client: include details about GOAWAYs in status messages

internal/transport/http2_client.go

@@ -115,6 +115,9 @@ type http2Client struct {
 	// goAwayReason records the http2.ErrCode and debug data received with the
 	// GoAway frame.
 	goAwayReason GoAwayReason
+	// goAwayDebugMessage contains a detailed human readable string about a
+	// GoAway frame, useful for error messages.
+	goAwayDebugMessage string
 	// A condition variable used to signal when the keepalive goroutine should
 	// go dormant. The condition for dormancy is based on the number of active
 	// streams and the `PermitWithoutStream` keepalive client parameter. And
@@ -872,6 +875,12 @@ func (t *http2Client) Close(err error) {
 	if channelz.IsOn() {
 		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()
+	if len(goAwayDebugMessage) > 0 {
+		err = fmt.Errorf("closing transport due to: %v, received prior goaway: %v", err, goAwayDebugMessage)
+	}
 	// Notify all active streams.
 	for _, s := range streams {
 		t.closeStream(s, err, false, http2.ErrCodeNo, status.New(codes.Unavailable, err.Error()), nil, false)
@@ -1146,7 +1155,7 @@ func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
 		}
 	}
 	id := f.LastStreamID
-	if id > 0 && id%2 != 1 {
+	if id > 0 && id%2 == 0 {
 		t.mu.Unlock()
 		t.Close(connectionErrorf(true, nil, "received goaway with non-zero even-numbered numbered stream id: %v", id))
 		return
@@ -1212,12 +1221,13 @@ func (t *http2Client) setGoAwayReason(f *http2.GoAwayFrame) {
 			t.goAwayReason = GoAwayTooManyPings
 		}
 	}
+	t.goAwayDebugMessage = fmt.Sprintf("code: %s, debug data: %v", f.ErrCode, string(f.DebugData()))
 }
 
-func (t *http2Client) GetGoAwayReason() GoAwayReason {
+func (t *http2Client) GetGoAwayReason() (GoAwayReason, string) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
-	return t.goAwayReason
+	return t.goAwayReason, t.goAwayDebugMessage
 }
 
 func (t *http2Client) handleWindowUpdate(f *http2.WindowUpdateFrame) {

internal/transport/keepalive_test.go

@@ -69,7 +69,7 @@ func (s) TestMaxConnectionIdle(t *testing.T) {
 		if !timeout.Stop() {
 			<-timeout.C
 		}
-		if reason := client.GetGoAwayReason(); reason != GoAwayNoReason {
+		if reason, _ := client.GetGoAwayReason(); reason != GoAwayNoReason {
 			t.Fatalf("GoAwayReason is %v, want %v", reason, GoAwayNoReason)
 		}
 	case <-timeout.C:
@@ -143,7 +143,7 @@ func (s) TestMaxConnectionAge(t *testing.T) {
 		if !timeout.Stop() {
 			<-timeout.C
 		}
-		if reason := client.GetGoAwayReason(); reason != GoAwayNoReason {
+		if reason, _ := client.GetGoAwayReason(); reason != GoAwayNoReason {
 			t.Fatalf("GoAwayReason is %v, want %v", reason, GoAwayNoReason)
 		}
 	case <-timeout.C:
@@ -403,7 +403,7 @@ func (s) TestKeepaliveClientFrequency(t *testing.T) {
 		if !timeout.Stop() {
 			<-timeout.C
 		}
-		if reason := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
+		if reason, _ := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
 			t.Fatalf("GoAwayReason is %v, want %v", reason, GoAwayTooManyPings)
 		}
 	case <-timeout.C:
@@ -448,7 +448,7 @@ func (s) TestKeepaliveServerEnforcementWithAbusiveClientNoRPC(t *testing.T) {
 		if !timeout.Stop() {
 			<-timeout.C
 		}
-		if reason := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
+		if reason, _ := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
 			t.Fatalf("GoAwayReason is %v, want %v", reason, GoAwayTooManyPings)
 		}
 	case <-timeout.C:
@@ -498,7 +498,7 @@ func (s) TestKeepaliveServerEnforcementWithAbusiveClientWithRPC(t *testing.T) {
 		if !timeout.Stop() {
 			<-timeout.C
 		}
-		if reason := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
+		if reason, _ := client.GetGoAwayReason(); reason != GoAwayTooManyPings {
 			t.Fatalf("GoAwayReason is %v, want %v", reason, GoAwayTooManyPings)
 		}
 	case <-timeout.C:

internal/transport/transport.go

@@ -656,8 +656,9 @@ type ClientTransport interface {
 	// HTTP/2).
 	GoAway() <-chan struct{}
 
