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/*
*
* Copyright 2014 gRPC authors.
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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.
*
*/
package grpc
import (
"context"
"errors"
"io"
"math"
"strconv"
"sync"
"time"
"golang.org/x/net/trace"
"google.golang.org/grpc/balancer"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/connectivity"
"google.golang.org/grpc/encoding"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/internal/binarylog"
"google.golang.org/grpc/internal/channelz"
"google.golang.org/grpc/internal/grpcrand"
"google.golang.org/grpc/internal/transport"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/stats"
"google.golang.org/grpc/status"
)
// StreamHandler defines the handler called by gRPC server to complete the
// execution of a streaming RPC. If a StreamHandler returns an error, it
// should be produced by the status package, or else gRPC will use
// codes.Unknown as the status code and err.Error() as the status message
// of the 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.
//
// Deprecated: See ClientStream and ServerStream documentation instead.
type Stream interface {
// Deprecated: See ClientStream and ServerStream documentation instead.
Context() context.Context
// Deprecated: See ClientStream and ServerStream documentation instead.
SendMsg(m interface{}) error
// Deprecated: See ClientStream and ServerStream documentation instead.
RecvMsg(m interface{}) error
}
// ClientStream defines the client-side behavior of a streaming RPC.
//
// All errors returned from ClientStream methods are compatible with the
// status package.
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. It is also not safe to call CloseSend
// concurrently with SendMsg.
CloseSend() error
// Context returns the context for this stream.
//
// It should not be called until after Header or RecvMsg has returned. Once
// called, subsequent client-side retries are disabled.
Context() context.Context
// SendMsg is generally called by generated code. On error, SendMsg aborts
// the stream. If the error was generated by the client, the status is
// returned directly; otherwise, io.EOF is returned and the status of
// the stream may be discovered using RecvMsg.
//
// SendMsg blocks until:
// - There is sufficient flow control to schedule m with the transport, or
// - The stream is done, or
// - The stream breaks.
//
// SendMsg does not wait until the message is received by the server. An
// untimely stream closure may result in lost messages. To ensure delivery,
// users should ensure the RPC completed successfully using RecvMsg.
//
// It is 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. It is also
// not safe to call CloseSend concurrently with SendMsg.
SendMsg(m interface{}) error
// RecvMsg blocks until it receives a message into m or the stream is
// done. It returns io.EOF when the stream completes successfully. On
// any other error, the stream is aborted and the error contains the RPC
// status.
//
// It is 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.
RecvMsg(m interface{}) error
}
// NewStream creates a new Stream for the client side. This is typically
// called by generated code. ctx is used for the lifetime of the stream.
//
// To ensure resources are not leaked due to the stream returned, one of the following
// actions must be performed:
//
// 1. Call Close on the ClientConn.
// 2. Cancel the context provided.
// 3. Call RecvMsg until a non-nil error is returned. A protobuf-generated
// client-streaming RPC, for instance, might use the helper function
// CloseAndRecv (note that CloseSend does not Recv, therefore is not
// guaranteed to release all resources).
// 4. Receive a non-nil, non-io.EOF error from Header or SendMsg.
//
// If none of the above happen, a goroutine and a context will be leaked, and grpc
// will not call the optionally-configured stats handler with a stats.End message.
func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method string, opts ...CallOption) (ClientStream, error) {
// allow interceptor to see all applicable call options, which means those
// configured as defaults from dial option as well as per-call options
opts = combine(cc.dopts.callOptions, opts)
if cc.dopts.streamInt != nil {
return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
}
return newClientStream(ctx, desc, cc, method, opts...)
}
// NewClientStream is a wrapper for ClientConn.NewStream.
func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
return cc.NewStream(ctx, desc, method, opts...)
}
func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
if channelz.IsOn() {
cc.incrCallsStarted()
defer func() {
if err != nil {
cc.incrCallsFailed()
}
}()
}
c := defaultCallInfo()
// Provide an opportunity for the first RPC to see the first service config
// provided by the resolver.
if err := cc.waitForResolvedAddrs(ctx); err != nil {
return nil, err
}
mc := cc.GetMethodConfig(method)
if mc.WaitForReady != nil {
c.failFast = !*mc.WaitForReady
}
// Possible context leak:
// The cancel function for the child context we create will only be called
// when RecvMsg returns a non-nil error, if the ClientConn is closed, or if
// an error is generated by SendMsg.
// https://github.com/grpc/grpc-go/issues/1818.
var cancel context.CancelFunc
if mc.Timeout != nil && *mc.Timeout >= 0 {
ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
} else {
ctx, cancel = context.WithCancel(ctx)
}
defer func() {
if err != nil {
cancel()
}
}()
for _, o := range opts {
if err := o.before(c); err != nil {
return nil, toRPCErr(err)
}
}
c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
if err := setCallInfoCodec(c); err != nil {
return nil, err
}
callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
ContentSubtype: c.contentSubtype,
}
// Set our outgoing compression according to the UseCompressor CallOption, if
// set. In that case, also find the compressor from the encoding package.
