contrib/google.golang.org/grpc: fix race condition when setting metad…

…ata (#302)
DataDog · Aug 6, 2018 · 2ef3281 · 2ef3281
1 parent 888c7c4
commit 2ef3281
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/contrib/google.golang.org/grpc/client.go b/contrib/google.golang.org/grpc/client.go
@@ -162,7 +162,10 @@ func injectSpanIntoContext(ctx context.Context) context.Context {
 		return ctx
 	}
 	md, ok := metadata.FromIncomingContext(ctx)
-	if !ok {
+	if ok {
+		// we have to copy the metadata because its not safe to modify
+		md = md.Copy()
+	} else {
 		md = metadata.MD{}
 	}
 	if err := tracer.Inject(span.Context(), grpcutil.MDCarrier(md)); err != nil {