traefik/vendor/google.golang.org/grpc/call.go
2017-11-29 13:26:03 +01:00

309 lines
9.2 KiB
Go

/*
*
* 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 (
"bytes"
"io"
"time"
"golang.org/x/net/context"
"golang.org/x/net/trace"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/stats"
"google.golang.org/grpc/status"
"google.golang.org/grpc/transport"
)
// recvResponse receives and parses an RPC response.
// On error, it returns the error and indicates whether the call should be retried.
//
// TODO(zhaoq): Check whether the received message sequence is valid.
// TODO ctx is used for stats collection and processing. It is the context passed from the application.
func recvResponse(ctx context.Context, dopts dialOptions, t transport.ClientTransport, c *callInfo, stream *transport.Stream, reply interface{}) (err error) {
// Try to acquire header metadata from the server if there is any.
defer func() {
if err != nil {
if _, ok := err.(transport.ConnectionError); !ok {
t.CloseStream(stream, err)
}
}
}()
c.headerMD, err = stream.Header()
if err != nil {
return
}
p := &parser{r: stream}
var inPayload *stats.InPayload
if dopts.copts.StatsHandler != nil {
inPayload = &stats.InPayload{
Client: true,
}
}
for {
if c.maxReceiveMessageSize == nil {
return Errorf(codes.Internal, "callInfo maxReceiveMessageSize field uninitialized(nil)")
}
if err = recv(p, dopts.codec, stream, dopts.dc, reply, *c.maxReceiveMessageSize, inPayload); err != nil {
if err == io.EOF {
break
}
return
}
}
if inPayload != nil && err == io.EOF && stream.Status().Code() == codes.OK {
// TODO in the current implementation, inTrailer may be handled before inPayload in some cases.
// Fix the order if necessary.
dopts.copts.StatsHandler.HandleRPC(ctx, inPayload)
}
c.trailerMD = stream.Trailer()
return nil
}
// sendRequest writes out various information of an RPC such as Context and Message.
func sendRequest(ctx context.Context, dopts dialOptions, compressor Compressor, c *callInfo, callHdr *transport.CallHdr, stream *transport.Stream, t transport.ClientTransport, args interface{}, opts *transport.Options) (err error) {
defer func() {
if err != nil {
// If err is connection error, t will be closed, no need to close stream here.
if _, ok := err.(transport.ConnectionError); !ok {
t.CloseStream(stream, err)
}
}
}()
var (
cbuf *bytes.Buffer
outPayload *stats.OutPayload
)
if compressor != nil {
cbuf = new(bytes.Buffer)
}
if dopts.copts.StatsHandler != nil {
outPayload = &stats.OutPayload{
Client: true,
}
}
outBuf, err := encode(dopts.codec, args, compressor, cbuf, outPayload)
if err != nil {
return err
}
if c.maxSendMessageSize == nil {
return Errorf(codes.Internal, "callInfo maxSendMessageSize field uninitialized(nil)")
}
if len(outBuf) > *c.maxSendMessageSize {
return Errorf(codes.ResourceExhausted, "grpc: trying to send message larger than max (%d vs. %d)", len(outBuf), *c.maxSendMessageSize)
}
err = t.Write(stream, outBuf, opts)
if err == nil && outPayload != nil {
outPayload.SentTime = time.Now()
dopts.copts.StatsHandler.HandleRPC(ctx, outPayload)
}
// t.NewStream(...) could lead to an early rejection of the RPC (e.g., the service/method
// does not exist.) so that t.Write could get io.EOF from wait(...). Leave the following
// recvResponse to get the final status.
if err != nil && err != io.EOF {
return err
}
// Sent successfully.
return nil
}
// Invoke sends the RPC request on the wire and returns after response is received.
// Invoke is called by generated code. Also users can call Invoke directly when it
// is really needed in their use cases.
func Invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) error {
if cc.dopts.unaryInt != nil {
return cc.dopts.unaryInt(ctx, method, args, reply, cc, invoke, opts...)
}
return invoke(ctx, method, args, reply, cc, opts...)
