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Additional configurations

There are some additional, possibly useful, customization options for workflows.

Exiting with errors​

Invalid API requests or unexpected webhook payloads cause a failing response that can be used to fail the GitHub Actions step with the errors option.

The errors option defaults to false so failed requests do not cause the step to fail. This result can still be gathered from the ok output.

- name: Attempt to call an unknown method
  uses: slackapi/slack-github-action@v2.0.0
  with:
    errors: true
    method: chat.reverse
    token: ${{ secrets.SLACK_BOT_TOKEN }}
    payload: |
      text: "palindrome"

Invalid inputs to the GitHub Action, such as not including a payload, will always cause the GitHub step to fail.

Flattening nested payloads​

Variables and data provided in the payload might contain nested fields that need to be flattened before being sent with a webhook trigger to match the expected input format of Workflow Builder.

The payload-delimiter option will flatten the input payload using the provided delimiter and will also make values stringified:

- name: Flatten the default GitHub payload
  uses: slackapi/slack-github-action@v2.0.0
  with:
    payload-delimiter: "_"
    webhook: ${{ secrets.SLACK_WEBHOOK_URL }}
    webhook-type: webhook-trigger

Reference to the flattening implementation is available for exploration from within the flat package.

Parsing templated variables​

Additional variables provided in the Github event context and event payload can be used to replace templated variables in the input payload with the payload-templated option:

- name: Send custom JSON data to Slack workflow
  uses: slackapi/slack-github-action@v2.0.0
  with:
    payload-file-path: "./payload-slack-content.json"
    payload-templated: true
    webhook: ${{ secrets.SLACK_WEBHOOK_URL }}
    webhook-type: webhook-trigger

This replaces variables templated as ${{ github.payload.repository.html_url }} with the values found in the GitHub Action event payload.

Proxying HTTPS requests​

If you need to use a proxy to connect to Slack, you can use the proxy option. In this example we use the technique that calls a Slack API method, but configuring a proxy is the same for all techniques:

- name: Post to a Slack channel via a proxy
  uses: slackapi/slack-github-action@v2.0.0
  with:
    method: chat.postMessage
    proxy: "http://proxy.example.org:8080" # Change this to a custom value
    token: ${{ secrets.SLACK_BOT_TOKEN }}
    payload: |
      channel: ${{ secrets.SLACK_CHANNEL_ID }}
      text: "This message was sent through a proxy"

The proxy option can also be provided with the HTTPS_PROXY or https_proxy environment variable from within the GitHub Actions step.

Retrying failed requests​

Sometimes outgoing requests fail due to rate limits or similar HTTP responses and can be retried later.

The retries option can be configured to the needs of your workflow with one of these values:

  • 0: No retries, just hope that things go alright.
  • 5: Five retries in five minutes. Default.
  • 10: Ten retries in about thirty minutes.
  • RAPID: A burst of retries to keep things running fast.
- name: Attempt a burst of requests
  uses: slackapi/slack-github-action@v2.0.0
  with:
    method: chat.postMessage
    retries: RAPID
    token: ${{ secrets.SLACK_BOT_TOKEN }}
    payload: |
      channel: ${{ secrets.SLACK_CHANNEL_ID }}
      text: "status: all things are going good"

Behind the scenes, automatic retries are handled with the @slack/web-api package for Slack API methods, and axios-retry when sending with a webhook.

Sending to a custom API URL​

In certain circumstances, such as testing the sent payload, a custom API URL can be used to change where method requests are sent:

- name: Send to a custom API URL
  uses: slackapi/slack-github-action@v2.0.0
  with:
    api: http://localhost:8080
    method: chat.postMessage
    token: ${{ secrets.SLACK_BOT_TOKEN }}
    payload: |
      channel: ${{ secrets.SLACK_CHANNEL_ID }}
      text: "What's happening on localhost?"

The default value of api is https://slack.com/api/ for steps using method.