问题
I need to run a cron job to perform a specific cloud function after a set interval only once but a bit unsure of how to do it. Is there any way to do this through the current google cloud platform?
回答1:
Update following our discussion below through comments:
If you want to "change a document in your Firestore database 2 hours after it has been created" you could do as follows:
- When creating the document in Firestore, save the date/time of creation, e.g. with
firebase.firestore.FieldValue.serverTimestamp() - Have an HTTP Cloud Function that you call regularly as explained below (every minutes? every 5 minutes?) and that, first, selects the documents that were created 2 hours ago (based on the saved timestamp) and then do the desired action on these docs.
If you want to trigger a Cloud Function through a cron job, note that you would normally do that through an HTTP Cloud Function, calling the Cloud Function URL via the cron job.
You can either use an external service like cron-job.org or you can use GCP's App Engine and Cloud Pub/Sub
See this video: https://www.youtube.com/watch?v=fEBPAMSk5_8
and this Blog post: https://firebase.googleblog.com/2017/03/how-to-schedule-cron-jobs-with-cloud.html
both from the Firebase team.
Finally note that recently GCP launched a new product, Cloud Scheduler, which can be used to call HTTP Cloud Functions.
来源：https://stackoverflow.com/questions/55548517/run-a-cron-job-only-once-after-a-set-time