// Otherwise, use the compressor configured by the WithCompressor DialOption,
// if set.
var cp Compressor
var comp encoding.Compressor
if ct := c.compressorType; ct != "" {
callHdr.SendCompress = ct
if ct != encoding.Identity {
comp = encoding.GetCompressor(ct)
if comp == nil {
return nil, status.Errorf(codes.Internal, "grpc: Compressor is not installed for requested grpc-encoding %q", ct)
}
}
} else if cc.dopts.cp != nil {
callHdr.SendCompress = cc.dopts.cp.Type()
cp = cc.dopts.cp
}
if c.creds != nil {
callHdr.Creds = c.creds
}
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)
}
ctx = newContextWithRPCInfo(ctx, c.failFast)
sh := cc.dopts.copts.StatsHandler
var beginTime time.Time
if sh != nil {
ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
beginTime = time.Now()
begin := &stats.Begin{
Client: true,
BeginTime: beginTime,
FailFast: c.failFast,
}
sh.HandleRPC(ctx, begin)
}
cs := &clientStream{
callHdr: callHdr,
ctx: ctx,
methodConfig: &mc,
opts: opts,
callInfo: c,
cc: cc,
desc: desc,
codec: c.codec,
cp: cp,
comp: comp,
cancel: cancel,
beginTime: beginTime,
firstAttempt: true,
}
if !cc.dopts.disableRetry {
cs.retryThrottler = cc.retryThrottler.Load().(*retryThrottler)
}
cs.binlog = binarylog.GetMethodLogger(method)
cs.callInfo.stream = cs
// Only this initial attempt has stats/tracing.
// TODO(dfawley): move to newAttempt when per-attempt stats are implemented.
if err := cs.newAttemptLocked(sh, trInfo); err != nil {
cs.finish(err)
return nil, err
}
op := func(a *csAttempt) error { return a.newStream() }
if err := cs.withRetry(op, func() { cs.bufferForRetryLocked(0, op) }); err != nil {
cs.finish(err)
return nil, err
}
if cs.binlog != nil {
md, _ := metadata.FromOutgoingContext(ctx)
logEntry := &binarylog.ClientHeader{
OnClientSide: true,
Header: md,
MethodName: method,
Authority: cs.cc.authority,
}
if deadline, ok := ctx.Deadline(); ok {
logEntry.Timeout = deadline.Sub(time.Now())
if logEntry.Timeout < 0 {
logEntry.Timeout = 0
}
}
cs.binlog.Log(logEntry)
}
if desc != unaryStreamDesc {
// Listen on cc and stream contexts to cleanup when the user closes the
// ClientConn or cancels the stream context. In all other cases, an error
// should already be injected into the recv buffer by the transport, which
// the client will eventually receive, and then we will cancel the stream's
// context in clientStream.finish.
go func() {
select {
case <-cc.ctx.Done():
cs.finish(ErrClientConnClosing)
case <-ctx.Done():
cs.finish(toRPCErr(ctx.Err()))
}
}()
}
return cs, nil
}
func (cs *clientStream) newAttemptLocked(sh stats.Handler, trInfo traceInfo) error {
cs.attempt = &csAttempt{
cs: cs,
dc: cs.cc.dopts.dc,
statsHandler: sh,
trInfo: trInfo,
}
if err := cs.ctx.Err(); err != nil {
return toRPCErr(err)
}
t, done, err := cs.cc.getTransport(cs.ctx, cs.callInfo.failFast, cs.callHdr.Method)
if err != nil {
return err
}
cs.attempt.t = t
cs.attempt.done = done
return nil
}
func (a *csAttempt) newStream() error {
cs := a.cs
cs.callHdr.PreviousAttempts = cs.numRetries
s, err := a.t.NewStream(cs.ctx, cs.callHdr)
if err != nil {
return toRPCErr(err)
}
cs.attempt.s = s
cs.attempt.p = &parser{r: s}
return nil
}
// clientStream implements a client side Stream.
type clientStream struct {
callHdr *transport.CallHdr
opts []CallOption
callInfo *callInfo
cc *ClientConn
desc *StreamDesc
codec baseCodec
cp Compressor
comp encoding.Compressor
cancel context.CancelFunc // cancels all attempts
sentLast bool // sent an end stream
beginTime time.Time
methodConfig *MethodConfig
ctx context.Context // the application's context, wrapped by stats/tracing
retryThrottler *retryThrottler // The throttler active when the RPC began.
binlog *binarylog.MethodLogger // Binary logger, can be nil.
// serverHeaderBinlogged is a boolean for whether server header has been
// logged. Server header will be logged when the first time one of those
// happens: stream.Header(), stream.Recv().
