Issue with grpc based exporters

[shivchelwa]

Hi,

I just started exploring manual instrumentation for my java application. When I tried to create a Tracer using below code, it fails as one of the grpc dependency is not found:

	SpanExporter spanExporter =  OtlpGrpcSpanExporter.builder().readProperties(properties).build();
    	SpanProcessor spanProcessor = BatchSpanProcessor.builder(spanExporter).build();
    	OpenTelemetrySdk.getGlobalTracerManagement().addSpanProcessor(spanProcessor);
        Tracer tracer = GlobalOpenTelemetry.get().getTracerProvider().get(MyClass.class.getPackageName());

The below exception is thrown:

Exception in thread "main" io.grpc.ManagedChannelProvider$ProviderNotFoundException: No functional channel service provider found. Try adding a dependency on the grpc-okhttp, grpc-netty, or grpc-netty-shaded artifact
at io.grpc.ManagedChannelProvider.provider(ManagedChannelProvider.java:65)
at io.grpc.ManagedChannelBuilder.forTarget(ManagedChannelBuilder.java:76)
at io.opentelemetry.exporter.jaeger.JaegerGrpcSpanExporterBuilder.build(JaegerGrpcSpanExporterBuilder.java:97)
...

Shouldn't grpc-okhttp, grpc-netty, or grpc-netty-shaded be one of the dependencies of the exporter(jaeger/otlp) project?

When I added this dependency explicitly and I get a different error most likely due to version compatibility. What version of grpc-okhttp should be added to resolve this issue?

[jkwatson]

Hi @shivchelwa . We specifically don't include one of the grpc channel providers because people may want to bring their own. Our examples use grpc-netty-shaded, so we know that works, at least with compatible versions.

[anuraaga]

@shivchelwa You will also need to use grpc-bom to manage grpc dependency conflicts, I've found there's generally a conflict unless adding the bom. If you use the bom, you should be able to use most versions of gRPC, I haven't dug into what our minimum would be but we don't use any special APIs so should be using pretty old stuff.