Holger Hildebrandt | fa07499 | 2020-03-27 15:42:06 +0000 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2016 gRPC authors. |
| 4 | * |
| 5 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | * you may not use this file except in compliance with the License. |
| 7 | * You may obtain a copy of the License at |
| 8 | * |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | * |
| 11 | * Unless required by applicable law or agreed to in writing, software |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | * See the License for the specific language governing permissions and |
| 15 | * limitations under the License. |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | // This file is the implementation of a gRPC server using HTTP/2 which |
| 20 | // uses the standard Go http2 Server implementation (via the |
| 21 | // http.Handler interface), rather than speaking low-level HTTP/2 |
| 22 | // frames itself. It is the implementation of *grpc.Server.ServeHTTP. |
| 23 | |
| 24 | package transport |
| 25 | |
| 26 | import ( |
| 27 | "bytes" |
| 28 | "context" |
| 29 | "errors" |
| 30 | "fmt" |
| 31 | "io" |
| 32 | "net" |
| 33 | "net/http" |
| 34 | "strings" |
| 35 | "sync" |
| 36 | "time" |
| 37 | |
| 38 | "github.com/golang/protobuf/proto" |
| 39 | "golang.org/x/net/http2" |
| 40 | "google.golang.org/grpc/codes" |
| 41 | "google.golang.org/grpc/credentials" |
| 42 | "google.golang.org/grpc/metadata" |
| 43 | "google.golang.org/grpc/peer" |
| 44 | "google.golang.org/grpc/stats" |
| 45 | "google.golang.org/grpc/status" |
| 46 | ) |
| 47 | |
| 48 | // NewServerHandlerTransport returns a ServerTransport handling gRPC |
| 49 | // from inside an http.Handler. It requires that the http Server |
| 50 | // supports HTTP/2. |
| 51 | func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request, stats stats.Handler) (ServerTransport, error) { |
| 52 | if r.ProtoMajor != 2 { |
| 53 | return nil, errors.New("gRPC requires HTTP/2") |
| 54 | } |
| 55 | if r.Method != "POST" { |
| 56 | return nil, errors.New("invalid gRPC request method") |
| 57 | } |
| 58 | contentType := r.Header.Get("Content-Type") |
| 59 | // TODO: do we assume contentType is lowercase? we did before |
| 60 | contentSubtype, validContentType := contentSubtype(contentType) |
| 61 | if !validContentType { |
| 62 | return nil, errors.New("invalid gRPC request content-type") |
| 63 | } |
| 64 | if _, ok := w.(http.Flusher); !ok { |
| 65 | return nil, errors.New("gRPC requires a ResponseWriter supporting http.Flusher") |
| 66 | } |
| 67 | |
| 68 | st := &serverHandlerTransport{ |
| 69 | rw: w, |
| 70 | req: r, |
| 71 | closedCh: make(chan struct{}), |
| 72 | writes: make(chan func()), |
| 73 | contentType: contentType, |
| 74 | contentSubtype: contentSubtype, |
| 75 | stats: stats, |
| 76 | } |
| 77 | |
| 78 | if v := r.Header.Get("grpc-timeout"); v != "" { |
| 79 | to, err := decodeTimeout(v) |
| 80 | if err != nil { |
| 81 | return nil, status.Errorf(codes.Internal, "malformed time-out: %v", err) |
| 82 | } |
| 83 | st.timeoutSet = true |
| 84 | st.timeout = to |
| 85 | } |
| 86 | |
| 87 | metakv := []string{"content-type", contentType} |
| 88 | if r.Host != "" { |
| 89 | metakv = append(metakv, ":authority", r.Host) |
| 90 | } |
| 91 | for k, vv := range r.Header { |
| 92 | k = strings.ToLower(k) |
| 93 | if isReservedHeader(k) && !isWhitelistedHeader(k) { |
| 94 | continue |
| 95 | } |
| 96 | for _, v := range vv { |
| 97 | v, err := decodeMetadataHeader(k, v) |
| 98 | if err != nil { |
| 99 | return nil, status.Errorf(codes.Internal, "malformed binary metadata: %v", err) |
| 100 | } |
| 101 | metakv = append(metakv, k, v) |
| 102 | } |
| 103 | } |
| 104 | st.headerMD = metadata.Pairs(metakv...) |
| 105 | |
| 106 | return st, nil |
| 107 | } |
| 108 | |
| 109 | // serverHandlerTransport is an implementation of ServerTransport |
| 110 | // which replies to exactly one gRPC request (exactly one HTTP request), |
| 111 | // using the net/http.Handler interface. This http.Handler is guaranteed |
