

Outputs

There are no outputs at the moment.

Example usage

Example .github/workflows/send-notification.yml shows how to send custom messages in slack.

Do not forget to add your secret and your custom Slack Block Kit JSON:

[...]
      - name: Slack notification
        uses: tiloio/slack-webhook-action@v1.0.1
        with:
          slack_web_hook_url: ${{ secrets.SLACK_WEBHOOK_URL }}
          slack_json: '{
                               "username": "{{GITHUB_ACTOR}}",
                               "text": "{{GITHUB_ACTOR}} made some notification",
                               "icon_url": "{{CUSTOM_AUTHOR_PICTURE}}",
                               "channel": "your_channel",
                               "blocks": [
                                   {
                                       "type": "section",
                                       "text": {
                                           "type": "mrkdwn",
                                           "text": "someone pushed something.\n_{{CUSTOM_COMMIT_MSG}}_"
                                       }
                                   },
                                   {
                                       "type": "context",
                                       "elements": [
                                           {
                                               "type": "mrkdwn",
                                               "text": ":speech_balloon: commit <{{CUSTOM_COMMIT_URL}}|{{CUSTOM_SHORT_GITHUB_SHA}}>"
                                           }
                                       ]
                                   }
                               ]
                           }'
[...]

Errors

Could not send notification: invalid_token

Your Incoming WebHook URL slack_web_hook_url is not valid.

Warnings

Could not get slack mention mapping!

Your slack_mention_mapping_file path is wrong or content is not JSON.

No commit message found in Event!

The GitHub Event has no commit which could be displayed. The content of the file should be:

The path of the file with the complete webhook event payload. For example, /github/workflow/event.json.

More information in the GitHub Actions Docs under environment variable GITHUB_EVENT_PATH.

License

Licensed under MIT.