Golang stats.On函數代碼示例

func (ss *serverStream) RecvMsg(m interface{}) (err error) {
	defer func() {
		if ss.trInfo != nil {
			ss.mu.Lock()
			if ss.trInfo.tr != nil {
				if err == nil {
					ss.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
				} else if err != io.EOF {
					ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
					ss.trInfo.tr.SetError()
				}
			}
			ss.mu.Unlock()
		}
	}()
	var inPayload *stats.InPayload
	if stats.On() {
		inPayload = &stats.InPayload{}
	}
	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxMsgSize, inPayload); err != nil {
		if err == io.EOF {
			return err
		}
		if err == io.ErrUnexpectedEOF {
			err = Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
		}
		return toRPCErr(err)
	}
	if inPayload != nil {
		stats.HandleRPC(ss.s.Context(), inPayload)
	}
	return nil
}

// Close kicks off the shutdown process of the transport. This should be called
// only once on a transport. Once it is called, the transport should not be
// accessed any more.
func (t *http2Client) Close() (err error) {
	t.mu.Lock()
	if t.state == closing {
		t.mu.Unlock()
		return
	}
	if t.state == reachable || t.state == draining {
		close(t.errorChan)
	}
	t.state = closing
	t.mu.Unlock()
	close(t.shutdownChan)
	err = t.conn.Close()
	t.mu.Lock()
	streams := t.activeStreams
	t.activeStreams = nil
	t.mu.Unlock()
	// Notify all active streams.
	for _, s := range streams {
		s.mu.Lock()
		if !s.headerDone {
			close(s.headerChan)
			s.headerDone = true
		}
		s.mu.Unlock()
		s.write(recvMsg{err: ErrConnClosing})
	}
	if stats.On() {
		connEnd := &stats.ConnEnd{
			Client: true,
		}
		stats.HandleConn(t.ctx, connEnd)
	}
	return
}

func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Stream, msg interface{}, cp Compressor, opts *transport.Options) error {
	var (
		cbuf       *bytes.Buffer
		outPayload *stats.OutPayload
	)
	if cp != nil {
		cbuf = new(bytes.Buffer)
	}
	if stats.On() {
		outPayload = &stats.OutPayload{}
	}
	p, err := encode(s.opts.codec, msg, cp, cbuf, outPayload)
	if err != nil {
		// This typically indicates a fatal issue (e.g., memory
		// corruption or hardware faults) the application program
		// cannot handle.
		//
		// TODO(zhaoq): There exist other options also such as only closing the
		// faulty stream locally and remotely (Other streams can keep going). Find
		// the optimal option.
		grpclog.Fatalf("grpc: Server failed to encode response %v", err)
	}
	err = t.Write(stream, p, opts)
	if err == nil && outPayload != nil {
		outPayload.SentTime = time.Now()
		stats.HandleRPC(stream.Context(), outPayload)
	}
	return err
}

// WriteStatus sends stream status to the client and terminates the stream.
// There is no further I/O operations being able to perform on this stream.
// TODO(zhaoq): Now it indicates the end of entire stream. Revisit if early
// OK is adopted.
func (t *http2Server) WriteStatus(s *Stream, statusCode codes.Code, statusDesc string) error {
	var headersSent, hasHeader bool
	s.mu.Lock()
	if s.state == streamDone {
		s.mu.Unlock()
		return nil
	}
	if s.headerOk {
		headersSent = true
	}
	if s.header.Len() > 0 {
		hasHeader = true
	}
	s.mu.Unlock()