//
// It's only read and used by Recv() and Header(), so it doesn't need to be
// synchronized.
serverHeaderBinlogged bool
mu sync.Mutex
firstAttempt bool // if true, transparent retry is valid
numRetries int // exclusive of transparent retry attempt(s)
numRetriesSincePushback int // retries since pushback; to reset backoff
finished bool // TODO: replace with atomic cmpxchg or sync.Once?
attempt *csAttempt // the active client stream attempt
// TODO(hedging): hedging will have multiple attempts simultaneously.
committed bool // active attempt committed for retry?
buffer []func(a *csAttempt) error // operations to replay on retry
bufferSize int // current size of buffer
}
// csAttempt implements a single transport stream attempt within a
// clientStream.
type csAttempt struct {
cs *clientStream
t transport.ClientTransport
s *transport.Stream
p *parser
done func(balancer.DoneInfo)
finished bool
dc Decompressor
decomp encoding.Compressor
decompSet bool
mu sync.Mutex // guards trInfo.tr
// trInfo.tr is set when created (if EnableTracing is true),
// and cleared when the finish method is called.
trInfo traceInfo
statsHandler stats.Handler
}
func (cs *clientStream) commitAttemptLocked() {
cs.committed = true
cs.buffer = nil
}
func (cs *clientStream) commitAttempt() {
cs.mu.Lock()
cs.commitAttemptLocked()
cs.mu.Unlock()
}
// shouldRetry returns nil if the RPC should be retried; otherwise it returns
// the error that should be returned by the operation.
func (cs *clientStream) shouldRetry(err error) error {
if cs.attempt.s == nil && !cs.callInfo.failFast {
// In the event of any error from NewStream (attempt.s == nil), we
// never attempted to write anything to the wire, so we can retry
// indefinitely for non-fail-fast RPCs.
return nil
}
if cs.finished || cs.committed {
// RPC is finished or committed; cannot retry.
return err
}
// Wait for the trailers.
if cs.attempt.s != nil {
<-cs.attempt.s.Done()
}
if cs.firstAttempt && !cs.callInfo.failFast && (cs.attempt.s == nil || cs.attempt.s.Unprocessed()) {
// First attempt, wait-for-ready, stream unprocessed: transparently retry.
cs.firstAttempt = false
return nil
}
cs.firstAttempt = false
if cs.cc.dopts.disableRetry {
return err
}
pushback := 0
hasPushback := false
if cs.attempt.s != nil {
if to, toErr := cs.attempt.s.TrailersOnly(); toErr != nil {
// Context error; stop now.
return toErr
} else if !to {
return err
}
// TODO(retry): Move down if the spec changes to not check server pushback
// before considering this a failure for throttling.
sps := cs.attempt.s.Trailer()["grpc-retry-pushback-ms"]
if len(sps) == 1 {
var e error
if pushback, e = strconv.Atoi(sps[0]); e != nil || pushback < 0 {
grpclog.Infof("Server retry pushback specified to abort (%q).", sps[0])
cs.retryThrottler.throttle() // This counts as a failure for throttling.
return err
}
hasPushback = true
} else if len(sps) > 1 {
grpclog.Warningf("Server retry pushback specified multiple values (%q); not retrying.", sps)
cs.retryThrottler.throttle() // This counts as a failure for throttling.
return err
}
}
var code codes.Code
if cs.attempt.s != nil {
code = cs.attempt.s.Status().Code()
} else {
code = status.Convert(err).Code()
}
rp := cs.methodConfig.retryPolicy
if rp == nil || !rp.retryableStatusCodes[code] {
return err
}
// Note: the ordering here is important; we count this as a failure
// only if the code matched a retryable code.
if cs.retryThrottler.throttle() {
return err
}
if cs.numRetries+1 >= rp.maxAttempts {
return err
}
var dur time.Duration
if hasPushback {
dur = time.Millisecond * time.Duration(pushback)
cs.numRetriesSincePushback = 0
} else {
fact := math.Pow(rp.backoffMultiplier, float64(cs.numRetriesSincePushback))
cur := float64(rp.initialBackoff) * fact
if max := float64(rp.maxBackoff); cur > max {
cur = max
}
dur = time.Duration(grpcrand.Int63n(int64(cur)))
cs.numRetriesSincePushback++
}
// TODO(dfawley): we could eagerly fail here if dur puts us past the
// deadline, but unsure if it is worth doing.
t := time.NewTimer(dur)
select {
case <-t.C:
cs.numRetries++
return nil
case <-cs.ctx.Done():
t.Stop()
return status.FromContextError(cs.ctx.Err()).Err()
}
}
// Returns nil if a retry was performed and succeeded; error otherwise.
func (cs *clientStream) retryLocked(lastErr error) error {
for {
cs.attempt.finish(lastErr)
if err := cs.shouldRetry(lastErr); err != nil {
cs.commitAttemptLocked()
return err
}
if err := cs.newAttemptLocked(nil, traceInfo{}); err != nil {
return err
}
if lastErr = cs.replayBufferLocked(); lastErr == nil {
return nil
}
}
}
func (cs *clientStream) Context() context.Context {
cs.commitAttempt()
// No need to lock before using attempt, since we know it is committed and
// cannot change.
return cs.attempt.s.Context()
}
func (cs *clientStream) withRetry(op func(a *csAttempt) error, onSuccess func()) error {
cs.mu.Lock()
for {
if cs.committed {
cs.mu.Unlock()
return op(cs.attempt)
}
a := cs.attempt
cs.mu.Unlock()
err := op(a)
cs.mu.Lock()
if a != cs.attempt {
// We started another attempt already.
