Workflow Webhook Action

A Github workflow action to call a remote webhook endpoint with a JSON or form-urlencoded payload, and support for BASIC authentication. A hash signature is passed with each request, derived from the payload and a configurable secret token. The hash signature is identical to that which a regular Github webhook would generate, and sent in a header field named X-Hub-Signature. Therefore any existing Github webhook signature validation will continue to work. For more information on how to valiate the signature, see https://docs.github.com/webhooks/securing/.

By default, the values of the following GitHub workflow environment variables are sent in the payload: GITHUB_REPOSITORY, GITHUB_REF, GITHUB_HEAD_REF, GITHUB_SHA, GITHUB_EVENT_NAME and GITHUB_WORKFLOW. For more information on what is contained in these variables, see https://help.github.com/en/actions/automating-your-workflow-with-github-actions/using-environment-variables.

These values map to the payload as follows:

{
    "event": "GITHUB_EVENT_NAME",
    "repository": "GITHUB_REPOSITORY",
    "commit": "GITHUB_SHA",
    "ref": "GITHUB_REF",
    "head": "GITHUB_HEAD_REF",
    "workflow": "GITHUB_WORKFLOW"
}

If you are interested in receiving more comprehensive data about the GitHub event than just the above fields, then the action can be configured to send the whole JSON payload of the GitHub event, as per the GITHUB_EVENT_PATH variable in the environment variable documentation referenced above. The official documentation and reference for the payload itself can be found here: https://developer.github.com/webhooks/event-payloads/, and the details on how to configure it, is further down in the Usage section of this README.

Additional (custom) data can also be added/merged to the payload (see further down).

Usage

The following are example snippets for a Github yaml workflow configuration.

Send the JSON (default) payload to a webhook:

    - name: Invoke deployment hook
      uses: distributhor/workflow-webhook@v3
      with:
        webhook_url: ${{ secrets.WEBHOOK_URL }}
        webhook_secret: ${{ secrets.WEBHOOK_SECRET }}

Will deliver a payload with the following properties:

{
    "event": "push",
    "repository": "owner/project",
    "commit": "a636b6f0861bbee98039bf3df66ee13d8fbc9c74",
    "ref": "refs/heads/master",
    "head": "",
    "workflow": "Build and deploy",
    "requestID": "74b1912d19cfe780f1fada4b525777fd"
}

requestID contains a randomly generated identifier for each request.

Add additional data to the payload:

    - name: Invoke deployment hook
      uses: distributhor/workflow-webhook@v3
      with:
        webhook_url: ${{ secrets.WEBHOOK_URL }}
        webhook_secret: ${{ secrets.WEBHOOK_SECRET }}
        data: '{ "weapon": "hammer", "drink" : "beer" }'

The additional information will become available on a data property, and now look like:

{
    "event": "push",
    "repository": "owner/project",
    "commit": "a636b6f0861bbee98039bf3df66ee13d8fbc9c74",
    "ref": "refs/heads/master",
    "head": "",
    "workflow": "Build and deploy",
    "data": {
        "weapon": "hammer",
        "drink": "beer"
    },
    "requestID": "74b1912d19cfe780f1fada4b525777fd"
}

Send a form-urlencoded payload instead:

    - name: Invoke deployment hook
      uses: distributhor/workflow-webhook@v3
      with:
        webhook_type: 'form-urlencoded'
        webhook_url: ${{ secrets.WEBHOOK_URL }}
        webhook_secret: ${{ secrets.WEBHOOK_SECRET }}
        data: 'weapon=hammer&drink=beer'

Will set the Content-Type header to application/x-www-form-urlencoded and deliver:

"event=push&repository=owner/project&commit=a636b6f0....&weapon=hammer&drink=beer"

Finally, if you prefer to receive the whole original GitHub payload as JSON (as opposed to the default JSON snippet above), then configure the webhook with a webhook_type of json-extended:

    - name: Invoke deployment hook
      uses: distributhor/workflow-webhook@v3
      with:
        webhook_type: 'json-extended'
        webhook_url: ${{ secrets.WEBHOOK_URL }}
        webhook_secret: ${{ secrets.WEBHOOK_SECRET }}
        data: '{ "weapon": "hammer", "drink" : "beer" }'

You can still add custom JSON data, which will be available on a data property, included on the GitHub payload. Importantly, the sending of the whole GitHub payload is only supported as JSON, and not currently available as urlencoded form parameters.