	if !headersSent && hasHeader {
		t.WriteHeader(s, nil)
		headersSent = true
	}

	if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
		return err
	}
	t.hBuf.Reset()
	if !headersSent {
		t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
		t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
	}
	t.hEnc.WriteField(
		hpack.HeaderField{
			Name:  "grpc-status",
			Value: strconv.Itoa(int(statusCode)),
		})
	t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-message", Value: encodeGrpcMessage(statusDesc)})
	// Attach the trailer metadata.
	for k, v := range s.trailer {
		// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
		if isReservedHeader(k) {
			continue
		}
		for _, entry := range v {
			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
		}
	}
	bufLen := t.hBuf.Len()
	if err := t.writeHeaders(s, t.hBuf, true); err != nil {
		t.Close()
		return err
	}
	if stats.On() {
		outTrailer := &stats.OutTrailer{
			WireLength: bufLen,
		}
		stats.HandleRPC(s.Context(), outTrailer)
	}
	t.closeStream(s)
	t.writableChan <- 0
	return nil
}

func (cs *clientStream) SendMsg(m interface{}) (err error) {
	if cs.tracing {
		cs.mu.Lock()
		if cs.trInfo.tr != nil {
			cs.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
		}
		cs.mu.Unlock()
	}
	// TODO Investigate how to signal the stats handling party.
	// generate error stats if err != nil && err != io.EOF?
	defer func() {
		if err != nil {
			cs.finish(err)
		}
		if err == nil {
			return
		}
		if err == io.EOF {
			// Specialize the process for server streaming. SendMesg is only called
			// once when creating the stream object. io.EOF needs to be skipped when
			// the rpc is early finished (before the stream object is created.).
			// TODO: It is probably better to move this into the generated code.
			if !cs.desc.ClientStreams && cs.desc.ServerStreams {
				err = nil
			}
			return
		}
		if _, ok := err.(transport.ConnectionError); !ok {
			cs.closeTransportStream(err)
		}
		err = toRPCErr(err)
	}()
	var outPayload *stats.OutPayload
	if stats.On() {
		outPayload = &stats.OutPayload{
			Client: true,
		}
	}
	out, err := encode(cs.codec, m, cs.cp, cs.cbuf, outPayload)
	defer func() {
		if cs.cbuf != nil {
			cs.cbuf.Reset()
		}
	}()
	if err != nil {
		return Errorf(codes.Internal, "grpc: %v", err)
	}
	err = cs.t.Write(cs.s, out, &transport.Options{Last: false})
	if err == nil && outPayload != nil {
		outPayload.SentTime = time.Now()
		stats.HandleRPC(cs.statsCtx, outPayload)
	}
	return err
}

// WriteHeader sends the header metedata md back to the client.
func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
	s.mu.Lock()
	if s.headerOk || s.state == streamDone {
		s.mu.Unlock()
		return ErrIllegalHeaderWrite
	}
	s.headerOk = true
	if md.Len() > 0 {
		if s.header.Len() > 0 {
			s.header = metadata.Join(s.header, md)
		} else {
			s.header = md
		}
	}
	md = s.header
	s.mu.Unlock()
	if _, err := wait(s.ctx, nil, nil, t.shutdownChan, t.writableChan); err != nil {
		return err
	}
	t.hBuf.Reset()
	t.hEnc.WriteField(hpack.HeaderField{Name: ":status", Value: "200"})
	t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
	if s.sendCompress != "" {
		t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-encoding", Value: s.sendCompress})
	}
	for k, v := range md {
		if isReservedHeader(k) {
			// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
			continue
		}
		for _, entry := range v {
			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
		}
	}
	bufLen := t.hBuf.Len()
	if err := t.writeHeaders(s, t.hBuf, false); err != nil {
		return err
	}
	if stats.On() {
		outHeader := &stats.OutHeader{
			WireLength: bufLen,
		}
		stats.HandleRPC(s.Context(), outHeader)
	}
	t.writableChan <- 0
	return nil
}

