traefik/vendor/google.golang.org/grpc/stream.go

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/*
*
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* Copyright 2014 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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*
*/
package grpc
import (
"bytes"
"errors"
"io"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/trace"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
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"google.golang.org/grpc/peer"
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"google.golang.org/grpc/stats"
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"google.golang.org/grpc/status"
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"google.golang.org/grpc/transport"
)
// StreamHandler defines the handler called by gRPC server to complete the
// execution of a streaming RPC.
type StreamHandler func(srv interface{}, stream ServerStream) error
// StreamDesc represents a streaming RPC service's method specification.
type StreamDesc struct {
StreamName string
Handler StreamHandler
// At least one of these is true.
ServerStreams bool
ClientStreams bool
}
// Stream defines the common interface a client or server stream has to satisfy.
type Stream interface {
// Context returns the context for this stream.
Context() context.Context
// SendMsg blocks until it sends m, the stream is done or the stream
// breaks.
// On error, it aborts the stream and returns an RPC status on client
// side. On server side, it simply returns the error to the caller.
// SendMsg is called by generated code. Also Users can call SendMsg
// directly when it is really needed in their use cases.
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// It's safe to have a goroutine calling SendMsg and another goroutine calling
// recvMsg on the same stream at the same time.
// But it is not safe to call SendMsg on the same stream in different goroutines.
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SendMsg(m interface{}) error
// RecvMsg blocks until it receives a message or the stream is
// done. On client side, it returns io.EOF when the stream is done. On
// any other error, it aborts the stream and returns an RPC status. On
// server side, it simply returns the error to the caller.
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// It's safe to have a goroutine calling SendMsg and another goroutine calling
// recvMsg on the same stream at the same time.
// But it is not safe to call RecvMsg on the same stream in different goroutines.
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RecvMsg(m interface{}) error
}
// ClientStream defines the interface a client stream has to satisfy.
type ClientStream interface {
// Header returns the header metadata received from the server if there
// is any. It blocks if the metadata is not ready to read.
Header() (metadata.MD, error)
// Trailer returns the trailer metadata from the server, if there is any.
// It must only be called after stream.CloseAndRecv has returned, or
// stream.Recv has returned a non-nil error (including io.EOF).
Trailer() metadata.MD
// CloseSend closes the send direction of the stream. It closes the stream
// when non-nil error is met.
CloseSend() error
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// Stream.SendMsg() may return a non-nil error when something wrong happens sending
// the request. The returned error indicates the status of this sending, not the final
// status of the RPC.
// Always call Stream.RecvMsg() to get the final status if you care about the status of
// the RPC.
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Stream
}
// 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, err error) {
if cc.dopts.streamInt != nil {
return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
}
return newClientStream(ctx, desc, cc, method, opts...)
}
func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
var (
t transport.ClientTransport
s *transport.Stream
put func()
cancel context.CancelFunc
)
c := defaultCallInfo
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mc := cc.GetMethodConfig(method)
if mc.WaitForReady != nil {
c.failFast = !*mc.WaitForReady
}
if mc.Timeout != nil {
ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
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}
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opts = append(cc.dopts.callOptions, opts...)
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for _, o := range opts {
if err := o.before(&c); err != nil {
return nil, toRPCErr(err)
}
}
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c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
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callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
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// If it's not client streaming, we should already have the request to be sent,
// so we don't flush the header.
// If it's client streaming, the user may never send a request or send it any
// time soon, so we ask the transport to flush the header.
Flush: desc.ClientStreams,
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}
if cc.dopts.cp != nil {
callHdr.SendCompress = cc.dopts.cp.Type()
}
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if c.creds != nil {
callHdr.Creds = c.creds
}
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var trInfo traceInfo
if EnableTracing {
trInfo.tr = trace.New("grpc.Sent."+methodFamily(method), method)
trInfo.firstLine.client = true
if deadline, ok := ctx.Deadline(); ok {
trInfo.firstLine.deadline = deadline.Sub(time.Now())
}
trInfo.tr.LazyLog(&trInfo.firstLine, false)
ctx = trace.NewContext(ctx, trInfo.tr)
defer func() {
if err != nil {
// Need to call tr.finish() if error is returned.
