minitrace-opentelemetry doesn't work with opentelemetry_zipkin exporter

[dotansimha]

Seems like using opentelemetry_otlp works great (https://github.com/tikv/minitrace-rust/tree/master/minitrace-opentelemetry), but when an exporter from opentelemetry_zipkin (https://crates.io/crates/opentelemetry-zipkin) is in use, seems like the global collector expects a tokio runtime to be available, and fails with:

thread 'minitrace-global-collector' panicked at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/ops/function.rs:250:5:
there is no reactor running, must be called from the context of a Tokio 1.x runtime

This is how I configured the reporter and exporter:

let exporter = opentelemetry_zipkin::new_pipeline()
          .with_service_name(service_name)
          .with_collector_endpoint(endpoint)
          .init_exporter()?;

let reporter = OpenTelemetryReporter::new(exporter,  SpanKind::Server, resource, lib);

I assume it might be related to the fact that

[andylokandy]

Do you have a tokio runtime initialized when creating the zipkin reporter?

[andylokandy]

opentelemetry community is sort of messy at this moment... while opentelemetry_jaeger must be used in a environment without tokio, opentelemetry_zipkin requires the opposite.. But anyway I do have workaround: make a Reporter wrapper who ensure that a tokio runtimr exists and call inner reporter afterwards.

[dotansimha]

Do you have a tokio runtime initialized when creating the zipkin reporter?

I am using actix as web server, and it's a wrapper around tokio, so yeah I do have one.

opentelemetry community is sort of messy at this moment... while opentelemetry_jaeger must be used in a environment without tokio, opentelemetry_zipkin requires the opposite.. But anyway I do have workaround: make a Reporter wrapper who ensure that a tokio runtimr exists and call inner reporter afterwards.

I agree it's kinda it's in a mess, but the recent changes of providing the Runtime to each SpanProcessor kinda makes sense (also related: #179 (comment)).
I can create a processor that uses async runtime, or not.

I prefer the Reporter trait and it's simplicity, and it might be easier to implement a "native" minitrace exporter for Zipkin, instead of using the opentelemetry_rust one.