// sendRequest writes out various information of an RPC such as Context and Message.
func sendRequest(ctx context.Context, codec Codec, compressor Compressor, callHdr *transport.CallHdr, t transport.ClientTransport, args interface{}, opts *transport.Options) (_ *transport.Stream, err error) {
	stream, err := t.NewStream(ctx, callHdr)
	if err != nil {
		return nil, err
	}
	defer func() {
		if err != nil {
			// If err is connection error, t will be closed, no need to close stream here.
			if _, ok := err.(transport.ConnectionError); !ok {
				t.CloseStream(stream, err)
			}
		}
	}()
	var (
		cbuf       *bytes.Buffer
		outPayload *stats.OutPayload
	)
	if compressor != nil {
		cbuf = new(bytes.Buffer)
	}
	if stats.On() {
		outPayload = &stats.OutPayload{
			Client: true,
		}
	}
	outBuf, err := encode(codec, args, compressor, cbuf, outPayload)
	if err != nil {
		return nil, Errorf(codes.Internal, "grpc: %v", err)
	}
	err = t.Write(stream, outBuf, opts)
	if err == nil && outPayload != nil {
		outPayload.SentTime = time.Now()
		stats.Handle(ctx, outPayload)
	}
	// t.NewStream(...) could lead to an early rejection of the RPC (e.g., the service/method
	// does not exist.) so that t.Write could get io.EOF from wait(...). Leave the following
	// recvResponse to get the final status.
	if err != nil && err != io.EOF {
		return nil, err
	}
	// Sent successfully.
	return stream, nil
}

// Close starts shutting down the http2Server transport.
// TODO(zhaoq): Now the destruction is not blocked on any pending streams. This
// could cause some resource issue. Revisit this later.
func (t *http2Server) Close() (err error) {
	t.mu.Lock()
	if t.state == closing {
		t.mu.Unlock()
		return errors.New("transport: Close() was already called")
	}
	t.state = closing
	streams := t.activeStreams
	t.activeStreams = nil
	t.mu.Unlock()
	close(t.shutdownChan)
	err = t.conn.Close()
	// Cancel all active streams.
	for _, s := range streams {
		s.cancel()
	}
	if stats.On() {
		connEnd := &stats.ConnEnd{}
		stats.HandleConn(t.ctx, connEnd)
	}
	return
}

// recvResponse receives and parses an RPC response.
// On error, it returns the error and indicates whether the call should be retried.
//
// TODO(zhaoq): Check whether the received message sequence is valid.
// TODO ctx is used for stats collection and processing. It is the context passed from the application.
func recvResponse(ctx context.Context, dopts dialOptions, t transport.ClientTransport, c *callInfo, stream *transport.Stream, reply interface{}) (err error) {
	// Try to acquire header metadata from the server if there is any.
	defer func() {
		if err != nil {
			if _, ok := err.(transport.ConnectionError); !ok {
				t.CloseStream(stream, err)
			}
		}
	}()
	c.headerMD, err = stream.Header()
	if err != nil {
		return
	}
	p := &parser{r: stream}
	var inPayload *stats.InPayload
	if stats.On() {
		inPayload = &stats.InPayload{
			Client: true,
		}
	}
	for {
		if err = recv(p, dopts.codec, stream, dopts.dc, reply, math.MaxInt32, inPayload); err != nil {
			if err == io.EOF {
				break
			}
			return
		}
	}
	if inPayload != nil && err == io.EOF && stream.StatusCode() == codes.OK {
		// TODO in the current implementation, inTrailer may be handled before inPayload in some cases.
		// Fix the order if necessary.
		stats.Handle(ctx, inPayload)
	}
	c.trailerMD = stream.Trailer()
	return nil
}

func TestStartStop(t *testing.T) {
	stats.RegisterRPCHandler(nil)
	stats.RegisterConnHandler(nil)
	stats.Start()
	if stats.On() {
		t.Fatalf("stats.Start() with nil handler, stats.On() = true, want false")
	}

	stats.RegisterRPCHandler(func(ctx context.Context, s stats.RPCStats) {})
	stats.RegisterConnHandler(nil)
	stats.Start()
	if !stats.On() {
		t.Fatalf("stats.Start() with non-nil handler, stats.On() = false, want true")
	}
	stats.Stop()

	stats.RegisterRPCHandler(nil)
	stats.RegisterConnHandler(func(ctx context.Context, s stats.ConnStats) {})
	stats.Start()
	if !stats.On() {
		t.Fatalf("stats.Start() with non-nil conn handler, stats.On() = false, want true")
	}
	stats.Stop()

