How to remove all metrics in the defaultRegistry about client_java

[fstab]

You could create a new PrometheusRegistry registry = new PrometheusRegistry() for each test, and then register your metrics with that registry with .register(registry).

Does that work for you?

[michaelschuett-tomtom]

This does work for me I had to do a small refactor so that our metric class by default uses the default registry but then during tests we optionally pass PrometheusRegistry() when initializing the metrics class. This works out well now since all of our metrics are centralized through this class but it would get a little messy if any custom metrics are added outside of it.

The above solves my immediate issue although it would be nice if a clear()/reset() function existed on the prometheus registry for just this purpose so we don't have to expose this for testing. If the defaultRegistry in PrometheusRegistry was exposed for users to overwrite that would also work but maybe this causes other issues?

[holubec-petr]

Hi, I also ran into this problem. Our metrics can be enabled or disabled based on a user's request so I need to unregister all registered collectors on such a request. It was possible in simpleclient using the clear() method but it is missing in the new 1.x version.

I will provide PR with the clear() method in a few minutes.

[mimaison]

Having a method to clear the registry would be really helpful for tests. Sure we can inject a new PrometheusRegistry instance but that requires further refactoring to adapt code that used to use simpleclient.

[dhoard]

PrometheusRegistry clear() / reset() methods will cause test issues when using JUnit5 in parallel execution mode.