Migrate WebMvcTags to ServerRequestObservationConvention

[Laurens-W]

What's your motivation?

• Migrate WebMvcTags to ServerRequestObservationConvention #531

Anyone you would like to review specifically?

@timtebeek

Any additional context

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0-Migration-Guide#tag-providers-and-contributors-migration

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Did you explore whether to use low cardinality versus high cardinality? It seems more risky to assume low cardinality. Any thoughts on that subject?

[Laurens-W]

You're very much correct in saying choosing the wrong one can cause big issues in the ingestion of traces/metrics.
It'd be safer to apply high and require manual shifting of high/low than adding all as low and potentially causing issues!

I'll change it to high!

[timtebeek]

Added a test that fails just from having another method without any arguments, as that leads to class cast exception. Likely you'll need some form of limiting when to modify methods.

[timtebeek]

Great to see; I understand this one wasn't easy with the lack of public examples and the number of options that needed to be converted. Thanks for diving in! Let's see how it holds up in practice with the coming release.