	stats.RegisterRPCHandler(func(ctx context.Context, s stats.RPCStats) {})
	stats.RegisterConnHandler(func(ctx context.Context, s stats.ConnStats) {})
	if stats.On() {
		t.Fatalf("after stats.RegisterRPCHandler(), stats.On() = true, want false")
	}
	stats.Start()
	if !stats.On() {
		t.Fatalf("after stats.Start(_), stats.On() = false, want true")
	}

	stats.Stop()
	if stats.On() {
		t.Fatalf("after stats.Stop(), stats.On() = true, want false")
	}
}

// newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
// returned if something goes wrong.
func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
	framer := newFramer(conn)
	// Send initial settings as connection preface to client.
	var settings []http2.Setting
	// TODO(zhaoq): Have a better way to signal "no limit" because 0 is
	// permitted in the HTTP2 spec.
	maxStreams := config.MaxStreams
	if maxStreams == 0 {
		maxStreams = math.MaxUint32
	} else {
		settings = append(settings, http2.Setting{
			ID:  http2.SettingMaxConcurrentStreams,
			Val: maxStreams,
		})
	}
	if initialWindowSize != defaultWindowSize {
		settings = append(settings, http2.Setting{
			ID:  http2.SettingInitialWindowSize,
			Val: uint32(initialWindowSize)})
	}
	if err := framer.writeSettings(true, settings...); err != nil {
		return nil, connectionErrorf(true, err, "transport: %v", err)
	}
	// Adjust the connection flow control window if needed.
	if delta := uint32(initialConnWindowSize - defaultWindowSize); delta > 0 {
		if err := framer.writeWindowUpdate(true, 0, delta); err != nil {
			return nil, connectionErrorf(true, err, "transport: %v", err)
		}
	}
	var buf bytes.Buffer
	t := &http2Server{
		ctx:             context.Background(),
		conn:            conn,
		remoteAddr:      conn.RemoteAddr(),
		localAddr:       conn.LocalAddr(),
		authInfo:        config.AuthInfo,
		framer:          framer,
		hBuf:            &buf,
		hEnc:            hpack.NewEncoder(&buf),
		maxStreams:      maxStreams,
		inTapHandle:     config.InTapHandle,
		controlBuf:      newRecvBuffer(),
		fc:              &inFlow{limit: initialConnWindowSize},
		sendQuotaPool:   newQuotaPool(defaultWindowSize),
		state:           reachable,
		writableChan:    make(chan int, 1),
		shutdownChan:    make(chan struct{}),
		activeStreams:   make(map[uint32]*Stream),
		streamSendQuota: defaultWindowSize,
	}
	if stats.On() {
		t.ctx = stats.TagConn(t.ctx, &stats.ConnTagInfo{
			RemoteAddr: t.remoteAddr,
			LocalAddr:  t.localAddr,
		})
		connBegin := &stats.ConnBegin{}
		stats.HandleConn(t.ctx, connBegin)
	}
	go t.controller()
	t.writableChan <- 0
	return t, nil
}