continue
}
if err == io.EOF {
<-a.s.Done()
}
if err == nil || (err == io.EOF && a.s.Status().Code() == codes.OK) {
onSuccess()
cs.mu.Unlock()
return err
}
if err := cs.retryLocked(err); err != nil {
cs.mu.Unlock()
return err
}
}
}
func (cs *clientStream) Header() (metadata.MD, error) {
var m metadata.MD
err := cs.withRetry(func(a *csAttempt) error {
var err error
m, err = a.s.Header()
return toRPCErr(err)
}, cs.commitAttemptLocked)
if err != nil {
cs.finish(err)
return nil, err
}
if cs.binlog != nil && !cs.serverHeaderBinlogged {
// Only log if binary log is on and header has not been logged.
logEntry := &binarylog.ServerHeader{
OnClientSide: true,
Header: m,
PeerAddr: nil,
}
if peer, ok := peer.FromContext(cs.Context()); ok {
logEntry.PeerAddr = peer.Addr
}
cs.binlog.Log(logEntry)
cs.serverHeaderBinlogged = true
}
return m, err
}
func (cs *clientStream) Trailer() metadata.MD {
// On RPC failure, we never need to retry, because usage requires that
// RecvMsg() returned a non-nil error before calling this function is valid.
// We would have retried earlier if necessary.
//
// Commit the attempt anyway, just in case users are not following those
// directions -- it will prevent races and should not meaningfully impact
// performance.
cs.commitAttempt()
if cs.attempt.s == nil {
return nil
}
return cs.attempt.s.Trailer()
}
func (cs *clientStream) replayBufferLocked() error {
a := cs.attempt
for _, f := range cs.buffer {
if err := f(a); err != nil {
return err
}
}
return nil
}
func (cs *clientStream) bufferForRetryLocked(sz int, op func(a *csAttempt) error) {
// Note: we still will buffer if retry is disabled (for transparent retries).
if cs.committed {
return
}
cs.bufferSize += sz
if cs.bufferSize > cs.callInfo.maxRetryRPCBufferSize {
cs.commitAttemptLocked()
return
}
cs.buffer = append(cs.buffer, op)
}
func (cs *clientStream) SendMsg(m interface{}) (err error) {
defer func() {
if err != nil && err != io.EOF {
// Call finish on the client stream for errors generated by this SendMsg
// call, as these indicate problems created by this client. (Transport
// errors are converted to an io.EOF error in csAttempt.sendMsg; the real
// error will be returned from RecvMsg eventually in that case, or be
// retried.)
cs.finish(err)
}
}()
if cs.sentLast {
return status.Errorf(codes.Internal, "SendMsg called after CloseSend")
}
if !cs.desc.ClientStreams {
cs.sentLast = true
}
data, err := encode(cs.codec, m)
if err != nil {
return err
}
compData, err := compress(data, cs.cp, cs.comp)
if err != nil {
return err
}
hdr, payload := msgHeader(data, compData)
// TODO(dfawley): should we be checking len(data) instead?
if len(payload) > *cs.callInfo.maxSendMessageSize {
return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payload), *cs.callInfo.maxSendMessageSize)
}
msgBytes := data // Store the pointer before setting to nil. For binary logging.
op := func(a *csAttempt) error {
err := a.sendMsg(m, hdr, payload, data)
// nil out the message and uncomp when replaying; they are only needed for
// stats which is disabled for subsequent attempts.
m, data = nil, nil
return err
}
err = cs.withRetry(op, func() { cs.bufferForRetryLocked(len(hdr)+len(payload), op) })
if cs.binlog != nil && err == nil {
cs.binlog.Log(&binarylog.ClientMessage{
OnClientSide: true,
Message: msgBytes,
})
}
return
}
func (cs *clientStream) RecvMsg(m interface{}) error {
if cs.binlog != nil && !cs.serverHeaderBinlogged {
// Call Header() to binary log header if it's not already logged.
cs.Header()
}
var recvInfo *payloadInfo
if cs.binlog != nil {
recvInfo = &payloadInfo{}
}
err := cs.withRetry(func(a *csAttempt) error {
return a.recvMsg(m, recvInfo)
}, cs.commitAttemptLocked)
if cs.binlog != nil && err == nil {
cs.binlog.Log(&binarylog.ServerMessage{
OnClientSide: true,
Message: recvInfo.uncompressedBytes,
})
}
if err != nil || !cs.desc.ServerStreams {
// err != nil or non-server-streaming indicates end of stream.
cs.finish(err)
if cs.binlog != nil {
// finish will not log Trailer. Log Trailer here.
logEntry := &binarylog.ServerTrailer{
OnClientSide: true,
Trailer: cs.Trailer(),
Err: err,
}
if logEntry.Err == io.EOF {
logEntry.Err = nil
}
if peer, ok := peer.FromContext(cs.Context()); ok {
logEntry.PeerAddr = peer.Addr
}
cs.binlog.Log(logEntry)
}
}
return err
}
func (cs *clientStream) CloseSend() error {
if cs.sentLast {
// TODO: return an error and finish the stream instead, due to API misuse?
