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Human-in-the-loop use case

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Start a new project using a human-in-the-loop (HITL) use case example.

Python SDK

Human-in-the-loop use case project example

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TypeScript SDK

Human-in-the-loop use case project example

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Problem​

You want to build a system that requires human input at certain stages of the process, such as manual review or approval.

How do you suspend a business process until a human completes a task, and then resume it once the task is done?

Solution​

Await a Durable Promise to block the process until the human completes their task, then resolve the Promise to resume execution.

Quick example​

// process x
function* foo(context: Context, workflowId: string): Generator<any, void, any> {
  // create a promise
  const blockingPromise = yield* context.promise();
  // expose the id to the outside world
  yield* context.run(sendEmail, blockingPromise.id);
  console.log(`blocked, waiting on human interaction`);
  // wait until the promise is resolved
  yield* blockingPromise;
  console.log(`unblocked, promise resolved`);
  return;
}

// process y
app.get("/unblock-workflow", async (req: Request, res: Response) => {
  // expose an endpoint to resolve the promise
  try {
    // ...
    // unblock a workflow by resolving a promise
    await resonate.promises.resolve(promiseId);
    // ...
  } catch (err: any) {
    // ...
  }
});