WebClientExchangeTags does not handle non-standard status codes

[druppelt]

Currently when calling a service that returns non-standard status codes like 490 with the reactive webclient, the tagging for the metrics actuator will cause an exception.
I'm using version 2.1.5.RELEASE of spring-boot-starter-actuator and spring-boot-starter-webflux. If I find the time, I'll create a pull request. For which branch should I do that?

In case I don't find the time, here's what I found so far:
The issue is that HttpStatus is used instead of a raw int. org.springframework.boot.actuate.metrics.web.reactive.client.WebClientExchangeTags#status(ClientResponse) itself only needs the raw value, but calls response.statusCode() which calls HttpStatus.valueOf(getRawStatusCode()) which throws an IllegalArgumentException.
At this point the solution is easy, just use response.rawStatusCode().

But after that it fails in WebClientExchangeTags#outcome(ClientResponse), and here I'm not sure what an elegant solution would be. Either directly use the rawStatusCode and ditch the comfort of the HttpStatus enum, or add an option to create HttpStatus.UNKNOWN values with the rawStatusCode as constructor argument I guess. I prefer the latter solution, but it may have side effects, as the Enum is part of spring-web and thus used a lot (681 usages according to my IDE).

[snicoll]

@druppelt support of non-standard status code is a Spring Framework concern so I am wondering if we shouldn't move this one in spring-framework. Let's ask @poutsma first.

[rstoyanchev]

@druppelt can you clarify what the 490 is for this service? One option is to add more enum values if they are common enough.

[druppelt]

@rstoyanchev In my case 490 and 491 are API specific validation issues, so definitly not common.

From my understanding everything matching ^[1-5]\d{2}$ should be allowed as status code, though unknown codes may be mapped to x00, see https://greenbytes.de/tech/webdav/draft-ietf-httpbis-p2-semantics-25.html#rfc.section.6.p.2

For me it's totally fine if spring doesn't support non standard codes ootb, but there should be hooks available to add custom status codes. And something like metrics imho should try it's best to not cause exceptions.

[wilkinsona]

I don't think this should move to Framework as there are fixes to be made in Boot. We can work with the raw status from the ClientResponse and also use HttpStatus.Series when determining the outcome.