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/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
package transport
import (
"bytes"
"errors"
"io"
"math"
"net"
"strings"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/http2"
"golang.org/x/net/http2/hpack"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/metadata"
)
// http2Client implements the ClientTransport interface with HTTP2.
type http2Client struct {
target string // server name/addr
userAgent string
conn net.Conn // underlying communication channel
authInfo credentials.AuthInfo // auth info about the connection
nextID uint32 // the next stream ID to be used
// writableChan synchronizes write access to the transport.
// A writer acquires the write lock by sending a value on writableChan
// and releases it by receiving from writableChan.
writableChan chan int
// shutdownChan is closed when Close is called.
// Blocking operations should select on shutdownChan to avoid
// blocking forever after Close.
// TODO(zhaoq): Maybe have a channel context?
shutdownChan chan struct{}
// errorChan is closed to notify the I/O error to the caller.
errorChan chan struct{}
framer *framer
hBuf *bytes.Buffer // the buffer for HPACK encoding
hEnc *hpack.Encoder // HPACK encoder
// controlBuf delivers all the control related tasks (e.g., window
// updates, reset streams, and various settings) to the controller.
controlBuf *recvBuffer
fc *inFlow
// sendQuotaPool provides flow control to outbound message.
sendQuotaPool *quotaPool
// streamsQuota limits the max number of concurrent streams.
streamsQuota *quotaPool
// The scheme used: https if TLS is on, http otherwise.
scheme string
authCreds []credentials.Credentials
mu sync.Mutex // guard the following variables
state transportState // the state of underlying connection
activeStreams map[uint32]*Stream
// The max number of concurrent streams
maxStreams int
// the per-stream outbound flow control window size set by the peer.
streamSendQuota uint32
}
// 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(addr string, opts *ConnectOptions) (_ ClientTransport, err error) {
if opts.Dialer == nil {
// Set the default Dialer.
opts.Dialer = func(addr string, timeout time.Duration) (net.Conn, error) {
return net.DialTimeout("tcp", addr, timeout)
}
}
scheme := "http"
startT := time.Now()
timeout := opts.Timeout
conn, connErr := opts.Dialer(addr, timeout)
if connErr != nil {
return nil, ConnectionErrorf("transport: %v", connErr)
}
var authInfo credentials.AuthInfo
for _, c := range opts.AuthOptions {
if ccreds, ok := c.(credentials.TransportAuthenticator); ok {
scheme = "https"
// TODO(zhaoq): Now the first TransportAuthenticator is used if there are
// multiple ones provided. Revisit this if it is not appropriate. Probably
// place the ClientTransport construction into a separate function to make
// things clear.
if timeout > 0 {
timeout -= time.Since(startT)
}
conn, authInfo, connErr = ccreds.ClientHandshake(addr, conn, timeout)
break
}
}
if connErr != nil {
return nil, ConnectionErrorf("transport: %v", connErr)
}
defer func() {
if err != nil {
conn.Close()
}
}()
// Send connection preface to server.
n, err := conn.Write(clientPreface)
if err != nil {
return nil, ConnectionErrorf("transport: %v", err)
}
if n != len(clientPreface) {
return nil, ConnectionErrorf("transport: preface mismatch, wrote %d bytes; want %d", n, len(clientPreface))
}
framer := newFramer(conn)
if initialWindowSize != defaultWindowSize {
err = framer.writeSettings(true, http2.Setting{http2.SettingInitialWindowSize, uint32(initialWindowSize)})
} else {
err = framer.writeSettings(true)
}
if err != nil {
return nil, ConnectionErrorf("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("transport: %v", err)
}
}
ua := primaryUA
if opts.UserAgent != "" {
ua = opts.UserAgent + " " + ua
}
var buf bytes.Buffer
t := &http2Client{
target: addr,
userAgent: ua,
conn: conn,
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{}),
framer: framer,
hBuf: &buf,
hEnc: hpack.NewEncoder(&buf),
controlBuf: newRecvBuffer(),
fc: &inFlow{limit: initialConnWindowSize},
sendQuotaPool: newQuotaPool(defaultWindowSize),
scheme: scheme,
state: reachable,
activeStreams: make(map[uint32]*Stream),
authCreds: opts.AuthOptions,
maxStreams: math.MaxInt32,
streamSendQuota: defaultWindowSize,
}
go t.controller()
t.writableChan <- 0
// Start the reader goroutine for incoming message. The threading model
// on receiving is that 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()
return t, nil
}
func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
fc := &inFlow{
limit: initialWindowSize,
conn: t.fc,
}
// TODO(zhaoq): Handle uint32 overflow of Stream.id.
