Context propagation lost when using coroutines

[simplekjl]

Description

I've hit on a crucial and subtle point about tracing in a multi-threaded, multi-client environment.
When different auth-token requirements exist, we cannot use a single shared OkHttpClient; each client needs its own configuration.
The bigger issue, however, is that spans are not linking correctly due to how context is managed across different threads with Kotlin coroutines.
I have added the following:

runBlocking(ioDispatcher + Context.current().asContextElement()) {
     // tasks
}

Expected Behavior

The active span context should propagate correctly to child coroutines and OkHttp interceptors, so that spans are properly linked.

Actual Behavior

Context is lost when switching threads in runBlocking, causing spans to appear disconnected (no parent span).

[breedx-splk]

Thanks @simplekjl. Would you mind opening another separate issue about the multi-auth-token multi-threaded thing? I think it would be good to track that separately and for us to better understand this use case. Thanks!

As far as the coroutine context-switching goes, I don't think we have anything that does this automatically. Did you try passing the context manually? Would you be able to share a more complete but minimal example that demonstrates your problem?

It's interesting to think about eventually doing some build-time bytecode manipulation to make context tracking, especially for threads/coroutines, simpler for developers.

[LikeTheSalad]

Seems related to #239

[breedx-splk]

Yeah, we should decide which issue we want to keep.

[simplekjl]

Hi @breedx-splk @LikeTheSalad, I think it’s the same issue. I’ve tried both the automated approach and also passing the Otel context to my coroutines, but neither is working at the moment—the parent span doesn’t reflect some of the traces.

For more context: my application has two internal clients, one authorized and the other not. I need to communicate with both systems for different purposes during operations. I’ve noticed that only the calls made through one client go into the span in context. The other client’s traces are recorded, but they appear outside the span.

[marandaneto]

probably would need something similar to https://github.com/getsentry/sentry-java/blob/main/sentry-kotlin-extensions/src/main/java/io/sentry/kotlin/SentryContext.kt so you can copy-pass the context across coroutines