}
func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (e error) {
c := defaultCallInfo
mc := cc.GetMethodConfig(method)
if mc.WaitForReady != nil {
c.failFast = !*mc.WaitForReady
}
if mc.Timeout != nil && *mc.Timeout >= 0 {
var cancel context.CancelFunc
ctx, cancel = context.WithTimeout(ctx, *mc.Timeout)
defer cancel()
}
opts = append(cc.dopts.callOptions, opts...)
for _, o := range opts {
if err := o.before(&c); err != nil {
return toRPCErr(err)
}
}
defer func() {
for _, o := range opts {
o.after(&c)
}
}()
c.maxSendMessageSize = getMaxSize(mc.MaxReqSize, c.maxSendMessageSize, defaultClientMaxSendMessageSize)
c.maxReceiveMessageSize = getMaxSize(mc.MaxRespSize, c.maxReceiveMessageSize, defaultClientMaxReceiveMessageSize)
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 e != nil {
c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{e}}, true)
c.traceInfo.tr.SetError()
}
}()
}
ctx = newContextWithRPCInfo(ctx)
sh := cc.dopts.copts.StatsHandler
if sh != nil {
ctx = sh.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method, FailFast: c.failFast})
begin := &stats.Begin{
Client: true,
BeginTime: time.Now(),
FailFast: c.failFast,
}
sh.HandleRPC(ctx, begin)
defer func() {
end := &stats.End{
Client: true,
EndTime: time.Now(),
Error: e,
}
sh.HandleRPC(ctx, end)
}()
}
topts := &transport.Options{
Last: true,
Delay: false,
}
for {
var (
err error
t transport.ClientTransport
stream *transport.Stream
// Record the put handler from Balancer.Get(...). It is called once the
// RPC has completed or failed.
put func()
)
// TODO(zhaoq): Need a formal spec of fail-fast.
callHdr := &transport.CallHdr{
Host: cc.authority,
Method: method,
}
if cc.dopts.cp != nil {
callHdr.SendCompress = cc.dopts.cp.Type()
}
if c.creds != nil {
callHdr.Creds = c.creds
}
gopts := BalancerGetOptions{
BlockingWait: !c.failFast,
}
t, put, err = cc.getTransport(ctx, gopts)
if err != nil {
// TODO(zhaoq): Probably revisit the error handling.
if _, ok := status.FromError(err); ok {
return err
}
if err == errConnClosing || err == errConnUnavailable {
if c.failFast {
return Errorf(codes.Unavailable, "%v", err)
}
continue
}
// All the other errors are treated as Internal errors.
return Errorf(codes.Internal, "%v", err)
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: true, msg: args}, true)
}
stream, err = t.NewStream(ctx, callHdr)
if err != nil {
if put != nil {
if _, ok := err.(transport.ConnectionError); ok {
// 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})
}
put()
}
if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
continue
}
return toRPCErr(err)
}
if peer, ok := peer.FromContext(stream.Context()); ok {
c.peer = peer
}
err = sendRequest(ctx, cc.dopts, cc.dopts.cp, &c, callHdr, stream, t, args, topts)
if err != nil {
if put != nil {
updateRPCInfoInContext(ctx, rpcInfo{
bytesSent: stream.BytesSent(),
bytesReceived: stream.BytesReceived(),
})
put()
}
// Retry a non-failfast RPC when
// i) there is a connection error; or
// ii) the server started to drain before this RPC was initiated.
if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
continue
}
return toRPCErr(err)
}
err = recvResponse(ctx, cc.dopts, t, &c, stream, reply)
if err != nil {
if put != nil {
updateRPCInfoInContext(ctx, rpcInfo{
bytesSent: stream.BytesSent(),
bytesReceived: stream.BytesReceived(),
})
put()
}
if _, ok := err.(transport.ConnectionError); (ok || err == transport.ErrStreamDrain) && !c.failFast {
continue
}
return toRPCErr(err)
}
if c.traceInfo.tr != nil {
c.traceInfo.tr.LazyLog(&payload{sent: false, msg: reply}, true)
}
t.CloseStream(stream, nil)
if put != nil {
updateRPCInfoInContext(ctx, rpcInfo{
bytesSent: stream.BytesSent(),
bytesReceived: stream.BytesReceived(),
})
put()
}
return stream.Status().Err()
}
}