server: return better status for context err when writing header

internal/transport/http2_server.go

@@ -21,7 +21,6 @@ package transport
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -53,10 +52,10 @@ import (
 var (
 	// ErrIllegalHeaderWrite indicates that setting header is illegal because of
 	// the stream's state.
-	ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHeader was already called")
+	ErrIllegalHeaderWrite = status.Error(codes.Internal, "transport: SendHeader called multiple times")
 	// ErrHeaderListSizeLimitViolation indicates that the header list size is larger
 	// than the limit set by peer.
-	ErrHeaderListSizeLimitViolation = errors.New("transport: trying to send header list size larger than the limit set by peer")
+	ErrHeaderListSizeLimitViolation = status.Error(codes.Internal, "transport: trying to send header list size larger than the limit set by peer")
 )
 
 // serverConnectionCounter counts the number of connections a server has seen
@@ -931,11 +930,25 @@ func (t *http2Server) checkForHeaderListSize(it interface{}) bool {
 	return true
 }
 
+func (t *http2Server) streamContextErr(s *Stream) error {
+	select {
+	case <-t.done:
+		return ErrConnClosing
+	default:
+	}
+	return ContextErr(s.ctx.Err())
+}
+
 // WriteHeader sends the header metadata md back to the client.
 func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
-	if s.updateHeaderSent() || s.getState() == streamDone {
+	if s.updateHeaderSent() {
 		return ErrIllegalHeaderWrite
 	}
+
+	if s.getState() == streamDone {
+		return t.streamContextErr(s)
+	}
+
 	s.hdrMu.Lock()
 	if md.Len() > 0 {
 		if s.header.Len() > 0 {
@@ -946,7 +959,7 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 	}
 	if err := t.writeHeaderLocked(s); err != nil {
 		s.hdrMu.Unlock()
-		return err
+		return status.Convert(err).Err()
 	}
 	s.hdrMu.Unlock()
 	return nil
@@ -1062,23 +1075,12 @@ func (t *http2Server) WriteStatus(s *Stream, st *status.Status) error {
 func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) error {
 	if !s.isHeaderSent() { // Headers haven't been written yet.
 		if err := t.WriteHeader(s, nil); err != nil {
-			if _, ok := err.(ConnectionError); ok {
-				return err
-			}
-			// TODO(mmukhi, dfawley): Make sure this is the right code to return.
-			return status.Errorf(codes.Internal, "transport: %v", err)
+			return err
 		}
 	} else {
 		// Writing headers checks for this condition.
 		if s.getState() == streamDone {
-			// TODO(mmukhi, dfawley): Should the server write also return io.EOF?
-			s.cancel()
-			select {
-			case <-t.done:
-				return ErrConnClosing
-			default:
-			}
-			return ContextErr(s.ctx.Err())
+			return t.streamContextErr(s)
 		}
 	}
 	df := &dataFrame{
@@ -1088,12 +1090,7 @@ func (t *http2Server) Write(s *Stream, hdr []byte, data []byte, opts *Options) e
 		onEachWrite: t.setResetPingStrikes,
 	}
 	if err := s.wq.get(int32(len(hdr) + len(data))); err != nil {
-		select {
-		case <-t.done:
-			return ErrConnClosing
-		default:
-		}
-		return ContextErr(s.ctx.Err())
+		return t.streamContextErr(s)
 	}
 	return t.controlBuf.put(df)
 }
@@ -1229,10 +1226,6 @@ func (t *http2Server) Close() {
 
 // deleteStream deletes the stream s from transport's active streams.
 func (t *http2Server) deleteStream(s *Stream, eosReceived bool) {
-	// In case stream sending and receiving are invoked in separate
-	// goroutines (e.g., bi-directional streaming), cancel needs to be
-	// called to interrupt the potential blocking on other goroutines.
-	s.cancel()
 
 	t.mu.Lock()
 	if _, ok := t.activeStreams[s.id]; ok {
@@ -1254,6 +1247,11 @@ func (t *http2Server) deleteStream(s *Stream, eosReceived bool) {
 
 // finishStream closes the stream and puts the trailing headerFrame into controlbuf.
 func (t *http2Server) finishStream(s *Stream, rst bool, rstCode http2.ErrCode, hdr *headerFrame, eosReceived bool) {
+	// In case stream sending and receiving are invoked in separate
+	// goroutines (e.g., bi-directional streaming), cancel needs to be
+	// called to interrupt the potential blocking on other goroutines.
+	s.cancel()
+
 	oldState := s.swapState(streamDone)
 	if oldState == streamDone {
 		// If the stream was already done, return.
@@ -1273,6 +1271,11 @@ func (t *http2Server) finishStream(s *Stream, rst bool, rstCode http2.ErrCode, h
 
 // closeStream clears the footprint of a stream when the stream is not needed any more.
 func (t *http2Server) closeStream(s *Stream, rst bool, rstCode http2.ErrCode, eosReceived bool) {
+	// In case stream sending and receiving are invoked in separate
+	// goroutines (e.g., bi-directional streaming), cancel needs to be
+	// called to interrupt the potential blocking on other goroutines.
+	s.cancel()
+
 	s.swapState(streamDone)
 	t.deleteStream(s, eosReceived)
 

test/end2end_test.go

@@ -4964,8 +4964,8 @@ func testClientSendDataAfterCloseSend(t *testing.T, e env) {
 		}
 		if err := stream.SendMsg(nil); err == nil {
 			t.Error("expected error sending message on stream after stream closed due to illegal data")
-		} else if status.Code(err) != codes.Internal {
-			t.Errorf("expected internal error, instead received '%v'", err)
+		} else if status.Code(err) != codes.Canceled {
+			t.Errorf("expected cancel error, instead received '%v'", err)
 		}
 		return nil
 	}}