s := &Stream{
id: t.nextID,
method: callHdr.Method,
buf: newRecvBuffer(),
fc: fc,
sendQuotaPool: newQuotaPool(int(t.streamSendQuota)),
headerChan: make(chan struct{}),
}
t.nextID += 2
s.windowHandler = func(n int) {
t.updateWindow(s, uint32(n))
}
// Make a stream be able to cancel the pending operations by itself.
s.ctx, s.cancel = context.WithCancel(ctx)
s.dec = &recvBufferReader{
ctx: s.ctx,
recv: s.buf,
}
return s
}
// NewStream creates a stream and register it into the transport as "active"
// streams.
func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
// Record the timeout value on the context.
var timeout time.Duration
if dl, ok := ctx.Deadline(); ok {
timeout = dl.Sub(time.Now())
if timeout <= 0 {
return nil, ContextErr(context.DeadlineExceeded)
}
}
// Attach Auth info if there is any.
if t.authInfo != nil {
ctx = credentials.NewContext(ctx, t.authInfo)
}
authData := make(map[string]string)
for _, c := range t.authCreds {
// Construct URI required to get auth request metadata.
var port string
if pos := strings.LastIndex(t.target, ":"); pos != -1 {
// Omit port if it is the default one.
if t.target[pos+1:] != "443" {
port = ":" + t.target[pos+1:]
}
}
pos := strings.LastIndex(callHdr.Method, "/")
if pos == -1 {
return nil, StreamErrorf(codes.InvalidArgument, "transport: malformed method name: %q", callHdr.Method)
}
audience := "https://" + callHdr.Host + port + callHdr.Method[:pos]
data, err := c.GetRequestMetadata(ctx, audience)
if err != nil {
return nil, StreamErrorf(codes.InvalidArgument, "transport: %v", err)
}
for k, v := range data {
authData[k] = v
}
}
t.mu.Lock()
if t.state != reachable {
t.mu.Unlock()
return nil, ErrConnClosing
}
checkStreamsQuota := t.streamsQuota != nil
t.mu.Unlock()
if checkStreamsQuota {
sq, err := wait(ctx, t.shutdownChan, t.streamsQuota.acquire())
if err != nil {
return nil, err
}
// Returns the quota balance back.
if sq > 1 {
t.streamsQuota.add(sq - 1)
}
}
if _, err := wait(ctx, t.shutdownChan, t.writableChan); err != nil {
// t.streamsQuota will be updated when t.CloseStream is invoked.
return nil, err
}
t.mu.Lock()
if t.state != reachable {
t.mu.Unlock()
return nil, ErrConnClosing
}
s := t.newStream(ctx, callHdr)
t.activeStreams[s.id] = s
// This stream is not counted when applySetings(...) initialize t.streamsQuota.
