comments etc

balancer/grpclb/grpclb_remote_balancer.go

@@ -35,7 +35,6 @@ import (
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials/insecure"
 	"google.golang.org/grpc/internal/backoff"
-	"google.golang.org/grpc/internal/channelz"
 	imetadata "google.golang.org/grpc/internal/metadata"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
@@ -240,9 +239,7 @@ func (lb *lbBalancer) newRemoteBalancerCCWrapper() {
 	// Explicitly set pickfirst as the balancer.
 	dopts = append(dopts, grpc.WithDefaultServiceConfig(`{"loadBalancingPolicy":"pick_first"}`))
 	dopts = append(dopts, grpc.WithResolvers(lb.manualResolver))
-	if channelz.IsOn() {
-		dopts = append(dopts, grpc.WithChannelzParentID(lb.opt.ChannelzParentID))
-	}
+	dopts = append(dopts, grpc.WithChannelzParentID(lb.opt.ChannelzParentID))
 
 	// Enable Keepalive for grpclb client.
 	dopts = append(dopts, grpc.WithKeepaliveParams(keepalive.ClientParameters{

channelz/channelz.go

@@ -31,5 +31,6 @@ package channelz
 
 import "google.golang.org/grpc/internal/channelz"
 
-// TODO(easwars): Add comment.
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
 type Identifier = channelz.Identifier

clientconn.go

@@ -38,6 +38,7 @@ import (
 	"google.golang.org/grpc/internal/backoff"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
+	"google.golang.org/grpc/internal/pretty"
 	iresolver "google.golang.org/grpc/internal/resolver"
 	"google.golang.org/grpc/internal/transport"
 	"google.golang.org/grpc/keepalive"
@@ -1320,7 +1321,7 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 	newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, addr, copts, func() { prefaceReceived.Fire() }, onGoAway, onClose)
 	if err != nil {
 		// newTr is either nil, or closed.
-		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v. Err: %v", addr, err)
+		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s. Err: %v", pretty.ToJSON(addr), err)
 		return err
 	}
 
@@ -1333,7 +1334,7 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 		newTr.Close(transport.ErrConnClosing)
 		if connectCtx.Err() == context.DeadlineExceeded {
 			err := errors.New("failed to receive server preface within timeout")
-			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v: %v", addr, err)
+			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s: %v", pretty.ToJSON(addr), err)
 			return err
 		}
 		return nil

internal/channelz/id.go

@@ -20,34 +20,45 @@ package channelz
 
 import "fmt"
 
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
 type Identifier struct {
 	typ RefChannelType
 	id  int64
 	str string
 	pid *Identifier
 }
 
+// Type returns the entity type corresponding to id.
 func (id *Identifier) Type() RefChannelType {
 	if id == nil {
 		return RefUnknown
 	}
 	return id.typ
 }
 
+// Int returns the integer identifier corresponding to id.
 func (id *Identifier) Int() int64 {
 	if id == nil {
 		return 0
 	}
 	return id.id
 }
 
+// String returns a string representation of the entity corresponding to id.
+
+// This includes some information about the parent as well. Examples:
+// Top-level channel: [Channel #channel-number]
+// Nested channel: 		[Channel #parent-channel-number Channel #channel-number]
+// Sub channel: 			[Channel #parent-channel SubChannel #subchannel-number]
 func (id *Identifier) String() string {
 	if id == nil {
 		return ""
 	}
 	return id.str
 }
 
+// Equal returns true if other is the same as id.
 func (id *Identifier) Equal(other *Identifier) bool {
 	if (id != nil) != (other != nil) {
 		return false
@@ -58,6 +69,8 @@ func (id *Identifier) Equal(other *Identifier) bool {
 	return id.typ == other.typ && id.id == other.id && id.pid == other.pid
 }
 
+// NewIdentifierForTesting returns a new opaque identifier to be used only for
+// testing purposes.
 func NewIdentifierForTesting(typ RefChannelType, id int64, pid *Identifier) *Identifier {
 	return newIdentifer(typ, id, pid)
 }

internal/channelz/logging.go

@@ -26,9 +26,13 @@ import (
 
 var logger = grpclog.Component("channelz")
 
+func withParens(id *Identifier) string {
+	return "[" + id.String() + "] "
+}
+
 // Info logs and adds a trace event if channelz is on.
 func Info(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprint(args...)
+	msg := withParens(id) + fmt.Sprint(args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,
@@ -41,7 +45,7 @@ func Info(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
 
 // Infof logs and adds a trace event if channelz is on.
 func Infof(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprintf(format, args...)
+	msg := withParens(id) + fmt.Sprintf(format, args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,
@@ -54,7 +58,7 @@ func Infof(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...inter
 
 // Warning logs and adds a trace event if channelz is on.
 func Warning(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprint(args...)
+	msg := withParens(id) + fmt.Sprint(args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,
@@ -67,7 +71,7 @@ func Warning(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
 
 // Warningf logs and adds a trace event if channelz is on.
 func Warningf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprintf(format, args...)
+	msg := withParens(id) + fmt.Sprintf(format, args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,
@@ -80,7 +84,7 @@ func Warningf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...in
 
 // Error logs and adds a trace event if channelz is on.
 func Error(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprint(args...)
+	msg := withParens(id) + fmt.Sprint(args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,
@@ -93,7 +97,7 @@ func Error(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
 
