How to create a PubSub function that triggers after onWrite function

Question

I wan to create a pubsub function after a function.firestore.onWrite function is triggered, since this last one contains the cron to be specified in the pubsub.schedule(cron).onRun(=>{})

What will be the correct way to wait for the cron time to be created and "deploy" the pubsub function afterwards?, so is created once the cron is known.

Answer 1

This is not possible. Pubsub triggers do not allow for one-time future units of work to be scheduled at a specific moment in time. They only allows you to set a single schedule strictly adhered to at the time the function was published.

If you want to schedule a single unit of work in the future, you should use Cloud Tasks for that. It can be instructed to trigger an HTTP function at a future time you choose.

See also:

• How to schedule a firebase function, in limited times
• Cloud Functions for Firebase trigger on time?
• https://medium.com/firebase-developers/how-to-schedule-a-cloud-function-to-run-in-the-future-in-order-to-build-a-firestore-document-ttl-754f9bf3214a