Align Server Observation with OTel semantic convention

[vmeunier]

Hello,

There seems to be a divergence between https://opentelemetry.io/docs/specs/semconv/http/http-spans/#http-server-semantic-conventions and what Spring offers by default in ServerHttpObservationDocumentation.

For example :

• method should be http.request.method
• status should be http.response.status_code and should be an int and not a String
• uri should be http.route

I haven't listed all the differences, but these are the main ones I happened to notice.

I'd be happy to contribute if necessary.

[bclozel]

That is a breaking change so we could only consider this for 7.0. Also, this will cause upgrade concerns as 6.x apps and 7.x apps will not ship the same metadata and this is likely to break existing dashboards.

@shakuzen do you think we should reconsider our existing metadata for 7.0 (at least the stable conventions) or should this be handled by https://github.com/micrometer-metrics/micrometer-otel-conventions-experimental ?

[vmeunier]

Can we consider duplicating the keys to avoid making breaking changes, and mark the old ones as deprecated ?

[bclozel]

@vmeunier is there a way to mark attributes as deprecated and show that status in dashboards? That would be interesting.
Deprecating that in our own conventions would not tell much to most developers as they won't see it unless they extend those classes.

[vmeunier]

Not that I know of unfortunately, since attributes are only KeyValue pairs... And you're right, adding that info in your own code, no one will see it, so it's probably not the best idea.

Note : I just checked the ClientHttpObservationDocumentation class, and there are several keys that are not named correctly there as well.