// Reset t.streamsQuota to the right value.
var reset bool
if !checkStreamsQuota && t.streamsQuota != nil {
reset = true
}
t.mu.Unlock()
if reset {
t.streamsQuota.reset(-1)
}
// HPACK encodes various headers. Note that once WriteField(...) is
// called, the corresponding headers/continuation frame has to be sent
// because hpack.Encoder is stateful.
t.hBuf.Reset()
t.hEnc.WriteField(hpack.HeaderField{Name: ":method", Value: "POST"})
t.hEnc.WriteField(hpack.HeaderField{Name: ":scheme", Value: t.scheme})
t.hEnc.WriteField(hpack.HeaderField{Name: ":path", Value: callHdr.Method})
t.hEnc.WriteField(hpack.HeaderField{Name: ":authority", Value: callHdr.Host})
t.hEnc.WriteField(hpack.HeaderField{Name: "content-type", Value: "application/grpc"})
t.hEnc.WriteField(hpack.HeaderField{Name: "user-agent", Value: t.userAgent})
t.hEnc.WriteField(hpack.HeaderField{Name: "te", Value: "trailers"})
if timeout > 0 {
t.hEnc.WriteField(hpack.HeaderField{Name: "grpc-timeout", Value: timeoutEncode(timeout)})
}
for k, v := range authData {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: v})
}
var (
hasMD bool
endHeaders bool
)
if md, ok := metadata.FromContext(ctx); ok {
hasMD = true
for k, v := range md {
for _, entry := range v {
t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
}
}
}
first := true
// Sends the headers in a single batch even when they span multiple frames.
for !endHeaders {
size := t.hBuf.Len()
if size > http2MaxFrameLen {
size = http2MaxFrameLen
} else {
endHeaders = true
}
if first {
// Sends a HeadersFrame to server to start a new stream.
p := http2.HeadersFrameParam{
StreamID: s.id,
BlockFragment: t.hBuf.Next(size),
EndStream: false,
EndHeaders: endHeaders,
}
// Do a force flush for the buffered frames iff it is the last headers frame
// and there is header metadata to be sent. Otherwise, there is flushing until
// the corresponding data frame is written.
err = t.framer.writeHeaders(hasMD && endHeaders, p)
first = false
} else {
// Sends Continuation frames for the leftover headers.
err = t.framer.writeContinuation(hasMD && endHeaders, s.id, endHeaders, t.hBuf.Next(size))
}
if err != nil {
t.notifyError(err)
return nil, ConnectionErrorf("transport: %v", err)
}
}
t.writableChan <- 0
return s, nil
}
// CloseStream clears the footprint of a stream when the stream is not needed any more.
// This must not be executed in reader's goroutine.
func (t *http2Client) CloseStream(s *Stream, err error) {
var updateStreams bool
t.mu.Lock()
if t.streamsQuota != nil {
updateStreams = true
}
delete(t.activeStreams, s.id)
t.mu.Unlock()
if updateStreams {
t.streamsQuota.add(1)
}
// In case stream sending and receiving are invoked in separate
// goroutines (e.g., bi-directional streaming), the caller needs
// to call cancel on the stream to interrupt the blocking on
// other goroutines.
s.cancel()
s.mu.Lock()
if q := s.fc.restoreConn(); q > 0 {
t.controlBuf.put(&windowUpdate{0, q})
}
if s.state == streamDone {
s.mu.Unlock()
return
}
if !s.headerDone {
close(s.headerChan)
s.headerDone = true
}
s.state = streamDone
s.mu.Unlock()
if _, ok := err.(StreamError); ok {
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeCancel})
}
}
// 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 errors.New("transport: Close() was already called")
}
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})
}
return
}
// Write formats the data into HTTP2 data frame(s) and sends it out. The caller
// should proceed only if Write returns nil.
