1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
|
/*
*
* Copyright 2016 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.
*
*/
// This file is the implementation of a gRPC server using HTTP/2 which
// uses the standard Go http2 Server implementation (via the
// http.Handler interface), rather than speaking low-level HTTP/2
// frames itself. It is the implementation of *grpc.Server.ServeHTTP.
package transport
import (
"errors"
"fmt"
"io"
"net"
"net/http"
"strings"
"sync"
"time"
"golang.org/x/net/context"
"golang.org/x/net/http2"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/metadata"
"google.golang.org/grpc/peer"
"google.golang.org/grpc/status"
)
// NewServerHandlerTransport returns a ServerTransport handling gRPC
// from inside an http.Handler. It requires that the http Server
// supports HTTP/2.
func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request) (ServerTransport, error) {
if r.ProtoMajor != 2 {
return nil, errors.New("gRPC requires HTTP/2")
}
if r.Method != "POST" {
return nil, errors.New("invalid gRPC request method")
}
if !validContentType(r.Header.Get("Content-Type")) {
return nil, errors.New("invalid gRPC request content-type")
}
if _, ok := w.(http.Flusher); !ok {
return nil, errors.New("gRPC requires a ResponseWriter supporting http.Flusher")
}
if _, ok := w.(http.CloseNotifier); !ok {
return nil, errors.New("gRPC requires a ResponseWriter supporting http.CloseNotifier")
}
st := &serverHandlerTransport{
rw: w,
req: r,
closedCh: make(chan struct{}),
writes: make(chan func()),
}
if v := r.Header.Get("grpc-timeout"); v != "" {
to, err := decodeTimeout(v)
if err != nil {
return nil, streamErrorf(codes.Internal, "malformed time-out: %v", err)
}
st.timeoutSet = true
st.timeout = to
}
var metakv []string
if r.Host != "" {
metakv = append(metakv, ":authority", r.Host)
}
for k, vv := range r.Header {
k = strings.ToLower(k)
if isReservedHeader(k) && !isWhitelistedPseudoHeader(k) {
continue
}
for _, v := range vv {
v, err := decodeMetadataHeader(k, v)
if err != nil {
return nil, streamErrorf(codes.InvalidArgument, "malformed binary metadata: %v", err)
}
metakv = append(metakv, k, v)
}
}
st.headerMD = metadata.Pairs(metakv...)
return st, nil
}
// serverHandlerTransport is an implementation of ServerTransport
// which replies to exactly one gRPC request (exactly one HTTP request),
// using the net/http.Handler interface. This http.Handler is guaranteed
// at this point to be speaking over HTTP/2, so it's able to speak valid
// gRPC.
type serverHandlerTransport struct {
rw http.ResponseWriter
req *http.Request
timeoutSet bool
timeout time.Duration
didCommonHeaders bool
headerMD metadata.MD
closeOnce sync.Once
closedCh chan struct{} // closed on Close
// writes is a channel of code to run serialized in the
// ServeHTTP (HandleStreams) goroutine. The channel is closed
// when WriteStatus is called.
writes chan func()
}
func (ht *serverHandlerTransport) Close() error {
ht.closeOnce.Do(ht.closeCloseChanOnce)
return nil
}
func (ht *serverHandlerTransport) closeCloseChanOnce() { close(ht.closedCh) }
func (ht *serverHandlerTransport) RemoteAddr() net.Addr { return strAddr(ht.req.RemoteAddr) }
// strAddr is a net.Addr backed by either a TCP "ip:port" string, or
// the empty string if unknown.
type strAddr string
func (a strAddr) Network() string {
if a != "" {
// Per the documentation on net/http.Request.RemoteAddr, if this is
// set, it's set to the IP:port of the peer (hence, TCP):
// https://golang.org/pkg/net/http/#Request
//
// If we want to support Unix sockets later, we can
// add our own grpc-specific convention within the
// grpc codebase to set RemoteAddr to a different
// format, or probably better: we can attach it to the
// context and use that from serverHandlerTransport.RemoteAddr.
return "tcp"
}
return ""
}
func (a strAddr) String() string { return string(a) }
// do runs fn in the ServeHTTP goroutine.
func (ht *serverHandlerTransport) do(fn func()) error {
// Avoid a panic writing to closed channel. Imperfect but maybe good enough.
select {
case <-ht.closedCh:
return ErrConnClosing
default:
select {
case ht.writes <- fn:
return nil
case <-ht.closedCh:
return ErrConnClosing
}
}
}
func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) error {
err := ht.do(func() {
ht.writeCommonHeaders(s)
// And flush, in case no header or body has been sent yet.
// This forces a separation of headers and trailers if this is the
// first call (for example, in end2end tests's TestNoService).
ht.rw.(http.Flusher).Flush()
h := ht.rw.Header()
h.Set("Grpc-Status", fmt.Sprintf("%d", st.Code()))
if m := st.Message(); m != "" {
h.Set("Grpc-Message", encodeGrpcMessage(m))
}
// TODO: Support Grpc-Status-Details-Bin
if md := s.Trailer(); len(md) > 0 {
for k, vv := range md {
// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
if isReservedHeader(k) {
continue
}
for _, v := range vv {
// http2 ResponseWriter mechanism to send undeclared Trailers after
// the headers have possibly been written.
h.Add(http2.TrailerPrefix+k, encodeMetadataHeader(k, v))
}
}
}
})
close(ht.writes)
return err
}
// writeCommonHeaders sets common headers on the first write
// call (Write, WriteHeader, or WriteStatus).
func (ht *serverHandlerTransport) writeCommonHeaders(s *Stream) {
if ht.didCommonHeaders {
return
}
ht.didCommonHeaders = true
h := ht.rw.Header()
h["Date"] = nil // suppress Date to make tests happy; TODO: restore
h.Set("Content-Type", "application/grpc")
// Predeclare trailers we'll set later in WriteStatus (after the body).
