set KV watcher ephemeral consumer name

[MauriceVanVeen]

Overview

A KV watcher uses an ephemeral consumer with a random name, to make it (optionally) more recognisable in the CLI and/or graphs in Grafana, allow for setting/overwriting the KV watcher name.

The behavior is documented in ADR-8.

[aricart]

@MauriceVanVeen this is a good suggestion

[ripienaar]

Do you have suggestions of what the names might be? How would you realistically tell 100 watchers apart in a meaningful way where the names are still random enough to avoid clashes?

[MauriceVanVeen]

@ripienaar, would say the random names could stay as-is (so no need to change the default), and adding the ability to explicitly set a name yourself if desired. Like the way you would manually name a durable consumer, but then setting such a name on the ephemeral consumer used by the watcher.

For example, then it would support the case where specific applications are using one/multiple watchers for a longer period of time. A recognisable name would help to identify the watchers, especially when using streams with durable consumers with explicit names combined with same/other apps also relying on KV watchers for state.

[ripienaar]

Would require some careful thinking for sure, how to detect clashes in consumer names cos that will big time mess up watcher functionality for example.

[MauriceVanVeen]

Yeah, either checking for clashes or using a custom name as a suffix Something like EGRF38JR_application_name_here.

[ripienaar]

Using description fields would be safer of course - but I understand its not quite as handy.

[derekcollison]

I have some thoughts on watchers and they may change (under the covers, not API or functionality wise) such that this is not as much an issue.

[jnmoyne]

From a monitoring point of view it would be cool if you can tell not just the application name that created the watcher but also what it's watching on.

[Jarema]

We can now leverage metadata to do that.