return nil
}
cs.sentLast = true
op := func(a *csAttempt) error {
a.t.Write(a.s, nil, nil, &transport.Options{Last: true})
// Always return nil; io.EOF is the only error that might make sense
// instead, but there is no need to signal the client to call RecvMsg
// as the only use left for the stream after CloseSend is to call
// RecvMsg. This also matches historical behavior.
return nil
}
cs.withRetry(op, func() { cs.bufferForRetryLocked(0, op) })
if cs.binlog != nil {
cs.binlog.Log(&binarylog.ClientHalfClose{
OnClientSide: true,
})
}
// We never returned an error here for reasons.
return nil
}
func (cs *clientStream) finish(err error) {
if err == io.EOF {
// Ending a stream with EOF indicates a success.
err = nil
}
cs.mu.Lock()
if cs.finished {
cs.mu.Unlock()
return
}
cs.finished = true
cs.commitAttemptLocked()
cs.mu.Unlock()
// For binary logging. only log cancel in finish (could be caused by RPC ctx
// canceled or ClientConn closed). Trailer will be logged in RecvMsg.
//
// Only one of cancel or trailer needs to be logged. In the cases where
// users don't call RecvMsg, users must have already canceled the RPC.
if cs.binlog != nil && status.Code(err) == codes.Canceled {
cs.binlog.Log(&binarylog.Cancel{
OnClientSide: true,
})
}
if err == nil {
cs.retryThrottler.successfulRPC()
}
if channelz.IsOn() {
if err != nil {
cs.cc.incrCallsFailed()
} else {
cs.cc.incrCallsSucceeded()
}
}
if cs.attempt != nil {
cs.attempt.finish(err)
}
// after functions all rely upon having a stream.
if cs.attempt.s != nil {
for _, o := range cs.opts {
o.after(cs.callInfo)
}
}
cs.cancel()
}
func (a *csAttempt) sendMsg(m interface{}, hdr, payld, data []byte) error {
cs := a.cs
if EnableTracing {
a.mu.Lock()
if a.trInfo.tr != nil {
a.trInfo.tr.LazyLog(&payload{sent: true, msg: m}, true)
}
a.mu.Unlock()
}
if err := a.t.Write(a.s, hdr, payld, &transport.Options{Last: !cs.desc.ClientStreams}); err != nil {
if !cs.desc.ClientStreams {
// For non-client-streaming RPCs, we return nil instead of EOF on error
// because the generated code requires it. finish is not called; RecvMsg()
// will call it with the stream's status independently.
return nil
}
return io.EOF
}
if a.statsHandler != nil {
a.statsHandler.HandleRPC(cs.ctx, outPayload(true, m, data, payld, time.Now()))
}
if channelz.IsOn() {
a.t.IncrMsgSent()
}
return nil
}
func (a *csAttempt) recvMsg(m interface{}, payInfo *payloadInfo) (err error) {
cs := a.cs
if a.statsHandler != nil && payInfo == nil {
payInfo = &payloadInfo{}
}
if !a.decompSet {
// Block until we receive headers containing received message encoding.
if ct := a.s.RecvCompress(); ct != "" && ct != encoding.Identity {
if a.dc == nil || a.dc.Type() != ct {
// No configured decompressor, or it does not match the incoming
// message encoding; attempt to find a registered compressor that does.
a.dc = nil
a.decomp = encoding.GetCompressor(ct)
}
} else {
// No compression is used; disable our decompressor.
a.dc = nil
}
// Only initialize this state once per stream.
a.decompSet = true
}
err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.callInfo.maxReceiveMessageSize, payInfo, a.decomp)
if err != nil {
if err == io.EOF {
if statusErr := a.s.Status().Err(); statusErr != nil {
return statusErr
}
return io.EOF // indicates successful end of stream.
}
return toRPCErr(err)
}
if EnableTracing {
a.mu.Lock()
if a.trInfo.tr != nil {
a.trInfo.tr.LazyLog(&payload{sent: false, msg: m}, true)
}
a.mu.Unlock()
}
if a.statsHandler != nil {
a.statsHandler.HandleRPC(cs.ctx, &stats.InPayload{
Client: true,
RecvTime: time.Now(),
Payload: m,
// TODO truncate large payload.
Data: payInfo.uncompressedBytes,
Length: len(payInfo.uncompressedBytes),
})
}
if channelz.IsOn() {
a.t.IncrMsgRecv()
}
if cs.desc.ServerStreams {
// Subsequent messages should be received by subsequent RecvMsg calls.
return nil
}
// Special handling for non-server-stream rpcs.
