Enqueuing a Workflow Run (Fire and Forget)

This example assumes we have a workflow registered on a running worker.

Another method of triggering a workflow in Hatchet is to enqueue the workflow without waiting for it to complete, sometimes known as “fire and forget”. This pattern is useful for workflows that take a long time to complete or are not critical to the immediate operation of your application.

Some example use cases for fire-and-forget style workflows might be:

1. Sending a shipping confirmation email to a user once their order has shipped. This is a truly async task, in the sense that the user is not necessarily using your application when it happens, and the part of the application triggering the workflow does not need to know the result of the work, just that it has been enqueued (assuming that it will complete, of course).
2. Triggering a machine learning model training job that can take minutes, hours, or even days to complete. Similarly to above, it’s likely that no part of the application needs to wait on the result of this work, it just needs to “fire and forget” it - meaning that it needs to kick it off, and let it complete whenever it completes.

from src.workflows import my_workflow, MyWorkflowInputModel
 
ref = my_workflow.run_no_wait(MyWorkflowInputModel(foo="bar"))

ref = await my_workflow.aio_run_no_wait(input=MyWorkflowInputModel(foo="bar"))

import { simple } from './workflow';
// ...
  const run = await simple.runNoWait({
    Message: 'hello',
  });

  const runId = await run.getWorkflowRunId();
  // It may be helpful to store the run ID of the workflow
  // in a database or other persistent storage for later use
  console.log(runId);

Subscribing to results from an enqueued workflow

Often is is useful to subscribe to the results of a workflow at a later time. The run_no_wait method returns a WorkflowRunRef object which includes a listener for the result of the workflow.

result = ref.result()

result = await ref.aio_result()

// the return object of the enqueue method is a WorkflowRunRef which includes a listener for the result of the workflow
const result = await run.result();
console.log(result);

// if you need to subscribe to the result of the workflow at a later time, you can use the runRef method and the stored runId
const ref = hatchet.runRef<SimpleOutput>(runId);
const result2 = await ref.result();
console.log(result2);

Triggering Runs in the Hatchet Dashboard

In the Hatchet Dashboard, you can trigger and view runs for your workflows.

Navigate to “Workflow Runs” in the left sidebar and click “Trigger Run” at the top right.

You can specify run parameters such as Input, Additional Metadata, and the Scheduled Time.