| 112 | // at this point to be speaking over HTTP/2, so it's able to speak valid |
| 113 | // gRPC. |
| 114 | type serverHandlerTransport struct { |
| 115 | rw http.ResponseWriter |
| 116 | req *http.Request |
| 117 | timeoutSet bool |
| 118 | timeout time.Duration |
| 119 | didCommonHeaders bool |
| 120 | |
| 121 | headerMD metadata.MD |
| 122 | |
| 123 | closeOnce sync.Once |
| 124 | closedCh chan struct{} // closed on Close |
| 125 | |
| 126 | // writes is a channel of code to run serialized in the |
| 127 | // ServeHTTP (HandleStreams) goroutine. The channel is closed |
| 128 | // when WriteStatus is called. |
| 129 | writes chan func() |
| 130 | |
| 131 | // block concurrent WriteStatus calls |
| 132 | // e.g. grpc/(*serverStream).SendMsg/RecvMsg |
| 133 | writeStatusMu sync.Mutex |
| 134 | |
| 135 | // we just mirror the request content-type |
| 136 | contentType string |
| 137 | // we store both contentType and contentSubtype so we don't keep recreating them |
| 138 | // TODO make sure this is consistent across handler_server and http2_server |
| 139 | contentSubtype string |
| 140 | |
| 141 | stats stats.Handler |
| 142 | } |
| 143 | |
| 144 | func (ht *serverHandlerTransport) Close() error { |
| 145 | ht.closeOnce.Do(ht.closeCloseChanOnce) |
| 146 | return nil |
| 147 | } |
| 148 | |
| 149 | func (ht *serverHandlerTransport) closeCloseChanOnce() { close(ht.closedCh) } |
| 150 | |
| 151 | func (ht *serverHandlerTransport) RemoteAddr() net.Addr { return strAddr(ht.req.RemoteAddr) } |
| 152 | |
| 153 | // strAddr is a net.Addr backed by either a TCP "ip:port" string, or |
| 154 | // the empty string if unknown. |
| 155 | type strAddr string |
| 156 | |
| 157 | func (a strAddr) Network() string { |
| 158 | if a != "" { |
| 159 | // Per the documentation on net/http.Request.RemoteAddr, if this is |
| 160 | // set, it's set to the IP:port of the peer (hence, TCP): |
| 161 | // https://golang.org/pkg/net/http/#Request |
| 162 | // |
| 163 | // If we want to support Unix sockets later, we can |
| 164 | // add our own grpc-specific convention within the |
| 165 | // grpc codebase to set RemoteAddr to a different |
| 166 | // format, or probably better: we can attach it to the |
| 167 | // context and use that from serverHandlerTransport.RemoteAddr. |
| 168 | return "tcp" |
| 169 | } |
| 170 | return "" |
| 171 | } |
| 172 | |
| 173 | func (a strAddr) String() string { return string(a) } |
| 174 | |
| 175 | // do runs fn in the ServeHTTP goroutine. |
| 176 | func (ht *serverHandlerTransport) do(fn func()) error { |
| 177 | select { |
| 178 | case <-ht.closedCh: |
| 179 | return ErrConnClosing |
| 180 | case ht.writes <- fn: |
| 181 | return nil |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | func (ht *serverHandlerTransport) WriteStatus(s *Stream, st *status.Status) error { |
| 186 | ht.writeStatusMu.Lock() |
| 187 | defer ht.writeStatusMu.Unlock() |
| 188 | |
| 189 | err := ht.do(func() { |
| 190 | ht.writeCommonHeaders(s) |
| 191 | |
| 192 | // And flush, in case no header or body has been sent yet. |
| 193 | // This forces a separation of headers and trailers if this is the |
| 194 | // first call (for example, in end2end tests's TestNoService). |
| 195 | ht.rw.(http.Flusher).Flush() |
| 196 | |
| 197 | h := ht.rw.Header() |
| 198 | h.Set("Grpc-Status", fmt.Sprintf("%d", st.Code())) |
| 199 | if m := st.Message(); m != "" { |
| 200 | h.Set("Grpc-Message", encodeGrpcMessage(m)) |
| 201 | } |
| 202 | |
| 203 | if p := st.Proto(); p != nil && len(p.Details) > 0 { |
| 204 | stBytes, err := proto.Marshal(p) |
| 205 | if err != nil { |
| 206 | // TODO: return error instead, when callers are able to handle it. |
| 207 | panic(err) |
| 208 | } |
| 209 | |
| 210 | h.Set("Grpc-Status-Details-Bin", encodeBinHeader(stBytes)) |
| 211 | } |
| 212 | |
| 213 | if md := s.Trailer(); len(md) > 0 { |
| 214 | for k, vv := range md { |
| 215 | // Clients don't tolerate reading restricted headers after some non restricted ones were sent. |
