Emit schema url from instrumentations

[trask]

Is your feature request related to a problem? Please describe.

Currently none of the instrumentations emit schema url, which makes it harder for backends to detect which version of semantic conventions are being emitted (in particular relevant for old vs stable semconv like HTTP, and soon Database).

Describe the solution you'd like

Emit the appropriate schema url from each instrumentation

Describe alternatives you've considered

No response

Additional context

No response

[jack-berg]

If I'm understanding correctly, all instrumentations (stable or experimental) should be able to emit schema url (if applicable):

Unstable instrumentations provide no guarantees about the shape of the telemetry they produce and how that shape changes over time, from version to version. Span or metric names, attributes of any telemetry items may change without any restrictions. The produced telemetry MAY specify a Schema URL if the telemetry data conforms to a particular Schema.

[crossoverJie]

https://github.com/open-telemetry/opentelemetry-java/blob/main/sdk/common/src/main/java/io/opentelemetry/sdk/resources/Resource.java#L110-L113

 I noticed that this attribute already exists. Is it not meant for this purpose?

[trask]

@crossoverJie is this export from the Java agent? can you find where in the Java agent code we're setting it?

[crossoverJie]

@crossoverJie is this export from the Java agent? can you find where in the Java agent code we're setting it?

It may be the features introduced by these two PRs.

open-telemetry/opentelemetry-java#3319
#5752

[trask]

are you seeing schema url only on resource, or are you also seeing schema url populated on instrumentation scope?