// Because tr will not be returned to caller.
trInfo.tr.LazyPrintf("RPC: [%v]", err)
trInfo.tr.SetError()
trInfo.tr.Finish()
}
}()
}
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ctx = newContextWithRPCInfo(ctx)
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sh := cc.dopts.copts.StatsHandler
if sh != nil {
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ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
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begin := &stats.Begin{
Client: true,
BeginTime: time.Now(),
FailFast: c.failFast,
}
sh.HandleRPC(ctx, begin)
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defer func() {
if err != nil {
// Only handle end stats if err != nil.
end := &stats.End{
Client: true,
Error: err,
}
sh.HandleRPC(ctx, end)
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}
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}()
}
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gopts := BalancerGetOptions{
BlockingWait: !c.failFast,
}
for {
t, put, err = cc.getTransport(ctx, gopts)
if err != nil {
// TODO(zhaoq): Probably revisit the error handling.
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if _, ok := status.FromError(err); ok {
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return nil, err
}
if err == errConnClosing || err == errConnUnavailable {
if c.failFast {
return nil, Errorf(codes.Unavailable, "%v", err)
}
continue
}
// All the other errors are treated as Internal errors.
return nil, Errorf(codes.Internal, "%v", err)
}
s, err = t.NewStream(ctx, callHdr)
if err != nil {
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if _, ok := err.(transport.ConnectionError); ok && put != nil {
// If error is connection error, transport was sending data on wire,
// and we are not sure if anything has been sent on wire.
// If error is not connection error, we are sure nothing has been sent.
updateRPCInfoInContext(ctx, rpcInfo{bytesSent: true, bytesReceived: false})
}
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if put != nil {
put()
put = nil
}
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if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
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continue
}
return nil, toRPCErr(err)
}
break
}
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// Set callInfo.peer object from stream's context.
if peer, ok := peer.FromContext(s.Context()); ok {
c.peer = peer
}
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cs := &clientStream{
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opts: opts,
c: c,
desc: desc,
codec: cc.dopts.codec,
cp: cc.dopts.cp,
dc: cc.dopts.dc,
cancel: cancel,
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put: put,
t: t,
s: s,
p: &parser{r: s},
tracing: EnableTracing,
trInfo: trInfo,
statsCtx: ctx,
statsHandler: cc.dopts.copts.StatsHandler,
}
if cc.dopts.cp != nil {
cs.cbuf = new(bytes.Buffer)
}
// Listen on ctx.Done() to detect cancellation and s.Done() to detect normal termination
// when there is no pending I/O operations on this stream.
go func() {
select {
case <-t.Error():
// Incur transport error, simply exit.
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case <-cc.ctx.Done():
cs.finish(ErrClientConnClosing)
cs.closeTransportStream(ErrClientConnClosing)
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case <-s.Done():
// TODO: The trace of the RPC is terminated here when there is no pending
// I/O, which is probably not the optimal solution.
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cs.finish(s.Status().Err())
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cs.closeTransportStream(nil)
case <-s.GoAway():
cs.finish(errConnDrain)
cs.closeTransportStream(errConnDrain)
case <-s.Context().Done():
err := s.Context().Err()
cs.finish(err)
cs.closeTransportStream(transport.ContextErr(err))
}
}()
return cs, nil
}
// clientStream implements a client side Stream.
type clientStream struct {
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opts []CallOption
c callInfo
t transport.ClientTransport
s *transport.Stream
p *parser
desc *StreamDesc
codec Codec
cp Compressor
cbuf *bytes.Buffer
dc Decompressor
cancel context.CancelFunc
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tracing bool // set to EnableTracing when the clientStream is created.
