feat(pubsub)!: set max ack extension period to 60 minutes

[diegomarquezp]

• Max ack extension period: we do not use a final variable storing the default value. We will instead build the library with a null value if not provided via beans, which will default to the core library's default value
• Max executor threads: we do not use a final variable storing the default value. The global executor bean, which relied on this default value, was removed and will now use the defaults from the core library.

[diegomarquezp]

Pubsub-bus failure is tracked in #3494

[meltsufin]

Instead of setting the default, can we just not set the property and automatically expose the default already configured in Pub/Sub client library?

[diegomarquezp]

Instead of setting the default, can we just not set the property and automatically expose the default already configured in Pub/Sub client library?

@meltsufin See https://github.com/googleapis/java-pubsub/blob/855653f1ae37c4c45600d2ef0c34e1804939e75a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Subscriber.java#L96-L105
The clients don't have these defaults publicly exposed. Should we propose this change in pubsub?

[meltsufin]

Why do you need access to the default property in Pub/Sub? You shouldn't need to use it directly. If you don't set it in DefaultSubscriberFactory.createSubscriber, the default will be used. The way to make sure it's not set, is to keep our value null. null -> default.

[diegomarquezp]

@meltsufin PTAL. We are now passing null values to build the subscriber. However, I found that the global executor bean became unnecessary since it defaults to the static values we are getting rid of. Not sure if there is a use case where a custom global executor with other values satisfies a special need?

[meltsufin]

There should be documentation updates corresponding to this too.

It looks like you included changes for DEFAULT_EXECUTOR_THREADS as well. Would it make sense to do it in a separate PR? Was it part of the original request?

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[diegomarquezp]

There should be documentation updates corresponding to this too.

It looks like you included changes for DEFAULT_EXECUTOR_THREADS as well. Would it make sense to do it in a separate PR? Was it part of the original request?

@meltsufin I double checked. There seems to not be a hard requirement on default threads (i.e. "the really important is max ack..."). I restricted this PR to only include the default max ack extension period updates and changed the docs accordingly.