func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (e error) {
	c := defaultCallInfo
	for _, o := range opts {
		if err := o.before(&c); err != nil {
			return toRPCErr(err)
		}
	}
	defer func() {
		for _, o := range opts {
			o.after(&c)
		}
	}()
	if EnableTracing {
		c.traceInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
		defer c.traceInfo.tr.Finish()
		c.traceInfo.firstLine.client = true
		if deadline, ok := ctx.Deadline(); ok {
			c.traceInfo.firstLine.deadline = deadline.Sub(time.Now())
		}
		c.traceInfo.tr.LazyLog(&c.traceInfo.firstLine, false)
		// TODO(dsymonds): Arrange for c.traceInfo.firstLine.remoteAddr to be set.
		defer func() {
			if e != nil {
				c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{e}}, true)
				c.traceInfo.tr.SetError()
			}
		}()
	}
	if stats.On() {
		begin := &stats.Begin{
			Client:    true,
			BeginTime: time.Now(),
			FailFast:  c.failFast,
		}
		stats.Handle(ctx, begin)
	}
	defer func() {
		if stats.On() {
			end := &stats.End{
				Client:  true,
				EndTime: time.Now(),
				Error:   e,
			}
			stats.Handle(ctx, end)
		}
	}()
	topts := &transport.Options{
		Last:  true,
		Delay: false,
	}
	for {
		var (
			err    error
			t      transport.ClientTransport
			stream *transport.Stream
			// Record the put handler from Balancer.Get(...). It is called once the
			// RPC has completed or failed.
			put func()
		)
		// TODO(zhaoq): Need a formal spec of fail-fast.
		callHdr := &transport.CallHdr{
			Host:   cc.authority,
			Method: method,
		}
		if cc.dopts.cp != nil {
			callHdr.SendCompress = cc.dopts.cp.Type()
		}
		gopts := BalancerGetOptions{
			BlockingWait: !c.failFast,
		}
		t, put, err = cc.getTransport(ctx, gopts)
		if err != nil {
			// TODO(zhaoq): Probably revisit the error handling.
			if _, ok := err.(*rpcError); ok {
				return err
			}
			if err == errConnClosing || err == errConnUnavailable {
				if c.failFast {
					return Errorf(codes.Unavailable, "%v", err)
				}
				continue
			}
			// All the other errors are treated as Internal errors.
			return Errorf(codes.Internal, "%v", err)
		}
		if c.traceInfo.tr != nil {
			c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
		}
		stream, err = sendRequest(ctx, cc.dopts.codec, cc.dopts.cp, callHdr, t, args, topts)
		if err != nil {
			if put != nil {
				put()
				put = nil
			}
			// Retry a non-failfast RPC when
			// i) there is a connection error; or
			// ii) the server started to drain before this RPC was initiated.
			if _, ok := err.(transport.ConnectionError); ok || err == transport.ErrStreamDrain {
				if c.failFast {
					return toRPCErr(err)
//.........這裏部分代碼省略.........

func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, sd *StreamDesc, trInfo *traceInfo) (err error) {
	if stats.On() {
		begin := &stats.Begin{
			BeginTime: time.Now(),
		}
		stats.HandleRPC(stream.Context(), begin)
	}
	defer func() {
		if stats.On() {
			end := &stats.End{
				EndTime: time.Now(),
			}
			if err != nil && err != io.EOF {
				end.Error = toRPCErr(err)
			}
			stats.HandleRPC(stream.Context(), end)
		}
	}()
	if s.opts.cp != nil {
		stream.SetSendCompress(s.opts.cp.Type())
	}
	ss := &serverStream{
		t:          t,
		s:          stream,
		p:          &parser{r: stream},
		codec:      s.opts.codec,
		cp:         s.opts.cp,
		dc:         s.opts.dc,
		maxMsgSize: s.opts.maxMsgSize,
		trInfo:     trInfo,
	}
	if ss.cp != nil {
		ss.cbuf = new(bytes.Buffer)
	}
	if trInfo != nil {
		trInfo.tr.LazyLog(&trInfo.firstLine, false)
		defer func() {
			ss.mu.Lock()
			if err != nil && err != io.EOF {
				ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
				ss.trInfo.tr.SetError()
			}
			ss.trInfo.tr.Finish()
			ss.trInfo.tr = nil
			ss.mu.Unlock()
		}()
	}
	var appErr error
	if s.opts.streamInt == nil {
		appErr = sd.Handler(srv.server, ss)
	} else {
		info := &StreamServerInfo{
			FullMethod:     stream.Method(),
			IsClientStream: sd.ClientStreams,
			IsServerStream: sd.ServerStreams,
		}
		appErr = s.opts.streamInt(srv.server, ss, info, sd.Handler)
	}
	if appErr != nil {
		if err, ok := appErr.(*rpcError); ok {
			ss.statusCode = err.code
			ss.statusDesc = err.desc
		} else if err, ok := appErr.(transport.StreamError); ok {
			ss.statusCode = err.Code
			ss.statusDesc = err.Desc
		} else {
			ss.statusCode = convertCode(appErr)
			ss.statusDesc = appErr.Error()
		}
	}
	if trInfo != nil {
		ss.mu.Lock()
		if ss.statusCode != codes.OK {
			ss.trInfo.tr.LazyLog(stringer(ss.statusDesc), true)
			ss.trInfo.tr.SetError()
		} else {
			ss.trInfo.tr.LazyLog(stringer("OK"), false)
		}
		ss.mu.Unlock()
	}
	errWrite := t.WriteStatus(ss.s, ss.statusCode, ss.statusDesc)
	if ss.statusCode != codes.OK {
		return Errorf(ss.statusCode, ss.statusDesc)
	}
	return errWrite

