Go gRPC Opentracing Instrumentation
An attempt to use Opentracing with gRPC services. The official
grpc-opentracing library currently only supports tracing
unary calls. This library makes use of gRPC stats.Handler interface to add tracing to gRPC streams as well.
The obvious approach to add tracing would be to make use of gRPC interceptors. However, the current interceptor
interfaces lack the fuctionality to effectively add tracing information to the calls. Go gRPC has a built-in tracing
mechanism that hooks into x/net/trace, but, the captured data is not accessible from external code. This leads us to
the stats.Handler interface which is primarily designed for stats gathering but, in the process, gives us access to
all interesting events that happen during a RPC -- which can be used to gather the tracing information we need.
Usage
Grab the library:
go get github.com/charithe/otgrpc
Client side:
tracer := // Tracer implementation
th := otgrpc.NewTraceHandler(tracer)
conn, err := grpc.Dial(address, grpc.WithStatsHandler(th))
...Server side:
tracer := // Tracer implementation
th := otgrpc.NewTraceHandler(tracer)
server := grpc.NewServer(grpc.StatsHandler(th))
...Options
Limit tracing to methods of your choosing
tf := func(method string) bool {
return method == "/my.svc/my.method"
}
th := otgrpc.NewTraceHandler(tracer, orgrpc.WithTraceEnabledFunc(tf))Attach payloads as Span log events
th := otgrpc.NewTraceHandler(tracer, otgrpc.WithPayloadLogging())