CodeNode.jsDelaying steps

Delaying a workflow

Use $.flow.delay to delay a step in a workflow.

These docs show you how to write Node.js code to handle delays. If you don’t need to write code, see our built-in delay actions.

Using $.flow.delay

$.flow.delay takes one argument: the number of milliseconds you’d like to pause your workflow until the next step executes. You can pause your workflow for as little as one millisecond, or as long as one year.

Note that delays happen at the end of the step where they’re called.

export default defineComponent({
  async run({ steps, $ }) {
    // Delay a workflow for 60 seconds (60,000 ms)
    $.flow.delay(60 * 1000)
 
    // Delay a workflow for 15 minutes
    $.flow.delay(15 * 60 * 1000)
 
    // Delay a workflow based on the value of incoming event data,
    // or default to 60 seconds if that variable is undefined
    $.flow.delay(steps.trigger.event?.body?.delayMs ?? 60 * 1000)
 
    // Delay a workflow a random amount of time
    $.flow.delay(Math.floor(Math.random() * 1000))
  }
});

Paused workflow state

When $.flow.delay is executed in a Node.js step, the workflow itself will enter a Paused state.

While the workflow is paused, it will not incur any credits towards compute time. You can also view all paused workflows in the Event History.

Credit usage

The length of time a workflow is delayed from $.flow.delay does not impact your credit usage. For example, delaying a 256 megabyte workflow for five minutes will not incur ten credits.

However, using $.flow.delay in a workflow will incur two credits.

One credit is used to initially start the workflow, then the second credit is used when the workflow resumes after its pause period has ended.

Exact credit usage depends on duration and memory configuration

If your workflow’s execution timeout limit is set to longer than default limit, it may incur more than two credits when using pd.flow.delay.

cancel_url and resume_url

Both the built-in Delay actions and $.flow.delay return a cancel_url and resume_url that lets you cancel or resume paused executions.

These URLs are specific to a single execution of your workflow. While the workflow is paused, you can load these in your browser or send an HTTP request to either:

  • Hitting the cancel_url will immediately cancel that execution
  • Hitting the resume_url will immediately resume that execution early

Since Pipedream pauses your workflow at the end of the step where you run call $.flow.delay, you can send these URLs to third party systems, via email, or anywhere else you’d like to control the execution of your workflow.

import axios from 'axios'
 
export default defineComponent({
  async run({ steps, $ }) {
    const { cancel_url, resume_url } = $.flow.delay(15 * 60 * 1000)
 
    // Send the URLs to a system you own
    await axios({
      method: "POST",
      url: `https://example.com`,
      data: { cancel_url, resume_url },
    });
 
    // Email yourself the URLs. Click on the links to cancel / resume
    $.send.email({
      subject: `Workflow execution ${steps.trigger.context.id}`,
      text: `Cancel your workflow here: ${cancel_url} . Resume early here: ${resume_url}`,
    });
  }
});
 
// Delay happens at the end of this step

When delays happen

Pipedream pauses your workflow at the end of the step where you call $.flow.delay. This lets you send the cancel_url and resume_url to third-party systems.

export default defineComponent({
  async run({ steps, $ }) {
    const { cancel_url, resume_url } = $.flow.delay(15 * 60 * 1000)
    // ... run any code you want here
  }
});
 
// Delay happens at the end of this step

Delays and HTTP responses

You cannot run $.respond after running $.flow.delay. Pipedream ends the original execution of the workflow when $.flow.delay is called and issues the following response to the client to indicate this state:

$.respond() not called for this invocation

If you need to set a delay on an HTTP request triggered workflow, consider using setTimeout instead.

setTimeout

Alternatively, you can use setTimeout instead of using $.flow.delay to delay individual workflow steps.

However, there are some drawbacks to using setTimeout instead of $.flow.delay. setTimeout will count towards your workflow’s compute time, for example:

export default defineComponent({
  async run({ steps, $ }) {
    // delay this step for 30 seconds
    const delay = 30000;
 
    return new Promise((resolve, reject) => {
      setTimeout(() => {
        resolve('timer ended')
      }, delay)
    })
  }
});
 

The Node.js step above will hold the workflow’s execution for this step for 30 seconds; however, 30 seconds will also contribute to your credit usage. Also consider that workflows have a hard limit of 750 seconds.