// 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 {
data, err := c.GetRequestMetadata(ctx)
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
t.mu.Unlock()
// 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
}
// 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 *http2Server) operateHeaders(hDec *hpackDecoder, s *Stream, frame headerFrame, endStream bool, handle func(*Stream), wg *sync.WaitGroup) (pendingStream *Stream) {
defer func() {
if pendingStream == nil {
hDec.state = decodeState{}
}
}()
endHeaders, err := hDec.decodeServerHTTP2Headers(frame)
if s == nil {
// s has been closed.
return nil
}
if err != nil {
grpclog.Printf("transport: http2Server.operateHeader found %v", err)
if se, ok := err.(StreamError); ok {
t.controlBuf.put(&resetStream{s.id, statusCodeConvTab[se.Code]})
}
return nil
}
if endStream {
// s is just created by the caller. No lock needed.
s.state = streamReadDone
}
if !endHeaders {
return s
}
t.mu.Lock()
if t.state != reachable {
t.mu.Unlock()
return nil
}
if uint32(len(t.activeStreams)) >= t.maxStreams {
t.mu.Unlock()
t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
return nil
}
s.sendQuotaPool = newQuotaPool(int(t.streamSendQuota))
t.activeStreams[s.id] = s
t.mu.Unlock()
s.windowHandler = func(n int) {
t.updateWindow(s, uint32(n))
}
if hDec.state.timeoutSet {
s.ctx, s.cancel = context.WithTimeout(context.TODO(), hDec.state.timeout)
} else {
s.ctx, s.cancel = context.WithCancel(context.TODO())
}
// Attach Auth info if there is any.
if t.authInfo != nil {
s.ctx = credentials.NewContext(s.ctx, t.authInfo)
}
// 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(hDec.state.mdata) > 0 {
s.ctx = metadata.NewContext(s.ctx, hDec.state.mdata)
}
s.dec = &recvBufferReader{
ctx: s.ctx,
recv: s.buf,
}
s.method = hDec.state.method
wg.Add(1)
go func() {
handle(s)
wg.Done()
}()
return nil
}