// TODO(zhaoq): opts.Delay is ignored in this implementation. Support it later
// if it improves the performance.
func (t *http2Client) Write(s *Stream, data []byte, opts *Options) error {
r := bytes.NewBuffer(data)
for {
var p []byte
if r.Len() > 0 {
size := http2MaxFrameLen
s.sendQuotaPool.add(0)
// Wait until the stream has some quota to send the data.
sq, err := wait(s.ctx, t.shutdownChan, s.sendQuotaPool.acquire())
if err != nil {
return err
}
t.sendQuotaPool.add(0)
// Wait until the transport has some quota to send the data.
tq, err := wait(s.ctx, t.shutdownChan, t.sendQuotaPool.acquire())
if err != nil {
if _, ok := err.(StreamError); ok {
t.sendQuotaPool.cancel()
}
return err
}
if sq < size {
size = sq
}
if tq < size {
size = tq
}
p = r.Next(size)
ps := len(p)
if ps < sq {
// Overbooked stream quota. Return it back.
s.sendQuotaPool.add(sq - ps)
}
if ps < tq {
// Overbooked transport quota. Return it back.
t.sendQuotaPool.add(tq - ps)
}
}
var (
endStream bool
forceFlush bool
)
if opts.Last && r.Len() == 0 {
endStream = true
}
// Indicate there is a writer who is about to write a data frame.
t.framer.adjustNumWriters(1)
// Got some quota. Try to acquire writing privilege on the transport.
if _, err := wait(s.ctx, t.shutdownChan, t.writableChan); err != nil {
if t.framer.adjustNumWriters(-1) == 0 {
// This writer is the last one in this batch and has the
// responsibility to flush the buffered frames. It queues
// a flush request to controlBuf instead of flushing directly
// in order to avoid the race with other writing or flushing.
t.controlBuf.put(&flushIO{})
}
return err
}
if r.Len() == 0 && t.framer.adjustNumWriters(0) == 1 {
// Do a force flush iff this is last frame for the entire gRPC message
// and the caller is the only writer at this moment.
forceFlush = true
}
// If WriteData fails, all the pending streams will be handled
// by http2Client.Close(). No explicit CloseStream() needs to be
// invoked.
if err := t.framer.writeData(forceFlush, s.id, endStream, p); err != nil {
t.notifyError(err)
return ConnectionErrorf("transport: %v", err)
}
if t.framer.adjustNumWriters(-1) == 0 {
t.framer.flushWrite()
}
t.writableChan <- 0
if r.Len() == 0 {
break
}
}
if !opts.Last {
return nil
}
s.mu.Lock()
if s.state != streamDone {
if s.state == streamReadDone {
s.state = streamDone
} else {
s.state = streamWriteDone
}
}
s.mu.Unlock()
return nil
}
func (t *http2Client) getStream(f http2.Frame) (*Stream, bool) {
t.mu.Lock()
defer t.mu.Unlock()
if t.activeStreams == nil {
// The transport is closing.
return nil, false
}
if s, ok := t.activeStreams[f.Header().StreamID]; ok {
return s, true
}
return nil, false
}
// updateWindow adjusts the inbound quota for the stream and the transport.
// Window updates will deliver to the controller for sending when
// the cumulative quota exceeds the corresponding threshold.
func (t *http2Client) updateWindow(s *Stream, n uint32) {
swu, cwu := s.fc.onRead(n)
if swu > 0 {
t.controlBuf.put(&windowUpdate{s.id, swu})
}
if cwu > 0 {
t.controlBuf.put(&windowUpdate{0, cwu})
}
}
func (t *http2Client) handleData(f *http2.DataFrame) {
// Select the right stream to dispatch.
s, ok := t.getStream(f)
if !ok {
return
}
size := len(f.Data())
if size > 0 {
if err := s.fc.onData(uint32(size)); err != nil {
if _, ok := err.(ConnectionError); ok {
t.notifyError(err)
return
}
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return
}
s.state = streamDone
s.statusCode = codes.Internal
s.statusDesc = err.Error()
s.mu.Unlock()
s.write(recvMsg{err: io.EOF})
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeFlowControl})
return
}
// TODO(bradfitz, zhaoq): A copy is required here because there is no
// guarantee f.Data() is consumed before the arrival of next frame.