// This recv expects EOF or errors, so we don't collect inPayload.
err = recv(a.p, cs.codec, a.s, a.dc, m, *cs.callInfo.maxReceiveMessageSize, nil, a.decomp)
if err == nil {
return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
}
if err == io.EOF {
return a.s.Status().Err() // non-server streaming Recv returns nil on success
}
return toRPCErr(err)
}
func (a *csAttempt) finish(err error) {
a.mu.Lock()
if a.finished {
a.mu.Unlock()
return
}
a.finished = true
if err == io.EOF {
// Ending a stream with EOF indicates a success.
err = nil
}
if a.s != nil {
a.t.CloseStream(a.s, err)
}
if a.done != nil {
br := false
var tr metadata.MD
if a.s != nil {
br = a.s.BytesReceived()
tr = a.s.Trailer()
}
a.done(balancer.DoneInfo{
Err: err,
Trailer: tr,
BytesSent: a.s != nil,
BytesReceived: br,
})
}
if a.statsHandler != nil {
end := &stats.End{
Client: true,
BeginTime: a.cs.beginTime,
EndTime: time.Now(),
Error: err,
}
a.statsHandler.HandleRPC(a.cs.ctx, end)
}
if a.trInfo.tr != nil {
if err == nil {
a.trInfo.tr.LazyPrintf("RPC: [OK]")
} else {
a.trInfo.tr.LazyPrintf("RPC: [%v]", err)
a.trInfo.tr.SetError()
}
a.trInfo.tr.Finish()
a.trInfo.tr = nil
}
a.mu.Unlock()
}
func (ac *addrConn) newClientStream(ctx context.Context, desc *StreamDesc, method string, t transport.ClientTransport, opts ...CallOption) (_ ClientStream, err error) {
ac.mu.Lock()
if ac.transport != t {
ac.mu.Unlock()
return nil, status.Error(codes.Canceled, "the provided transport is no longer valid to use")
}
// transition to CONNECTING state when an attempt starts
if ac.state != connectivity.Connecting {
ac.updateConnectivityState(connectivity.Connecting)
ac.cc.handleSubConnStateChange(ac.acbw, ac.state)
}
ac.mu.Unlock()
if t == nil {
// TODO: return RPC error here?
return nil, errors.New("transport provided is nil")
}
// defaultCallInfo contains unnecessary info(i.e. failfast, maxRetryRPCBufferSize), so we just initialize an empty struct.
c := &callInfo{}
for _, o := range opts {
if err := o.before(c); err != nil {
return nil, toRPCErr(err)
}
}
c.maxReceiveMessageSize = getMaxSize(nil, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
c.maxSendMessageSize = getMaxSize(nil, c.maxSendMessageSize, defaultServerMaxSendMessageSize)
// Possible context leak:
// The cancel function for the child context we create will only be called
// when RecvMsg returns a non-nil error, if the ClientConn is closed, or if
// an error is generated by SendMsg.
// https://github.com/grpc/grpc-go/issues/1818.
ctx, cancel := context.WithCancel(ctx)
defer func() {
if err != nil {
cancel()
}
}()
if err := setCallInfoCodec(c); err != nil {
return nil, err
}
callHdr := &transport.CallHdr{
Host: ac.cc.authority,
Method: method,
ContentSubtype: c.contentSubtype,
}
// Set our outgoing compression according to the UseCompressor CallOption, if
// set. In that case, also find the compressor from the encoding package.
// Otherwise, use the compressor configured by the WithCompressor DialOption,
// if set.
var cp Compressor
var comp encoding.Compressor
if ct := c.compressorType; ct != "" {
callHdr.SendCompress = ct
if ct != encoding.Identity {
comp = encoding.GetCompressor(ct)
if comp == nil {
return nil, status.Errorf(codes.Internal, "grpc: Compressor is not installed for requested grpc-encoding %q", ct)
}
}
} else if ac.cc.dopts.cp != nil {
callHdr.SendCompress = ac.cc.dopts.cp.Type()
cp = ac.cc.dopts.cp
}
if c.creds != nil {
callHdr.Creds = c.creds
}
as := &addrConnStream{
callHdr: callHdr,
ac: ac,
ctx: ctx,
cancel: cancel,
opts: opts,
callInfo: c,
desc: desc,
codec: c.codec,
cp: cp,
comp: comp,
t: t,
}
as.callInfo.stream = as
s, err := as.t.NewStream(as.ctx, as.callHdr)
if err != nil {
err = toRPCErr(err)
return nil, err
}
as.s = s
as.p = &parser{r: s}
ac.incrCallsStarted()
if desc != unaryStreamDesc {
// Listen on cc and stream contexts to cleanup when the user closes the
// ClientConn or cancels the stream context. In all other cases, an error
// should already be injected into the recv buffer by the transport, which
// the client will eventually receive, and then we will cancel the stream's
// context in clientStream.finish.
