How to ensure distributed tracing works with gRPC and OpenTelemetry in a microservices architecture?
I'm trying to implement I'm trying to implement I'm reviewing some code and I'm building a microservices architecture using gRPC for communication and I want to implement distributed tracing using OpenTelemetry. However, I'm running into issues where the trace data seems inconsistent, and I'm not seeing the spans associated with the correct requests in Jaeger. Specifically, when I make a call from Service A to Service B, I expect the trace context to propagate, but I'm getting separate root spans instead. Here's a simplified version of my code snippets: **Service A (gRPC Client):** ```go import ( "context" "google.golang.org/grpc" otel "go.opentelemetry.io/otel" "go.opentelemetry.io/otel/trace" ) func callServiceB() { ctx, span := otel.Tracer("service-a").Start(context.Background(), "callServiceB") defer span.End() conn, err := grpc.Dial("service-b:50051", grpc.WithInsecure()) if err != nil { log.Fatalf("did not connect: %v", err) } defer conn.Close() client := NewServiceBClient(conn) _, err = client.SomeMethod(ctx, &SomeRequest{}) if err != nil { span.RecordError(err) } } ``` **Service B (gRPC Server):** ```go import ( "context" "google.golang.org/grpc" otel "go.opentelemetry.io/otel" ) func (s *server) SomeMethod(ctx context.Context, req *SomeRequest) (*SomeResponse, error) { ctx, span := otel.Tracer("service-b").Start(ctx, "SomeMethod") defer span.End() // Processing logic return &SomeResponse{}, nil } ``` Despite using the `context` that has the trace data from Service A, it seems like Service B is not picking up the existing trace context properly. I've checked that both services are using the same OpenTelemetry Collector and that I have the necessary middleware for gRPC setup correctly. I also verified that the OpenTelemetry Go SDK is up to date (v1.0.0). When I look at Jaeger, I see two separate traces instead of a single trace with spans for both services. I've tried adding `grpc_middleware` for context propagation, but that didn't change the behavior. Here's how I set it up: ```go import ( "github.com/grpc-ecosystem/go-grpc-middleware" "github.com/grpc-ecosystem/go-grpc-middleware/tracing/opentelemetry" ) opts := []grpc.ServerOption{ grpc_middleware.WithUnaryServerChain( otelgrpc.UnaryServerInterceptor(), ), } grpcServer := grpc.NewServer(opts...) ``` Is there something I'm missing in terms of configuration or best practices for ensuring that context is propagated correctly in a gRPC setup? Any suggestions would be greatly appreciated! I'd really appreciate any guidance on this. The stack includes Go and several other technologies. Is there a better approach? I'm working with Go in a Docker container on Ubuntu 20.04. Hoping someone can shed some light on this. My development environment is Windows 11. Thanks in advance!