Kamon context is not available to http4s logging middleware

[dangerousben]

The kamon context is not available to the http4s logging middleware. This can be seen by configuring logback to record the trace ID. There is a minimal reproduction at https://github.com/dangerousben/http4s-kamon-demo.

2021-01-20 08:32:39,752 [ioapp-compute-1] [2906519629fe1015] INFO Main$ In service
2021-01-20 08:32:39,945 [ioapp-compute-7] [undefined] INFO o.h.server.middleware.Logger HTTP/1.1 GET / Headers(Host: localhost:8080, User-Agent: HTTPie/1.0.3, Accept-Encoding: gzip, deflate, Accept: */*, Connection: keep-alive) body=""
2021-01-20 08:32:39,954 [ioapp-compute-6] [undefined] INFO o.h.server.middleware.Logger HTTP/1.1 200 OK Headers() body=""

The first log statement, within the service, includes the trace ID, but the following two from middleware.Logger do not.

[SimunKaracic]

Thanks for the demo! So, first thing you should try, is moving your main method somewhere else, to an object that doesn't extend anything. From there, call Kamon.init(), and then the run method on the object that extends IOApp!

That way, Kamon will really be the first thing that's loaded.

Try it out and let me know!

@dpsoft , do you have any ideas?

[dangerousben]

Separate Main class: https://github.com/dangerousben/http4s-kamon-demo/tree/feature/separate-main

Note that it actually calls the main method on App so that IOApp is initialised correctly, but Main is configured as the main class in sbt.

Same result though:

2021-01-20 14:58:08,442 [ioapp-compute-1] [ce8f481f3375185e] INFO App$ In service
2021-01-20 14:58:08,600 [ioapp-compute-7] [undefined] INFO o.h.server.middleware.Logger HTTP/1.1 GET / Headers(Host: localhost:8080, User-Agent: HTTPie/1.0.3, Accept-Encoding: gzip, deflate, Accept: */*, Connection: keep-alive) body=""
2021-01-20 14:58:08,609 [ioapp-compute-7] [undefined] INFO o.h.server.middleware.Logger HTTP/1.1 200 OK Headers() body=""