go func() {
select {
case <-ac.ctx.Done():
as.finish(status.Error(codes.Canceled, "grpc: the SubConn is closing"))
case <-ctx.Done():
as.finish(toRPCErr(ctx.Err()))
}
}()
}
return as, nil
}
type addrConnStream struct {
s *transport.Stream
ac *addrConn
callHdr *transport.CallHdr
cancel context.CancelFunc
opts []CallOption
callInfo *callInfo
t transport.ClientTransport
ctx context.Context
sentLast bool
desc *StreamDesc
codec baseCodec
cp Compressor
comp encoding.Compressor
decompSet bool
dc Decompressor
decomp encoding.Compressor
p *parser
done func(balancer.DoneInfo)
mu sync.Mutex
finished bool
}
func (as *addrConnStream) Header() (metadata.MD, error) {
m, err := as.s.Header()
if err != nil {
as.finish(toRPCErr(err))
}
return m, err
}
func (as *addrConnStream) Trailer() metadata.MD {
return as.s.Trailer()
}
func (as *addrConnStream) CloseSend() error {
if as.sentLast {
// TODO: return an error and finish the stream instead, due to API misuse?
return nil
}
as.sentLast = true
as.t.Write(as.s, nil, nil, &transport.Options{Last: true})
// Always return nil; io.EOF is the only error that might make sense
// instead, but there is no need to signal the client to call RecvMsg
// as the only use left for the stream after CloseSend is to call
// RecvMsg. This also matches historical behavior.
return nil
}
func (as *addrConnStream) Context() context.Context {
return as.s.Context()
}
func (as *addrConnStream) SendMsg(m interface{}) (err error) {
defer func() {
if err != nil && err != io.EOF {
// Call finish on the client stream for errors generated by this SendMsg
// call, as these indicate problems created by this client. (Transport
// errors are converted to an io.EOF error in csAttempt.sendMsg; the real
// error will be returned from RecvMsg eventually in that case, or be
// retried.)
as.finish(err)
}
}()
if as.sentLast {
return status.Errorf(codes.Internal, "SendMsg called after CloseSend")
}
if !as.desc.ClientStreams {
as.sentLast = true
}
data, err := encode(as.codec, m)
if err != nil {
return err
}
compData, err := compress(data, as.cp, as.comp)
if err != nil {
return err
}
hdr, payld := msgHeader(data, compData)
// TODO(dfawley): should we be checking len(data) instead?
if len(payld) > *as.callInfo.maxSendMessageSize {
return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payld), *as.callInfo.maxSendMessageSize)
}
if err := as.t.Write(as.s, hdr, payld, &transport.Options{Last: !as.desc.ClientStreams}); err != nil {
if !as.desc.ClientStreams {
// For non-client-streaming RPCs, we return nil instead of EOF on error
// because the generated code requires it. finish is not called; RecvMsg()
// will call it with the stream's status independently.
return nil
}
return io.EOF
}
if channelz.IsOn() {
as.t.IncrMsgSent()
}
return nil
}
func (as *addrConnStream) RecvMsg(m interface{}) (err error) {
defer func() {
if err != nil || !as.desc.ServerStreams {
// err != nil or non-server-streaming indicates end of stream.
as.finish(err)
}
}()
if !as.decompSet {
// Block until we receive headers containing received message encoding.
if ct := as.s.RecvCompress(); ct != "" && ct != encoding.Identity {
if as.dc == nil || as.dc.Type() != ct {
// No configured decompressor, or it does not match the incoming
// message encoding; attempt to find a registered compressor that does.
as.dc = nil
as.decomp = encoding.GetCompressor(ct)
}
} else {
// No compression is used; disable our decompressor.
as.dc = nil
}
// Only initialize this state once per stream.
as.decompSet = true
}
err = recv(as.p, as.codec, as.s, as.dc, m, *as.callInfo.maxReceiveMessageSize, nil, as.decomp)
if err != nil {
if err == io.EOF {
if statusErr := as.s.Status().Err(); statusErr != nil {
return statusErr
}
return io.EOF // indicates successful end of stream.
}
return toRPCErr(err)
}
if channelz.IsOn() {
as.t.IncrMsgRecv()
}
if as.desc.ServerStreams {
// Subsequent messages should be received by subsequent RecvMsg calls.
return nil
}
// Special handling for non-server-stream rpcs.
// This recv expects EOF or errors, so we don't collect inPayload.
err = recv(as.p, as.codec, as.s, as.dc, m, *as.callInfo.maxReceiveMessageSize, nil, as.decomp)
if err == nil {
return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
}
if err == io.EOF {
return as.s.Status().Err() // non-server streaming Recv returns nil on success
}
return toRPCErr(err)
}
func (as *addrConnStream) finish(err error) {
as.mu.Lock()
if as.finished {
as.mu.Unlock()
return
}
as.finished = true
if err == io.EOF {
// Ending a stream with EOF indicates a success.
err = nil
}
if as.s != nil {
as.t.CloseStream(as.s, err)
}
if err != nil {
as.ac.incrCallsFailed()
} else {
as.ac.incrCallsSucceeded()
}
as.cancel()
as.mu.Unlock()
}
// ServerStream defines the server-side behavior of a streaming RPC.
//
// All errors returned from ServerStream methods are compatible with the
// status package.
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)
// Context returns the context for this stream.
Context() context.Context
// SendMsg sends a message. On error, SendMsg aborts the stream and the
// error is returned directly.