Arguments

  webhook_url: "https://your.webhook"

Required. The HTTP URI of the webhook endpoint to invoke. The endpoint must accept an HTTP POST request.

  webhook_secret: "Y0uR5ecr3t"

Optional. The secret with which to generate the signature hash. If no secret is configured, then the URL itself will be used as the value with which to generate the signature hash. This is useful for use-cases where the webhook URL might be an obscure, random or temporary link. In general it is advisable to use a webhook secret.

  webhook_auth_type: "bearer"

The type of authentication to use when invoking the webhook URL. Valid values are basic, bearer and header. Defaults to basic if not specified. In addition, if no value is set for webhook_auth, then it is assumed that no authentication is required, and this value, even if configured, will have no effect. It only takes effect when used in conjunction with webhook_auth. The expectations for how each option behaves, is explained in the webhook_auth section below.

  webhook_auth: "username:password"
  webhook_auth: "Token:ABC"
  webhook_auth: "ABC"

The credentials to be used for authentication of the the endpoint. If not configured, authentication is assumed not to be required.

If the webhook_auth_type is set to basic, then this value is expected to be a username:password string, used for BASIC authentication against the endpoint. It must follow this format, as specified in the curl man pages, since it is passed verbatim to the curl -u option.

If the webhook_auth_type is set to bearer, then this value is expected to be an access token. It will set a header named Authorization with a value of Bearer ${webhook_auth}.

If the webhook_auth_type is set to header, then the expecation is to receive a string similar in format to basic, except that the delimiter (a colon) will delimit a header name and header value. For example a value of Token:ABC will set a header named Token with a value of ABC. If no colon is present (no delimiter specified) then it will default to setting a header named Authorization of which the value will be whatever was configured for ${webhook_auth}, ie (no 'bearer') prefix. As an example, when configured with a value of ABC, a header named Authorization will be set to the value ABC.

  webhook_type: "json | form-urlencoded | json-extended"

The default endpoint type is JSON. The argument is only required if you wish to send urlencoded form data. Otherwise it's optional.

  verbose: true

To enable verbose output in curl set the argument verbose to true. The default value is false. See also: curl docs on option -v.

⚠️ Warning: This might lead to domain and IP leaking, as well as other security issues as the logs are public. See also #21 and #22.

  silent: true

To hide the output from curl set the argument silent to true. The default value is false.

  timeout: 30

To set a maximum time, in seconds, by which to establish an initial connection to the server. Once a connection has been established, the option is not used in any further way with regards to the duration of connection.

  max_time: 30

To set a maximum time, in seconds, by which the server needs to respond to the request. This also includes the time needed for the server to respond. May be used in combination with timeout.

  curl_opts: '--speed-limit 5000'
  curl_opts: '-H "X-Beverage: Beer"'

You can use curl_opts to pass in arbitrary options to the curl request. NOTE: this is an experimental feature and not guaranteed to work for all options. The string configured here will be passed in verbatim to curl, and it is quite easy to break things when using it. For simple curl options it should work, but for others it may not suffice. Also, take care with escaping characters in YAML.

  verify_ssl: false

To disable verification of SSL-certificates in curl set the argument verify_ssl to false. The default value is true. See also: curl docs on option -k.

  event_name: 'NAME'

Optional. A custom event name sent to the webhook endpoint

  data: "Additional JSON or URL encoded data"

Additional data to include in the payload. It is optional. This data will attempted to be merged 'as-is' with the existing payload, and is expected to already be sanitized and valid.

In the case of JSON, the custom data will be available on a property named data, and it will be run through a JSON validator. Invalid JSON will cause the action to break and exit. For example, using single quotes for JSON properties and values instead of double quotes, will show the following (somewhat confusing) message in your workflow output: Invalid numeric literal. Such messages are the direct output from the validation library https://stedolan.github.io/jq/. The supplied JSON must pass the validation run through jq.

Output

  response-body: 'The body of the webook response'

License

The MIT License (MIT). Please see License File for more information.