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mu sync.Mutex
put func()
closed bool
finished bool
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// trInfo.tr is set when the clientStream is created (if EnableTracing is true),
// and is set to nil when the clientStream's finish method is called.
trInfo traceInfo
// statsCtx keeps the user context for stats handling.
// All stats collection should use the statsCtx (instead of the stream context)
// so that all the generated stats for a particular RPC can be associated in the processing phase.
statsCtx context.Context
statsHandler stats.Handler
}
func (cs *clientStream) Context() context.Context {
return cs.s.Context()
}
func (cs *clientStream) Header() (metadata.MD, error) {
m, err := cs.s.Header()
if err != nil {
if _, ok := err.(transport.ConnectionError); !ok {
cs.closeTransportStream(err)
}
}
return m, err
}
func (cs *clientStream) Trailer() metadata.MD {
return cs.s.Trailer()
}
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 cs.statsHandler != nil {
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 {
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return err
}
if cs.c.maxSendMessageSize == nil {
return Errorf(codes.Internal, "callInfo maxSendMessageSize field uninitialized(nil)")
}
if len(out) > *cs.c.maxSendMessageSize {
return Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(out), *cs.c.maxSendMessageSize)
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}
err = cs.t.Write(cs.s, out, &transport.Options{Last: false})
if err == nil && outPayload != nil {
outPayload.SentTime = time.Now()
cs.statsHandler.HandleRPC(cs.statsCtx, outPayload)
}
return err
}
func (cs *clientStream) RecvMsg(m interface{}) (err error) {
var inPayload *stats.InPayload
if cs.statsHandler != nil {
inPayload = &stats.InPayload{
Client: true,
}
}
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if cs.c.maxReceiveMessageSize == nil {
return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
}
err = recv(cs.p, cs.codec, cs.s, cs.dc, m, *cs.c.maxReceiveMessageSize, inPayload)
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defer func() {
// err != nil indicates the termination of the stream.
if err != nil {
cs.finish(err)
}
}()
if err == nil {
if cs.tracing {
cs.mu.Lock()
if cs.trInfo.tr != nil {
cs.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
}
cs.mu.Unlock()
}
if inPayload != nil {
cs.statsHandler.HandleRPC(cs.statsCtx, inPayload)
}
if !cs.desc.ClientStreams || cs.desc.ServerStreams {
return
}
// Special handling for client streaming rpc.
// This recv expects EOF or errors, so we don't collect inPayload.
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if cs.c.maxReceiveMessageSize == nil {
return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
}
err = recv(cs.p, cs.codec, cs.s, cs.dc, m, *cs.c.maxReceiveMessageSize, nil)
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cs.closeTransportStream(err)
if err == nil {
return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
}
if err == io.EOF {
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if se := cs.s.Status().Err(); se != nil {
return se
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}
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cs.finish(err)
return nil
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}
return toRPCErr(err)
}
if _, ok := err.(transport.ConnectionError); !ok {
cs.closeTransportStream(err)
}
if err == io.EOF {
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if statusErr := cs.s.Status().Err(); statusErr != nil {
return statusErr
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}
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// Returns io.EOF to indicate the end of the stream.
return
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}
return toRPCErr(err)
}
func (cs *clientStream) CloseSend() (err error) {
err = cs.t.Write(cs.s, nil, &transport.Options{Last: true})
defer func() {
if err != nil {
cs.finish(err)
}
}()
if err == nil || err == io.EOF {
return nil
}
if _, ok := err.(transport.ConnectionError); !ok {
cs.closeTransportStream(err)
}
err = toRPCErr(err)
return
}
func (cs *clientStream) closeTransportStream(err error) {
cs.mu.Lock()
if cs.closed {
cs.mu.Unlock()
return
}
cs.closed = true
cs.mu.Unlock()
cs.t.CloseStream(cs.s, err)
}
func (cs *clientStream) finish(err error) {
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cs.mu.Lock()
defer cs.mu.Unlock()
if cs.finished {
return
}
cs.finished = true
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defer func() {
if cs.cancel != nil {
cs.cancel()
}
}()
for _, o := range cs.opts {
o.after(&cs.c)
}
if cs.put != nil {
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updateRPCInfoInContext(cs.s.Context(), rpcInfo{
bytesSent: cs.s.BytesSent(),
bytesReceived: cs.s.BytesReceived(),
})
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cs.put()
cs.put = nil
}
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if cs.statsHandler != nil {
end := &stats.End{
Client: true,
EndTime: time.Now(),
}
if err != io.EOF {
// end.Error is nil if the RPC finished successfully.