//
// SendMsg blocks until:
// - There is sufficient flow control to schedule m with the transport, or
// - The stream is done, or
// - The stream breaks.
//
// SendMsg does not wait until the message is received by the client. An
// untimely stream closure may result in lost messages.
//
// It is 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.
SendMsg(m interface{}) error
// RecvMsg blocks until it receives a message into m or the stream is
// done. It returns io.EOF when the client has performed a CloseSend. On
// any non-EOF error, the stream is aborted and the error contains the
// RPC status.
//
// It is 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.
RecvMsg(m interface{}) error
}
// serverStream implements a server side Stream.
type serverStream struct {
ctx context.Context
t transport.ServerTransport
s *transport.Stream
p *parser
codec baseCodec
cp Compressor
dc Decompressor
comp encoding.Compressor
decomp encoding.Compressor
maxReceiveMessageSize int
maxSendMessageSize int
trInfo *traceInfo
statsHandler stats.Handler
binlog *binarylog.MethodLogger
// serverHeaderBinlogged indicates whether server header has been logged. It
// will happen when one of the following two happens: stream.SendHeader(),
// stream.Send().
//
// It's only checked in send and sendHeader, doesn't need to be
// synchronized.
serverHeaderBinlogged bool
mu sync.Mutex // protects trInfo.tr after the service handler runs.
}
func (ss *serverStream) Context() context.Context {
return ss.ctx
}
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 {
err := ss.t.WriteHeader(ss.s, md)
if ss.binlog != nil && !ss.serverHeaderBinlogged {
h, _ := ss.s.Header()
ss.binlog.Log(&binarylog.ServerHeader{
Header: h,
})
ss.serverHeaderBinlogged = true
}
return err
}
func (ss *serverStream) SetTrailer(md metadata.MD) {
if md.Len() == 0 {
return
}
ss.s.SetTrailer(md)
}
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()
}
if err != nil && err != io.EOF {
st, _ := status.FromError(toRPCErr(err))
ss.t.WriteStatus(ss.s, st)
// Non-user specified status was sent out. This should be an error
// case (as a server side Cancel maybe).
//
// This is not handled specifically now. User will return a final
// status from the service handler, we will log that error instead.
// This behavior is similar to an interceptor.
}
if channelz.IsOn() && err == nil {
ss.t.IncrMsgSent()
}
}()
data, err := encode(ss.codec, m)
if err != nil {
return err
}
compData, err := compress(data, ss.cp, ss.comp)
if err != nil {
return err
}
hdr, payload := msgHeader(data, compData)
// TODO(dfawley): should we be checking len(data) instead?
if len(payload) > ss.maxSendMessageSize {
return status.Errorf(codes.ResourceExhausted, "trying to send message larger than max (%d vs. %d)", len(payload), ss.maxSendMessageSize)
}
if err := ss.t.Write(ss.s, hdr, payload, &transport.Options{Last: false}); err != nil {
return toRPCErr(err)
}
if ss.binlog != nil {
if !ss.serverHeaderBinlogged {
h, _ := ss.s.Header()
ss.binlog.Log(&binarylog.ServerHeader{
Header: h,
})
ss.serverHeaderBinlogged = true
}
ss.binlog.Log(&binarylog.ServerMessage{
Message: data,
})
}
if ss.statsHandler != nil {
ss.statsHandler.HandleRPC(ss.s.Context(), outPayload(false, m, data, payload, time.Now()))
}
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()
}
if err != nil && err != io.EOF {
st, _ := status.FromError(toRPCErr(err))
ss.t.WriteStatus(ss.s, st)
// Non-user specified status was sent out. This should be an error
// case (as a server side Cancel maybe).
//
// This is not handled specifically now. User will return a final
// status from the service handler, we will log that error instead.
// This behavior is similar to an interceptor.
}
if channelz.IsOn() && err == nil {
ss.t.IncrMsgRecv()
}
}()
var payInfo *payloadInfo
if ss.statsHandler != nil || ss.binlog != nil {
payInfo = &payloadInfo{}
}
if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxReceiveMessageSize, payInfo, ss.decomp); err != nil {
if err == io.EOF {
if ss.binlog != nil {
ss.binlog.Log(&binarylog.ClientHalfClose{})
}
return err
}
if err == io.ErrUnexpectedEOF {
err = status.Errorf(codes.Internal, io.ErrUnexpectedEOF.Error())
}
return toRPCErr(err)
}
if ss.statsHandler != nil {
ss.statsHandler.HandleRPC(ss.s.Context(), &stats.InPayload{
RecvTime: time.Now(),
Payload: m,
// TODO truncate large payload.
Data: payInfo.uncompressedBytes,
Length: len(payInfo.uncompressedBytes),
})
}
if ss.binlog != nil {
ss.binlog.Log(&binarylog.ClientMessage{
Message: payInfo.uncompressedBytes,
})
}
return nil
}
// MethodFromServerStream returns the method string for the input stream.
// The returned string is in the format of "/service/method".
func MethodFromServerStream(stream ServerStream) (string, bool) {
return Method(stream.Context())
}