kokizzu / jeager1

jaeger integration example with common protocols

jeager1

This is example how to use jaeger (typo '__') to trace between services. Since most of the examples on the internet already outdated (deprecated jaeger client or deprecated opentracing library).

docker-compose up -d

# http example
go run main.go httpA
curl -v localhost:3000

# grpc example
go run main.go grpcB
grpcurl -plaintext 127.0.0.1:3001 list
grpcurl -plaintext -d '{"name":"BBB"}' 127.0.0.1:3001 GrpcB.GetSomething 

# nats example, will publish a message when server start
go run main.go natsC 

open localhost:16686 to see the trace.

TODO

• log all request and response payload

Special Thanks

• thetooth - fixing NATS traceID/spanID problem

jeager1's Issues

Stackoverflow suffering

I saw your question, took me basically all day to figure this out lmao. The go.opentelemetry.io/otel/[email protected]/trace.go file has the definitions for the context right, you can call MarshalJSON and have it spit something that looks useful but here's the thing. There is no equivalent unmarshalling function and the output is a string while the internal format is a fixed length byte array...

So to get it to work just dump the trace and span IDs into whatever format you like:

// Attach telemetry headers
headers := nats.Header{}
headers.Set(otelTraceID, span.SpanContext().TraceID().String())
headers.Set(otelSpanID, span.SpanContext().SpanID().String())

Then on the receive side you have to rebuild it manually into a SpanContext:

func getParentContext(msg *nats.Msg) (spanContext trace.SpanContext, err error) {
	var traceID trace.TraceID
	traceID, err = trace.TraceIDFromHex(msg.Header.Get(otelTraceID))
	if err != nil {
		return spanContext, err
	}
	var spanID trace.SpanID
	spanID, err = trace.SpanIDFromHex(msg.Header.Get(otelSpanID))
	if err != nil {
		return spanContext, err
	}
	var spanContextConfig trace.SpanContextConfig
	spanContextConfig.TraceID = traceID
	spanContextConfig.SpanID = spanID
	spanContextConfig.TraceFlags = 01
	spanContextConfig.Remote = true
	spanContext = trace.NewSpanContext(spanContextConfig)
	return spanContext, nil
}

Then actually use it:

remoteCtx, err := getParentContext(msg)
if err != nil {
	logrus.Fatal(err)
}

_, span := otel.Tracer(fqpn).Start(trace.ContextWithRemoteSpanContext(context.Background(), remoteCtx), msg.Subject)
defer span.End()