Google Cloud Functions to only Ack Pub/Sub on success (Problem resolved by GCP)
google-cloud-functions, google-cloud-pubsub
Solution
This is a problem because Functions ACKing a message on invoke, even if they crash, prevents the use of the new "dead-letter" feature.
Also, it goes against the docs. see note after this code sample: https://cloud.google.com/functions/docs/calling/pubsub#sample_code
Problem
An early version of Google Cloud Functions had a limitation with regards to retries when errors occurred. They have since provided enhancements that resolve this issue. We are using a cloud function triggered by Pub/Sub to ensure delivery of an e-mail. Sometimes the e-mail service takes a long time to respond and our cloud function terminates before we get an error back. Since the message has already been acknowledged our e-mail gets lost. The cloud function appears to be sending an ACK the Pub/Sub message automatically when we are called. Is there a way to delay the ACK until the successful completion of our code? Alternatively is there a way to catch timeouts and requeue the message for delivery? Something else we could try?