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.