}

// operateHeader takes action on the decoded headers.
func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (close bool) {
	buf := newRecvBuffer()
	s := &Stream{
		id:  frame.Header().StreamID,
		st:  t,
		buf: buf,
		fc:  &inFlow{limit: initialWindowSize},
	}

	var state decodeState
	for _, hf := range frame.Fields {
		state.processHeaderField(hf)
	}
	if err := state.err; err != nil {
		if se, ok := err.(StreamError); ok {
			t.controlBuf.put(&resetStream{s.id, statusCodeConvTab[se.Code]})
		}
		return
	}

	if frame.StreamEnded() {
		// s is just created by the caller. No lock needed.
		s.state = streamReadDone
	}
	s.recvCompress = state.encoding
	if state.timeoutSet {
		s.ctx, s.cancel = context.WithTimeout(t.ctx, state.timeout)
	} else {
		s.ctx, s.cancel = context.WithCancel(t.ctx)
	}
	pr := &peer.Peer{
		Addr: t.remoteAddr,
	}
	// Attach Auth info if there is any.
	if t.authInfo != nil {
		pr.AuthInfo = t.authInfo
	}
	s.ctx = peer.NewContext(s.ctx, pr)
	// Cache the current stream to the context so that the server application
	// can find out. Required when the server wants to send some metadata
	// back to the client (unary call only).
	s.ctx = newContextWithStream(s.ctx, s)
	// Attach the received metadata to the context.
	if len(state.mdata) > 0 {
		s.ctx = metadata.NewContext(s.ctx, state.mdata)
	}

	s.dec = &recvBufferReader{
		ctx:  s.ctx,
		recv: s.buf,
	}
	s.recvCompress = state.encoding
	s.method = state.method
	if t.inTapHandle != nil {
		var err error
		info := &tap.Info{
			FullMethodName: state.method,
		}
		s.ctx, err = t.inTapHandle(s.ctx, info)
		if err != nil {
			// TODO: Log the real error.
			t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
			return
		}
	}
	t.mu.Lock()
	if t.state != reachable {
		t.mu.Unlock()
		return
	}
	if uint32(len(t.activeStreams)) >= t.maxStreams {
		t.mu.Unlock()
		t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
		return
	}
	if s.id%2 != 1 || s.id <= t.maxStreamID {
		t.mu.Unlock()
		// illegal gRPC stream id.
		grpclog.Println("transport: http2Server.HandleStreams received an illegal stream id: ", s.id)
		return true
	}
	t.maxStreamID = s.id
	s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
	t.activeStreams[s.id] = s
	t.mu.Unlock()
	s.windowHandler = func(n int) {
		t.updateWindow(s, uint32(n))
	}
	s.ctx = traceCtx(s.ctx, s.method)
	if stats.On() {
		s.ctx = stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method})
		inHeader := &stats.InHeader{
			FullMethod:  s.method,
			RemoteAddr:  t.remoteAddr,
			LocalAddr:   t.localAddr,
			Compression: s.recvCompress,
			WireLength:  int(frame.Header().Length),
		}
		stats.HandleRPC(s.ctx, inHeader)
//.........這裏部分代碼省略.........