-	// GetGoAwayReason returns the reason why GoAway frame was received.
-	GetGoAwayReason() GoAwayReason
+	// GetGoAwayReason returns the reason why GoAway frame was received, along
+	// with a human readable string with debug info.
+	GetGoAwayReason() (GoAwayReason, string)
 
 	// RemoteAddr returns the remote network address.
 	RemoteAddr() net.Addr

test/end2end_test.go

@@ -55,12 +55,14 @@ import (
 	"google.golang.org/grpc/health"
 	healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
 	healthpb "google.golang.org/grpc/health/grpc_health_v1"
+	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
 	"google.golang.org/grpc/internal/grpctest"
 	"google.golang.org/grpc/internal/stubserver"
 	"google.golang.org/grpc/internal/testutils"
 	"google.golang.org/grpc/internal/transport"
+	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
 	"google.golang.org/grpc/resolver"
@@ -1380,6 +1382,84 @@ func (s) TestDetailedConnectionCloseErrorPropagatesToRpcError(t *testing.T) {
 	close(rpcDoneOnClient)
 }
 
+func (s) TestDetailedGoawayErrorOnGracefulClosePropagatesToRPCError(t *testing.T) {
+	rpcDoneOnClient := make(chan struct{})
+	ss := &stubserver.StubServer{
+		FullDuplexCallF: func(stream testpb.TestService_FullDuplexCallServer) error {
+			<-rpcDoneOnClient
+			return status.Error(codes.Internal, "arbitrary status")
+		},
+	}
+	sopts := []grpc.ServerOption{
+		grpc.KeepaliveParams(keepalive.ServerParameters{
+			MaxConnectionAge:      time.Millisecond * 100,
+			MaxConnectionAgeGrace: time.Millisecond,
+		}),
+	}
+	if err := ss.Start(sopts); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	stream, err := ss.Client.FullDuplexCall(ctx)
+	if err != nil {
+		t.Fatalf("%v.FullDuplexCall = _, %v, want _, <nil>", ss.Client, err)
+	}
+	const expectedErrorMessageSubstring = "received prior goaway: code: NO_ERROR"
+	_, err = stream.Recv()
+	close(rpcDoneOnClient)
+	if err == nil || !strings.Contains(err.Error(), expectedErrorMessageSubstring) {
+		t.Fatalf("%v.Recv() = _, %v, want _, rpc error containing substring: %q", stream, err, expectedErrorMessageSubstring)
+	}
+}
+
+func (s) TestDetailedGoawayErrorOnAbruptClosePropagatesToRPCError(t *testing.T) {
+	// set the min keepalive time very low so that this test can take
+	// a reasonable amount of time
+	prev := internal.KeepaliveMinPingTime
+	internal.KeepaliveMinPingTime = time.Millisecond
+	defer func() { internal.KeepaliveMinPingTime = prev }()
+
+	rpcDoneOnClient := make(chan struct{})
+	ss := &stubserver.StubServer{
+		FullDuplexCallF: func(stream testpb.TestService_FullDuplexCallServer) error {
+			<-rpcDoneOnClient
+			return status.Error(codes.Internal, "arbitrary status")
+		},
+	}
+	sopts := []grpc.ServerOption{
+		grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
+			MinTime: time.Second * 1000, /* arbitrary, large value */
+		}),
+	}
+	dopts := []grpc.DialOption{
+		grpc.WithKeepaliveParams(keepalive.ClientParameters{
+			Time:                time.Millisecond,   /* should trigger "too many pings" error quickly */
+			Timeout:             time.Second * 1000, /* arbitrary, large value */
+			PermitWithoutStream: false,
+		}),
+	}
+	if err := ss.Start(sopts, dopts...); err != nil {
+		t.Fatalf("Error starting endpoint server: %v", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	stream, err := ss.Client.FullDuplexCall(ctx)
+	if err != nil {
+		t.Fatalf("%v.FullDuplexCall = _, %v, want _, <nil>", ss.Client, err)
+	}
+	const expectedErrorMessageSubstring = "received prior goaway: code: ENHANCE_YOUR_CALM, debug data: too_many_pings"
+	_, err = stream.Recv()
+	close(rpcDoneOnClient)
+	if err == nil || !strings.Contains(err.Error(), expectedErrorMessageSubstring) {
+		t.Fatalf("%v.Recv() = _, %v, want _, rpc error containing substring: |%v|", stream, err, expectedErrorMessageSubstring)
+	}
+}
+
 func (s) TestClientConnCloseAfterGoAwayWithActiveStream(t *testing.T) {
 	for _, e := range listTestEnv() {
 		if e.name == "handler-tls" {