// Can this copy be eliminated?
data := make([]byte, size)
copy(data, f.Data())
s.write(recvMsg{data: data})
}
// The server has closed the stream without sending trailers. Record that
// the read direction is closed, and set the status appropriately.
if f.FrameHeader.Flags.Has(http2.FlagDataEndStream) {
s.mu.Lock()
if s.state == streamWriteDone {
s.state = streamDone
} else {
s.state = streamReadDone
}
s.statusCode = codes.Internal
s.statusDesc = "server closed the stream without sending trailers"
s.mu.Unlock()
s.write(recvMsg{err: io.EOF})
}
}
func (t *http2Client) handleRSTStream(f *http2.RSTStreamFrame) {
s, ok := t.getStream(f)
if !ok {
return
}
s.mu.Lock()
if s.state == streamDone {
s.mu.Unlock()
return
}
s.state = streamDone
if !s.headerDone {
close(s.headerChan)
s.headerDone = true
}
s.statusCode, ok = http2RSTErrConvTab[http2.ErrCode(f.ErrCode)]
if !ok {
grpclog.Println("transport: http2Client.handleRSTStream found no mapped gRPC status for the received http2 error ", f.ErrCode)
}
s.mu.Unlock()
s.write(recvMsg{err: io.EOF})
}
func (t *http2Client) handleSettings(f *http2.SettingsFrame) {
if f.IsAck() {
return
}
var ss []http2.Setting
f.ForeachSetting(func(s http2.Setting) error {
ss = append(ss, s)
return nil
})
// The settings will be applied once the ack is sent.
t.controlBuf.put(&settings{ack: true, ss: ss})
}
func (t *http2Client) handlePing(f *http2.PingFrame) {
pingAck := &ping{ack: true}
copy(pingAck.data[:], f.Data[:])
t.controlBuf.put(pingAck)
}
func (t *http2Client) handleGoAway(f *http2.GoAwayFrame) {
// TODO(zhaoq): GoAwayFrame handler to be implemented
}
func (t *http2Client) handleWindowUpdate(f *http2.WindowUpdateFrame) {
id := f.Header().StreamID
incr := f.Increment
if id == 0 {
t.sendQuotaPool.add(int(incr))
return
}
if s, ok := t.getStream(f); ok {
s.sendQuotaPool.add(int(incr))
}
}
// operateHeader takes action on the decoded headers. It returns the current
// stream if there are remaining headers on the wire (in the following
// Continuation frame).
func (t *http2Client) operateHeaders(hDec *hpackDecoder, s *Stream, frame headerFrame, endStream bool) (pendingStream *Stream) {
defer func() {
if pendingStream == nil {
hDec.state = decodeState{}
}
}()
endHeaders, err := hDec.decodeClientHTTP2Headers(frame)
if s == nil {
// s has been closed.
return nil
}
if err != nil {
s.write(recvMsg{err: err})
// Something wrong. Stops reading even when there is remaining.
return nil
}
if !endHeaders {
return s
}
s.mu.Lock()
if !s.headerDone {
if !endStream && len(hDec.state.mdata) > 0 {
s.header = hDec.state.mdata
}
close(s.headerChan)
s.headerDone = true
}
if !endStream || s.state == streamDone {
s.mu.Unlock()
return nil
}
if len(hDec.state.mdata) > 0 {
s.trailer = hDec.state.mdata
}
s.state = streamDone
s.statusCode = hDec.state.statusCode
s.statusDesc = hDec.state.statusDesc
s.mu.Unlock()
s.write(recvMsg{err: io.EOF})
return nil
}
// reader runs as a separate goroutine in charge of reading data from network
// connection.
//
// TODO(zhaoq): currently one reader per transport. Investigate whether this is
// optimal.
