Support for metrics and tracing in Javalin web framework

[davidcurrie]

Is your feature request related to a problem? Please describe.
Support for Open Telemetry metrics and tracing in the Javalin web framework.

Describe the solution you'd like
To have automatic support for Open Telemetry metrics and tracing in Javalin.

Describe alternatives you've considered
No alternatives were considered.

Additional context
See discussion in javalin/javalin#523

[trask]

hi @davidcurrie! if you are interested in working on this, check out writing-instrumentation.md, writing-instrumentation-module.md, and using-instrumenter-api.md

[PhilKes]

@davidcurrie I was taking a look at this and even though there is no explicit support for javalin, metrics and spans are already created with the otel-javaagent. From what I can see the current version javalin-2.0.3 uses jetty-11.0, which is already supported by OpenTelemetry.
I set up an example javalin project with a simple REST Api and using the current opentelemetry-javaagent.jar, and both Spans for incoming HTTP Request as well as http_server metrics were created.

So is this already resolved or what is the expectation for new instrumentation?

[github-actions]

This has been automatically marked as stale because it has been marked as needing author feedback and has not had any activity for 7 days. It will be closed if no further activity occurs within 7 days of this comment.

[davidcurrie]

Sorry - somehow missed the question back in Feb. From what I remember, the issue with Javalin was that it's implemented as a single servlet hanging off /* so that's the path that was showing up on all the Jetty-based metrics. Unfortunately, we've been unable to continue with OpenTelemetry due to OSGi issues so I can't comment further and understand if this issue just gets closed out.

[cyanff]

From what I remember, the issue with Javalin was that it's implemented as a single servlet hanging off /* so that's the path that was showing up on all the Jetty-based metrics

Yeah, getting official otel support to get finer metrics would be great.