grpc: add ability to compile with or without tracing

server.go

@@ -33,8 +33,6 @@ import (
 	"sync/atomic"
 	"time"
 
-	"golang.org/x/net/trace"
-
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/encoding"
@@ -131,7 +129,7 @@ type Server struct {
 	drain    bool
 	cv       *sync.Cond              // signaled when connections close for GracefulStop
 	services map[string]*serviceInfo // service name -> service info
-	events   trace.EventLog
+	events   traceEventLog
 
 	quit               *grpcsync.Event
 	done               *grpcsync.Event
@@ -670,7 +668,7 @@ func NewServer(opt ...ServerOption) *Server {
 	s.cv = sync.NewCond(&s.mu)
 	if EnableTracing {
 		_, file, line, _ := runtime.Caller(1)
-		s.events = trace.NewEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
+		s.events = newTraceEventLog("grpc.Server", fmt.Sprintf("%s:%d", file, line))
 	}
 
 	if s.opts.numServerWorkers > 0 {
@@ -1734,8 +1732,8 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 	ctx = contextWithServer(ctx, s)
 	var ti *traceInfo
 	if EnableTracing {
-		tr := trace.New("grpc.Recv."+methodFamily(stream.Method()), stream.Method())
-		ctx = trace.NewContext(ctx, tr)
+		tr := newTrace("grpc.Recv."+methodFamily(stream.Method()), stream.Method())
+		ctx = newTraceContext(ctx, tr)
 		ti = &traceInfo{
 			tr: tr,
 			firstLine: firstLine{

stream.go

@@ -27,7 +27,6 @@ import (
 	"sync"
 	"time"
 
-	"golang.org/x/net/trace"
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/encoding"
@@ -431,7 +430,7 @@ func (cs *clientStream) newAttemptLocked(isTransparent bool) (*csAttempt, error)
 	var trInfo *traceInfo
 	if EnableTracing {
 		trInfo = &traceInfo{
-			tr: trace.New("grpc.Sent."+methodFamily(method), method),
+			tr: newTrace("grpc.Sent."+methodFamily(method), method),
 			firstLine: firstLine{
 				client: true,
 			},
@@ -440,7 +439,7 @@ func (cs *clientStream) newAttemptLocked(isTransparent bool) (*csAttempt, error)
 			trInfo.firstLine.deadline = time.Until(deadline)
 		}
 		trInfo.tr.LazyLog(&trInfo.firstLine, false)
-		ctx = trace.NewContext(ctx, trInfo.tr)
+		ctx = newTraceContext(ctx, trInfo.tr)
 	}
 
 	if cs.cc.parsedTarget.URL.Scheme == internal.GRPCResolverSchemeExtraMetadata {

trace.go

@@ -26,8 +26,6 @@ import (
 	"strings"
 	"sync"
 	"time"
-
-	"golang.org/x/net/trace"
 )
 
 // EnableTracing controls whether to trace RPCs using the golang.org/x/net/trace package.
@@ -44,9 +42,31 @@ func methodFamily(m string) string {
 	return m
 }
 
+// traceEventLog mirrors golang.org/x/net/trace.EventLog.
+//
+// It exists in order to avoid importing x/net/trace on grpcnotrace builds.
+type traceEventLog interface {
+	Printf(format string, a ...any)
+	Errorf(format string, a ...any)
+	Finish()
+}
+
+// traceLog mirrors golang.org/x/net/trace.Trace.
+//
+// It exists in order to avoid importing x/net/trace on grpcnotrace builds.
+type traceLog interface {
+	LazyLog(x fmt.Stringer, sensitive bool)
+	LazyPrintf(format string, a ...any)
+	SetError()
+	SetRecycler(f func(any))
+	SetTraceInfo(traceID, spanID uint64)
+	SetMaxEvents(m int)
+	Finish()
+}
+
 // traceInfo contains tracing information for an RPC.
 type traceInfo struct {
-	tr        trace.Trace
+	tr        traceLog
 	firstLine firstLine
 }
 

trace_notrace.go

@@ -0,0 +1,52 @@
+//go:build grpcnotrace
+
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+// grpcnotrace can be used to avoid importing golang.org/x/net/trace, which in
+// turn enables binaries using gRPC-Go for dead code elimination, which can
+// yield 10-15% improvements in binary size when tracing is not needed.
+
+import (
+	"context"
+	"fmt"
+)
+
+type notrace struct{}
+
+func (notrace) LazyLog(x fmt.Stringer, sensitive bool) {}
+func (notrace) LazyPrintf(format string, a ...any)     {}
+func (notrace) SetError()                              {}
+func (notrace) SetRecycler(f func(any))                {}
+func (notrace) SetTraceInfo(traceID, spanID uint64)    {}
+func (notrace) SetMaxEvents(m int)                     {}
+func (notrace) Finish()                                {}
+
+func newTrace(family, title string) traceLog {
+	return notrace{}
+}
+
+func newTraceContext(ctx context.Context, tr traceLog) context.Context {
+	return ctx
+}
+
+func newTraceEventLog(family, title string) traceEventLog {
+	return nil
+}

trace_withtrace.go

@@ -0,0 +1,39 @@
+//go:build !grpcnotrace
+
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"context"
+
+	t "golang.org/x/net/trace"
+)
+
+func newTrace(family, title string) traceLog {
+	return t.New(family, title)
+}
+
+func newTraceContext(ctx context.Context, tr traceLog) context.Context {
+	return t.NewContext(ctx, tr)
+}
+
+func newTraceEventLog(family, title string) traceEventLog {
+	return t.NewEventLog(family, title)
+}