// NewClientStream creates a new Stream for the client side. This is called
// by generated code.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
var (
t transport.ClientTransport
err error
)
t, err = cc.dopts.picker.Pick(ctx)
if err != nil {
return nil, toRPCErr(err)
}
// TODO(zhaoq): CallOption is omitted. Add support when it is needed.
callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
}
cs := &clientStream{
desc: desc,
codec: cc.dopts.codec,
tracing: EnableTracing,
}
if cs.tracing {
cs.trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
cs.trInfo.firstLine.client = true
if deadline, ok := ctx.Deadline(); ok {
cs.trInfo.firstLine.deadline = deadline.Sub(time.Now())
}
cs.trInfo.tr.LazyLog(&cs.trInfo.firstLine, false)
ctx = trace.NewContext(ctx, cs.trInfo.tr)
}
s, err := t.NewStream(ctx, callHdr)
if err != nil {
return nil, toRPCErr(err)
}
cs.t = t
cs.s = s
cs.p = &parser{s: s}
// Listen on ctx.Done() to detect cancellation when there is no pending
// I/O operations on this stream.
go func() {
<-s.Context().Done()
cs.closeTransportStream(transport.ContextErr(s.Context().Err()))
}()
return cs, nil
}
// Invoke is called by the generated code. It sends the RPC request on the
// wire and returns after response is received.
func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (err error) {
var c callInfo
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 err != nil {
c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
c.traceInfo.tr.SetError()
}
}()
}
topts := &transport.Options{
Last: true,
Delay: false,
}
var (
lastErr error // record the error that happened
)
for {
var (
err error
t transport.ClientTransport
stream *transport.Stream
)
// TODO(zhaoq): Need a formal spec of retry strategy for non-failfast rpcs.
if lastErr != nil && c.failFast {
return toRPCErr(lastErr)
}
callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
}
t, err = cc.dopts.picker.Pick(ctx)
if err != nil {
if lastErr != nil {
// This was a retry; return the error from the last attempt.
return toRPCErr(lastErr)
}
return toRPCErr(err)
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
}
stream, err = sendRequest(ctx, cc.dopts.codec, callHdr, t, args, topts)
if err != nil {
if _, ok := err.(transport.ConnectionError); ok {
lastErr = err
continue
}
if lastErr != nil {
return toRPCErr(lastErr)
}
return toRPCErr(err)
}
// Receive the response
lastErr = recvResponse(cc.dopts.codec, t, &c, stream, reply)
if _, ok := lastErr.(transport.ConnectionError); ok {
continue
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
}
t.CloseStream(stream, lastErr)
if lastErr != nil {
return toRPCErr(lastErr)
}
return Errorf(stream.StatusCode(), stream.StatusDesc())
}
}
// 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
}