// This is a SHOULD in the HTTP RFC, and the way you add (known)
// Trailers per the net/http.ResponseWriter contract.
// See https://golang.org/pkg/net/http/#ResponseWriter
// and https://golang.org/pkg/net/http/#example_ResponseWriter_trailers
h.Add("Trailer", "Grpc-Status")
h.Add("Trailer", "Grpc-Message")
// TODO: Support Grpc-Status-Details-Bin
if s.sendCompress != "" {
h.Set("Grpc-Encoding", s.sendCompress)
}
}
func (ht *serverHandlerTransport) Write(s *Stream, data []byte, opts *Options) error {
return ht.do(func() {
ht.writeCommonHeaders(s)
ht.rw.Write(data)
if !opts.Delay {
ht.rw.(http.Flusher).Flush()
}
})
}
func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
return ht.do(func() {
ht.writeCommonHeaders(s)
h := ht.rw.Header()
for k, vv := range md {
// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
if isReservedHeader(k) {
continue
}
for _, v := range vv {
v = encodeMetadataHeader(k, v)
h.Add(k, v)
}
}
ht.rw.WriteHeader(200)
ht.rw.(http.Flusher).Flush()
})
}
func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) {
// With this transport type there will be exactly 1 stream: this HTTP request.
var ctx context.Context
var cancel context.CancelFunc
if ht.timeoutSet {
ctx, cancel = context.WithTimeout(context.Background(), ht.timeout)
} else {
ctx, cancel = context.WithCancel(context.Background())
}
// requestOver is closed when either the request's context is done
// or the status has been written via WriteStatus.
requestOver := make(chan struct{})
// clientGone receives a single value if peer is gone, either
// because the underlying connection is dead or because the
// peer sends an http2 RST_STREAM.
clientGone := ht.rw.(http.CloseNotifier).CloseNotify()
go func() {
select {
case <-requestOver:
return
case <-ht.closedCh:
case <-clientGone:
}
cancel()
}()
req := ht.req
s := &Stream{
id: 0, // irrelevant
requestRead: func(int) {},
cancel: cancel,
buf: newRecvBuffer(),
st: ht,
method: req.URL.Path,
recvCompress: req.Header.Get("grpc-encoding"),
}
pr := &peer.Peer{
Addr: ht.RemoteAddr(),
}
if req.TLS != nil {
pr.AuthInfo = credentials.TLSInfo{State: *req.TLS}
}
ctx = metadata.NewIncomingContext(ctx, ht.headerMD)
ctx = peer.NewContext(ctx, pr)
s.ctx = newContextWithStream(ctx, s)
s.trReader = &transportReader{
reader: &recvBufferReader{ctx: s.ctx, recv: s.buf},
windowHandler: func(int) {},
}
// readerDone is closed when the Body.Read-ing goroutine exits.
readerDone := make(chan struct{})
go func() {
defer close(readerDone)
// TODO: minimize garbage, optimize recvBuffer code/ownership
const readSize = 8196
for buf := make([]byte, readSize); ; {
n, err := req.Body.Read(buf)
if n > 0 {
s.buf.put(recvMsg{data: buf[:n:n]})
buf = buf[n:]
}
if err != nil {
s.buf.put(recvMsg{err: mapRecvMsgError(err)})
return
}
if len(buf) == 0 {
buf = make([]byte, readSize)
}
}
}()
// startStream is provided by the *grpc.Server's serveStreams.
// It starts a goroutine serving s and exits immediately.
// The goroutine that is started is the one that then calls
// into ht, calling WriteHeader, Write, WriteStatus, Close, etc.
startStream(s)
ht.runStream()
close(requestOver)
// Wait for reading goroutine to finish.
req.Body.Close()
<-readerDone
}
func (ht *serverHandlerTransport) runStream() {
for {
select {
case fn, ok := <-ht.writes:
if !ok {
return
}
fn()
case <-ht.closedCh:
return
}
}
}
func (ht *serverHandlerTransport) Drain() {
panic("Drain() is not implemented")
}
// mapRecvMsgError returns the non-nil err into the appropriate
// error value as expected by callers of *grpc.parser.recvMsg.
// In particular, in can only be:
// * io.EOF
// * io.ErrUnexpectedEOF
// * of type transport.ConnectionError
// * of type transport.StreamError
func mapRecvMsgError(err error) error {
if err == io.EOF || err == io.ErrUnexpectedEOF {
return err
}
if se, ok := err.(http2.StreamError); ok {
if code, ok := http2ErrConvTab[se.Code]; ok {
return StreamError{
Code: code,
Desc: se.Error(),
}
}
}
return connectionErrorf(true, err, err.Error())
}
|