 // Errorf logs and adds a trace event if channelz is on.
 func Errorf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := "[" + id.String() + "] " + fmt.Sprintf(format, args...)
+	msg := withParens(id) + fmt.Sprintf(format, args...)
 	if IsOn() {
 		AddTraceEvent(l, id, 1, &TraceEventDesc{
 			Desc:     msg,

internal/transport/http2_client.go

@@ -351,14 +351,9 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		}
 		t.statsHandler.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
-		var err error
-		t.channelzID, err = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
-		if err != nil {
-			// TODO(easwars): See if you need to return a more meaningful error.
-			// TODO(easwars): Also, check if the transport needs to be closed before returning.
-			return nil, err
-		}
+	t.channelzID, err = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
+	if err != nil {
+		return nil, err
 	}
 	if t.keepaliveEnabled {
 		t.kpDormancyCond = sync.NewCond(&t.mu)
@@ -904,9 +899,7 @@ func (t *http2Client) Close(err error) {
 	t.controlBuf.finish()
 	t.cancel()
 	t.conn.Close()
-	if channelz.IsOn() {
-		channelz.RemoveEntry(t.channelzID)
-	}
+	channelz.RemoveEntry(t.channelzID)
 	// Append info about previous goaways if there were any, since this may be important
 	// for understanding the root cause for this connection to be closed.
 	_, goAwayDebugMessage := t.GetGoAwayReason()

internal/transport/http2_server.go

@@ -275,14 +275,9 @@ func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport,
 		connBegin := &stats.ConnBegin{}
 		t.stats.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
-		var err error
-		t.channelzID, err = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
-		if err != nil {
-			// TODO(easwars): See if you need to return a more meaningful error.
-			// TODO(easwars): Also, check if the transport needs to be closed before returning.
-			return nil, err
-		}
+	t.channelzID, err = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
+	if err != nil {
+		return nil, err
 	}
 
 	t.connectionID = atomic.AddUint64(&serverConnectionCounter, 1)
@@ -1215,9 +1210,7 @@ func (t *http2Server) Close() {
 	if err := t.conn.Close(); err != nil && logger.V(logLevel) {
 		logger.Infof("transport: error closing conn during Close: %v", err)
 	}
-	if channelz.IsOn() {
-		channelz.RemoveEntry(t.channelzID)
-	}
+	channelz.RemoveEntry(t.channelzID)
 	// Cancel all active streams.
 	for _, s := range streams {
 		s.cancel()

server.go

@@ -584,9 +584,7 @@ func NewServer(opt ...ServerOption) *Server {
 		s.initServerWorkers()
 	}
 
-	if channelz.IsOn() {
-		s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
-	}
+	s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
 	return s
 }
 
@@ -724,9 +722,7 @@ func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
 
 func (l *listenSocket) Close() error {
 	err := l.Listener.Close()
-	if channelz.IsOn() {
-		channelz.RemoveEntry(l.channelzID)
-	}
+	channelz.RemoveEntry(l.channelzID)
 	return err
 }
 
@@ -737,52 +733,50 @@ func (l *listenSocket) Close() error {
 // this method returns.
 // Serve will return a non-nil error unless Stop or GracefulStop is called.
 func (s *Server) Serve(lis net.Listener) error {
-	s.mu.Lock()
-	s.printf("serving")
-	s.serve = true
-	if s.lis == nil {
-		// Serve called after Stop or GracefulStop.
-		s.mu.Unlock()
-		lis.Close()
-		return ErrServerStopped
-	}
+	if err := func() error { // Anonymous func to be able to defer the unlock.
+		s.mu.Lock()
+		defer s.mu.Unlock()
 
-	s.serveWG.Add(1)
-	defer func() {
-		s.serveWG.Done()
-		if s.quit.HasFired() {
-			// Stop or GracefulStop called; block until done and return nil.
-			<-s.done.Done()
+		s.printf("serving")
+		s.serve = true
+		if s.lis == nil {
+			lis.Close()
+			return ErrServerStopped
 		}
-	}()
 
-	ls := &listenSocket{Listener: lis}
-	s.lis[ls] = true
+		s.serveWG.Add(1)
+		defer func() {
+			s.serveWG.Done()
+			if s.quit.HasFired() {
+				// Stop or GracefulStop called; block until done and return nil.
+				<-s.done.Done()
+			}
+		}()
+
+		ls := &listenSocket{Listener: lis}
+		s.lis[ls] = true
 
-	if channelz.IsOn() {
 		var err error
 		ls.channelzID, err = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
 		if err != nil {
-			// TODO(easwars): See if you can defer this unlock somehow.
-			s.mu.Unlock()
 			lis.Close()
-			// TODO(easwars): return a more meaningful error.
 			return err
 		}
-	}
-	s.mu.Unlock()
 
-	defer func() {
-		s.mu.Lock()
-		if s.lis != nil && s.lis[ls] {
-			ls.Close()
-			delete(s.lis, ls)
-		}
-		s.mu.Unlock()
-	}()
+		defer func() {
+			s.mu.Lock()
+			if s.lis != nil && s.lis[ls] {
+				ls.Close()
+				delete(s.lis, ls)
+			}
+			s.mu.Unlock()
+		}()
+		return nil
+	}(); err != nil {
+		return err
+	}
 
 	var tempDelay time.Duration // how long to sleep on accept failure
-
 	for {
 		rawConn, err := lis.Accept()
 		if err != nil {
@@ -1717,11 +1711,7 @@ func (s *Server) Stop() {
 		s.done.Fire()
 	}()
 
-	s.channelzRemoveOnce.Do(func() {
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })
 
 	s.mu.Lock()
 	listeners := s.lis
@@ -1759,11 +1749,7 @@ func (s *Server) GracefulStop() {
 	s.quit.Fire()
 	defer s.done.Fire()
 
-	s.channelzRemoveOnce.Do(func() {
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })
 	s.mu.Lock()
 	if s.conns == nil {
 		s.mu.Unlock()