Spring-boot: WebClient metrics support

[Delorien84]

It will be fine, to have metrics support for reactive org.springframework.web.reactive.function.client.WebClient. Currently there is support only for standard RestTemplate.

[jkschneider]

This depends on https://jira.spring.io/browse/SPR-16537. We currently don't have access to the parameterized URI to tag WebClient metrics with.

[bjartek]

The upstream issue is resolved now, Is this still blocked?

[jkschneider]

Nope, no longer blocked, but won't be picked up until Boot 2.1 I'm guessing.

[spencergibb]

It's in 5.0.5, so maybe 2.0.1?

[bjartek]

Yay!

[bjartek]

Was this in 2.0.2?

[snicoll]

@bjartek perhaps you’re using GitHub on your phone? If you don’t there is a milestone label on the right

[bjartek]

Yes this was on my phone. Sorry for the noice.

[michael-barker]

@bclozel Should this use the Reactor context to set the start time? I believe this could result in incorrect timings when the sequence is re-subscribed to. The specific scenario I'm thinking of is when using retries in Reactor. When the sequence is retried the duration will be the sum of the previous durations.

edit: Just added a commit for what I had in mind.

[bclozel]

Good catch @michael-barker !
This is now fixed with an additional test and a slightly different approach - using the Context is right, but doOnEach considers all signals, including onComplete (and we don't want to record metrics for that signal, in this case).

[michael-barker]

@bclozel Thanks!

[bjartek]

Thanks!

[wilkinsona]

Yes. Any WebClient created via the auto-configured WebClient.Builder should be instrumented when you have Actuator on the classpath. If that's not happening for you, please open a new issue with a minimal and complete sample that reproduces the problem.

[lubinson]

@wilkinsona Thanks, I just found this precondition. Previously I didn't use injected builder.