// TODO(zhaoq): Check the validity of the incoming frame sequence.
func (t *http2Client) reader() {
// Check the validity of server preface.
frame, err := t.framer.readFrame()
if err != nil {
t.notifyError(err)
return
}
sf, ok := frame.(*http2.SettingsFrame)
if !ok {
t.notifyError(err)
return
}
t.handleSettings(sf)
hDec := newHPACKDecoder()
var curStream *Stream
// loop to keep reading incoming messages on this transport.
for {
frame, err := t.framer.readFrame()
if err != nil {
t.notifyError(err)
return
}
switch frame := frame.(type) {
case *http2.HeadersFrame:
// operateHeaders has to be invoked regardless the value of curStream
// because the HPACK decoder needs to be updated using the received
// headers.
curStream, _ = t.getStream(frame)
endStream := frame.Header().Flags.Has(http2.FlagHeadersEndStream)
curStream = t.operateHeaders(hDec, curStream, frame, endStream)
case *http2.ContinuationFrame:
curStream = t.operateHeaders(hDec, curStream, frame, frame.HeadersEnded())
case *http2.DataFrame:
t.handleData(frame)
case *http2.RSTStreamFrame:
t.handleRSTStream(frame)
case *http2.SettingsFrame:
t.handleSettings(frame)
case *http2.PingFrame:
t.handlePing(frame)
case *http2.GoAwayFrame:
t.handleGoAway(frame)
case *http2.WindowUpdateFrame:
t.handleWindowUpdate(frame)
default:
grpclog.Printf("transport: http2Client.reader got unhandled frame type %v.", frame)
}
}
}
func (t *http2Client) applySettings(ss []http2.Setting) {
for _, s := range ss {
switch s.ID {
case http2.SettingMaxConcurrentStreams:
// TODO(zhaoq): This is a hack to avoid significant refactoring of the
// code to deal with the unrealistic int32 overflow. Probably will try
// to find a better way to handle this later.
if s.Val > math.MaxInt32 {
s.Val = math.MaxInt32
}
t.mu.Lock()
reset := t.streamsQuota != nil
if !reset {
t.streamsQuota = newQuotaPool(int(s.Val) - len(t.activeStreams))
}
ms := t.maxStreams
t.maxStreams = int(s.Val)
t.mu.Unlock()
if reset {
t.streamsQuota.reset(int(s.Val) - ms)
}
case http2.SettingInitialWindowSize:
t.mu.Lock()
for _, stream := range t.activeStreams {
// Adjust the sending quota for each stream.
stream.sendQuotaPool.reset(int(s.Val - t.streamSendQuota))
}
t.streamSendQuota = s.Val
t.mu.Unlock()
}
}
}
// controller running in a separate goroutine takes charge of sending control
// frames (e.g., window update, reset stream, setting, etc.) to the server.
func (t *http2Client) controller() {
for {
select {
case i := <-t.controlBuf.get():
t.controlBuf.load()
select {
case <-t.writableChan:
switch i := i.(type) {
case *windowUpdate:
t.framer.writeWindowUpdate(true, i.streamID, i.increment)
case *settings:
if i.ack {
t.framer.writeSettingsAck(true)
t.applySettings(i.ss)
} else {
t.framer.writeSettings(true, i.ss...)
}
case *resetStream:
t.framer.writeRSTStream(true, i.streamID, i.code)
case *flushIO:
t.framer.flushWrite()
case *ping:
t.framer.writePing(true, i.ack, i.data)
default:
grpclog.Printf("transport: http2Client.controller got unexpected item type %v\n", i)
}
t.writableChan <- 0
continue
case <-t.shutdownChan:
return
}
case <-t.shutdownChan:
return
}
}
}
func (t *http2Client) Error() <-chan struct{} {
return t.errorChan
}
func (t *http2Client) notifyError(err error) {
t.mu.Lock()
defer t.mu.Unlock()
// make sure t.errorChan is closed only once.
if t.state == reachable {
t.state = unreachable
close(t.errorChan)
grpclog.Printf("transport: http2Client.notifyError got notified that the client transport was broken %v.", err)
}
}