end.Error = toRPCErr(err)
}
cs.statsHandler.HandleRPC(cs.statsCtx, end)
}
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if !cs.tracing {
return
}
if cs.trInfo.tr != nil {
if err == nil || err == io.EOF {
cs.trInfo.tr.LazyPrintf("RPC: [OK]")
} else {
cs.trInfo.tr.LazyPrintf("RPC: [%v]", err)
cs.trInfo.tr.SetError()
}
cs.trInfo.tr.Finish()
cs.trInfo.tr = nil
}
}
// ServerStream defines the interface a server stream has to satisfy.
type ServerStream interface {
// SetHeader sets the header metadata. It may be called multiple times.
// When call multiple times, all the provided metadata will be merged.
// All the metadata will be sent out when one of the following happens:
// - ServerStream.SendHeader() is called;
// - The first response is sent out;
// - An RPC status is sent out (error or success).
SetHeader(metadata.MD) error
// SendHeader sends the header metadata.
// The provided md and headers set by SetHeader() will be sent.
// It fails if called multiple times.
SendHeader(metadata.MD) error
// SetTrailer sets the trailer metadata which will be sent with the RPC status.
// When called more than once, all the provided metadata will be merged.
SetTrailer(metadata.MD)
Stream
}
// serverStream implements a server side Stream.
type serverStream struct {
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t transport.ServerTransport
s *transport.Stream
p *parser
codec Codec
cp Compressor
dc Decompressor
cbuf *bytes.Buffer
maxReceiveMessageSize int
maxSendMessageSize int
trInfo *traceInfo
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statsHandler stats.Handler
mu sync.Mutex // protects trInfo.tr after the service handler runs.
}
func (ss *serverStream) Context() context.Context {
return ss.s.Context()
}
func (ss *serverStream) SetHeader(md metadata.MD) error {
if md.Len() == 0 {
return nil
}
return ss.s.SetHeader(md)
}
func (ss *serverStream) SendHeader(md metadata.MD) error {
return ss.t.WriteHeader(ss.s, md)
}
func (ss *serverStream) SetTrailer(md metadata.MD) {
if md.Len() == 0 {
return
}
ss.s.SetTrailer(md)
return
}
func (ss *serverStream) SendMsg(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: true, msg: m}, true)
} else {
ss.trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
ss.trInfo.tr.SetError()
}
}
ss.mu.Unlock()
}
}()
var outPayload *stats.OutPayload
if ss.statsHandler != nil {
outPayload = &stats.OutPayload{}
}
out, err := encode(ss.codec, m, ss.cp, ss.cbuf, outPayload)
defer func() {
if ss.cbuf != nil {
ss.cbuf.Reset()
}
}()
if err != nil {
return err
}
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if len(out) > ss.maxSendMessageSize {
return Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(out), ss.maxSendMessageSize)
}
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if err := ss.t.Write(ss.s, out, &transport.Options{Last: false}); err != nil {
return toRPCErr(err)
}
if outPayload != nil {
outPayload.SentTime = time.Now()
ss.statsHandler.HandleRPC(ss.s.Context(), outPayload)
}
return nil
}
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 ss.statsHandler != nil {
inPayload = &stats.InPayload{}
}
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if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, inPayload); err != nil {
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if err == io.EOF {
return err
}
if err == io.ErrUnexpectedEOF {
err = Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
}
return toRPCErr(err)
}
if inPayload != nil {
ss.statsHandler.HandleRPC(ss.s.Context(), inPayload)
}
return nil
}