make edot sampler default instead of forcing it on

[anuraaga]

This updates to the proposal for sampler behavior for EDOT.

/cc @trentm

[jackshirazi]

Central config handling needs to output a warning when sampling rate is changed and the sampler isn't the dynamic handling one

[anuraaga]

Thanks @jackshirazi - since the SDK isn't exposed in a way for something like instanceof, I used a somewhat indirect way of recording it was initialized. Does it make sense?

[jackshirazi]

That's too fragile, any touch from future maintenance to the class would result in the wrong state.

We have ConfigLoggingAgentListener which is triggered after the agent is fully configured. You can test there, eg add

if (autoConfiguredOpenTelemetrySdk
                .getOpenTelemetrySdk()
                .getSdkTracerProvider()
                .getSampler() instanceof ...)
something = true

[anuraaga]

Ah good call, that's more clear. I went with checking in the existing ConfigLoggingAgentListener. Another idea is to have CentralConfig itself also be an AgentListener to keep it more composed but left it since it would be a bigger change.

[jackshirazi]

this should be private, with a public getter

[anuraaga]

Good call, fixed

[jackshirazi]

Thank you for this improvement!