timeout-in-workflow

This error occurs when you try to use setTimeout(), setInterval(), or related timing functions directly inside a workflow function.

Error Message

Timeout functions like "setTimeout" and "setInterval" are not supported in workflow functions. Use the "sleep" function from "workflow" for time-based delays.

Workflow functions run in a sandboxed environment where timing functions like setTimeout() and setInterval() are not available. These functions rely on asynchronous scheduling that would break the deterministic replay guarantees that workflows depend on.

When a workflow suspends and later resumes, it replays from the event log. If timing functions were allowed, the replay would produce different results than the original execution.

Quick Fix

Use the sleep function from the workflow package for time-based delays. Unlike setTimeout(), sleep is tracked in the event log and replays correctly.

Before:

workflows/delayed.ts

export async function delayedWorkflow() {
  "use workflow";

  // Error - setTimeout is not available in workflow functions
  await new Promise(resolve => setTimeout(resolve, 5000)); 

  return 'done';
}

After:

workflows/delayed.ts

import { sleep } from 'workflow'; 

export async function delayedWorkflow() {
  "use workflow";

  // sleep is tracked in the event log and replays correctly
  await sleep('5s'); 

  return 'done';
}

Unavailable Functions

These timing functions cannot be used in workflow functions:

setTimeout()
setInterval()
setImmediate()
clearTimeout()
clearInterval()
clearImmediate()

Common Scenarios

Polling with Delays

If you need to poll an external service with delays between requests:

workflows/polling.ts

import { sleep } from 'workflow';

export async function pollingWorkflow() {
  "use workflow";

  let status = 'pending';

  while (status === 'pending') {
    status = await checkStatus(); // step function
    if (status === 'pending') {
      await sleep('10s'); 
    }
  }

  return status;
}

async function checkStatus() {
  "use step";
  const response = await fetch('https://api.example.com/status');
  const data = await response.json();
  return data.status;
}

Scheduled Delays

For workflows that need to wait for a specific duration:

workflows/reminder.ts

import { sleep } from 'workflow';

export async function reminderWorkflow(message: string) {
  "use workflow";

  // Wait 24 hours before sending reminder
  await sleep('24h'); 

  await sendReminder(message);

  return 'reminder sent';
}

async function sendReminder(message: string) {
  "use step";
  // Send reminder logic
}

The sleep function accepts duration strings like '5s', '10m', '1h', '24h', or milliseconds as a number. See the sleep API reference for more details.