Parameters to use for callback to InvokeRESTAPI Azure Pipeline task

Question

Following the provided documentation for the Azure Pipeline InvokeRESTAPI task, I am trying to use the callback feature. The waitForCompletion argument must be true, and the callback triggered as follows.

To signal completion, the external service should POST completion data to the following pipelines REST endpoint.

{planUri}/{projectId}/_apis/distributedtask/hubs/{hubName}/plans/{planId}/events?api-version=2.0-preview.1

**Request Body**
{ "name": "TaskCompleted", "taskId": "taskInstanceId", "jobId": "jobId", "result": "succeeded" }

My problem is that I was unable to find more information about the parameters to use in the endpoint above.

• Is {planUri}/{projectId}/ the same as https://dev.azure.com/{organization}/{project}/?
• How can I find hubName and planId?
• I suppose that taskId and jobId are related to the Azure Pipeline that triggers the initial HTTP call, but how can one obtain them? I cannot seem to find them on the predefined variables list.

This information does not seem to be available in the distributedtask API documentation.