Added SpanKind for gRPC Server and Client

contrib/google.golang.org/grpc/client.go

@@ -29,6 +29,7 @@ func (cs *clientStream) RecvMsg(m interface{}) (err error) {
 			cs.cfg.clientServiceName(),
 			cs.cfg.analyticsRate,
 		)
+
 		if p, ok := peer.FromContext(cs.Context()); ok {
 			setSpanTargetFromPeer(span, *p)
 		}
@@ -47,6 +48,7 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 			cs.cfg.clientServiceName(),
 			cs.cfg.analyticsRate,
 		)
+
 		if p, ok := peer.FromContext(cs.Context()); ok {
 			setSpanTargetFromPeer(span, *p)
 		}
@@ -142,6 +144,9 @@ func doClientRequest(
 		cfg.clientServiceName(),
 		cfg.analyticsRate,
 	)
+
+	span.SetTag(ext.SpanKind, ext.SpanKindClient)
+
 	ctx = injectSpanIntoContext(ctx)
 
 	// fill in the peer so we can add it to the tags

contrib/google.golang.org/grpc/server.go

@@ -4,6 +4,7 @@ import (
 	context "golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"github.com/signalfx/signalfx-go-tracing/ddtrace"
+	"github.com/signalfx/signalfx-go-tracing/ddtrace/ext"
 )
 
 type serverStream struct {
@@ -34,6 +35,7 @@ func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 			ss.cfg.serverServiceName(),
 			ss.cfg.analyticsRate,
 		)
+
 		defer func() { finishWithError(span, err, ss.cfg) }()
 	}
 	err = ss.ServerStream.RecvMsg(m)
@@ -49,6 +51,7 @@ func (ss *serverStream) SendMsg(m interface{}) (err error) {
 			ss.cfg.serverServiceName(),
 			ss.cfg.analyticsRate,
 		)
+
 		defer func() { finishWithError(span, err, ss.cfg) }()
 	}
 	err = ss.ServerStream.SendMsg(m)
@@ -78,6 +81,9 @@ func StreamServerInterceptor(opts ...Option) grpc.StreamServerInterceptor {
 				cfg.serviceName,
 				cfg.analyticsRate,
 			)
+
+			span.SetTag(ext.SpanKind, ext.SpanKindServer)
+
 			defer func() { finishWithError(span, err, cfg) }()
 		}
 
@@ -109,6 +115,9 @@ func UnaryServerInterceptor(opts ...Option) grpc.UnaryServerInterceptor {
 			cfg.serverServiceName(),
 			cfg.analyticsRate,
 		)
+
+		span.SetTag(ext.SpanKind, ext.SpanKindServer)
+
 		resp, err := handler(ctx, req)
 		finishWithError(span, err, cfg)
 		return resp, err