// newHTTP2Client constructs a connected ClientTransport to addr based on HTTP2
// and starts to receive messages on it. Non-nil error returns if construction
// fails.
func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (_ ClientTransport, err error) {
	scheme := "http"
	conn, err := dial(ctx, opts.Dialer, addr.Addr)
	if err != nil {
		if opts.FailOnNonTempDialError {
			return nil, connectionErrorf(isTemporary(err), err, "transport: %v", err)
		}
		return nil, connectionErrorf(true, err, "transport: %v", err)
	}
	// Any further errors will close the underlying connection
	defer func(conn net.Conn) {
		if err != nil {
			conn.Close()
		}
	}(conn)
	var authInfo credentials.AuthInfo
	if creds := opts.TransportCredentials; creds != nil {
		scheme = "https"
		conn, authInfo, err = creds.ClientHandshake(ctx, addr.Addr, conn)
		if err != nil {
			// Credentials handshake errors are typically considered permanent
			// to avoid retrying on e.g. bad certificates.
			temp := isTemporary(err)
			return nil, connectionErrorf(temp, err, "transport: %v", err)
		}
	}
	ua := primaryUA
	if opts.UserAgent != "" {
		ua = opts.UserAgent + " " + ua
	}
	var buf bytes.Buffer
	t := &http2Client{
		ctx:        ctx,
		target:     addr.Addr,
		userAgent:  ua,
		md:         addr.Metadata,
		conn:       conn,
		remoteAddr: conn.RemoteAddr(),
		localAddr:  conn.LocalAddr(),
		authInfo:   authInfo,
		// The client initiated stream id is odd starting from 1.
		nextID:          1,
		writableChan:    make(chan int, 1),
		shutdownChan:    make(chan struct{}),
		errorChan:       make(chan struct{}),
		goAway:          make(chan struct{}),
		framer:          newFramer(conn),
		hBuf:            &buf,
		hEnc:            hpack.NewEncoder(&buf),
		controlBuf:      newRecvBuffer(),
		fc:              &inFlow{limit: initialConnWindowSize},
		sendQuotaPool:   newQuotaPool(defaultWindowSize),
		scheme:          scheme,
		state:           reachable,
		activeStreams:   make(map[uint32]*Stream),
		creds:           opts.PerRPCCredentials,
		maxStreams:      math.MaxInt32,
		streamSendQuota: defaultWindowSize,
	}
	// Start the reader goroutine for incoming message. Each transport has
	// a dedicated goroutine which reads HTTP2 frame from network. Then it
	// dispatches the frame to the corresponding stream entity.
	go t.reader()
	// Send connection preface to server.
	n, err := t.conn.Write(clientPreface)
	if err != nil {
		t.Close()
		return nil, connectionErrorf(true, err, "transport: %v", err)
	}
	if n != len(clientPreface) {
		t.Close()
		return nil, connectionErrorf(true, err, "transport: preface mismatch, wrote %d bytes; want %d", n, len(clientPreface))
	}
	if initialWindowSize != defaultWindowSize {
		err = t.framer.writeSettings(true, http2.Setting{
			ID:  http2.SettingInitialWindowSize,
			Val: uint32(initialWindowSize),
		})
	} else {
		err = t.framer.writeSettings(true)
	}
	if err != nil {
		t.Close()
		return nil, connectionErrorf(true, err, "transport: %v", err)
	}
	// Adjust the connection flow control window if needed.
	if delta := uint32(initialConnWindowSize - defaultWindowSize); delta > 0 {
		if err := t.framer.writeWindowUpdate(true, 0, delta); err != nil {
			t.Close()
			return nil, connectionErrorf(true, err, "transport: %v", err)
		}
	}
	go t.controller()
	t.writableChan <- 0
	if stats.On() {
		t.ctx = stats.TagConn(t.ctx, &stats.ConnTagInfo{
			RemoteAddr: t.remoteAddr,
//.........這裏部分代碼省略.........