| 216 | if isReservedHeader(k) { |
| 217 | continue |
| 218 | } |
| 219 | for _, v := range vv { |
| 220 | // http2 ResponseWriter mechanism to send undeclared Trailers after |
| 221 | // the headers have possibly been written. |
| 222 | h.Add(http2.TrailerPrefix+k, encodeMetadataHeader(k, v)) |
| 223 | } |
| 224 | } |
| 225 | } |
| 226 | }) |
| 227 | |
| 228 | if err == nil { // transport has not been closed |
| 229 | if ht.stats != nil { |
| 230 | ht.stats.HandleRPC(s.Context(), &stats.OutTrailer{}) |
| 231 | } |
| 232 | } |
| 233 | ht.Close() |
| 234 | return err |
| 235 | } |
| 236 | |
| 237 | // writeCommonHeaders sets common headers on the first write |
| 238 | // call (Write, WriteHeader, or WriteStatus). |
| 239 | func (ht *serverHandlerTransport) writeCommonHeaders(s *Stream) { |
| 240 | if ht.didCommonHeaders { |
| 241 | return |
| 242 | } |
| 243 | ht.didCommonHeaders = true |
| 244 | |
| 245 | h := ht.rw.Header() |
| 246 | h["Date"] = nil // suppress Date to make tests happy; TODO: restore |
| 247 | h.Set("Content-Type", ht.contentType) |
| 248 | |
| 249 | // Predeclare trailers we'll set later in WriteStatus (after the body). |
| 250 | // This is a SHOULD in the HTTP RFC, and the way you add (known) |
| 251 | // Trailers per the net/http.ResponseWriter contract. |
| 252 | // See https://golang.org/pkg/net/http/#ResponseWriter |
| 253 | // and https://golang.org/pkg/net/http/#example_ResponseWriter_trailers |
| 254 | h.Add("Trailer", "Grpc-Status") |
| 255 | h.Add("Trailer", "Grpc-Message") |
| 256 | h.Add("Trailer", "Grpc-Status-Details-Bin") |
| 257 | |
| 258 | if s.sendCompress != "" { |
| 259 | h.Set("Grpc-Encoding", s.sendCompress) |
| 260 | } |
| 261 | } |
| 262 | |
| 263 | func (ht *serverHandlerTransport) Write(s *Stream, hdr []byte, data []byte, opts *Options) error { |
| 264 | return ht.do(func() { |
| 265 | ht.writeCommonHeaders(s) |
| 266 | ht.rw.Write(hdr) |
| 267 | ht.rw.Write(data) |
| 268 | ht.rw.(http.Flusher).Flush() |
| 269 | }) |
| 270 | } |
| 271 | |
| 272 | func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error { |
| 273 | err := ht.do(func() { |
| 274 | ht.writeCommonHeaders(s) |
| 275 | h := ht.rw.Header() |
| 276 | for k, vv := range md { |
| 277 | // Clients don't tolerate reading restricted headers after some non restricted ones were sent. |
| 278 | if isReservedHeader(k) { |
| 279 | continue |
| 280 | } |
| 281 | for _, v := range vv { |
| 282 | v = encodeMetadataHeader(k, v) |
| 283 | h.Add(k, v) |
| 284 | } |
| 285 | } |
| 286 | ht.rw.WriteHeader(200) |
| 287 | ht.rw.(http.Flusher).Flush() |
| 288 | }) |
| 289 | |
| 290 | if err == nil { |
| 291 | if ht.stats != nil { |
| 292 | ht.stats.HandleRPC(s.Context(), &stats.OutHeader{}) |
| 293 | } |
| 294 | } |
| 295 | return err |
| 296 | } |
| 297 | |
| 298 | func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) { |
| 299 | // With this transport type there will be exactly 1 stream: this HTTP request. |
| 300 | |
| 301 | ctx := ht.req.Context() |
| 302 | var cancel context.CancelFunc |
| 303 | if ht.timeoutSet { |
| 304 | ctx, cancel = context.WithTimeout(ctx, ht.timeout) |
| 305 | } else { |
| 306 | ctx, cancel = context.WithCancel(ctx) |
| 307 | } |
| 308 | |
| 309 | // requestOver is closed when the status has been written via WriteStatus. |
| 310 | requestOver := make(chan struct{}) |
| 311 | go func() { |
| 312 | select { |
| 313 | case <-requestOver: |
| 314 | case <-ht.closedCh: |
| 315 | case <-ht.req.Context().Done(): |
| 316 | } |
| 317 | cancel() |
| 318 | ht.Close() |
| 319 | }() |
| 320 | |
| 321 | req := ht.req |
| 322 | |
| 323 | s := &Stream{ |
| 324 | id: 0, // irrelevant |
| 325 | requestRead: func(int) {}, |
| 326 | cancel: cancel, |
| 327 | buf: newRecvBuffer(), |
| 328 | st: ht, |
| 329 | method: req.URL.Path, |
| 330 | recvCompress: req.Header.Get("grpc-encoding"), |
| 331 | contentSubtype: ht.contentSubtype, |
| 332 | } |
| 333 | pr := &peer.Peer{ |
| 334 | Addr: ht.RemoteAddr(), |
| 335 | } |
| 336 | if req.TLS != nil { |
| 337 | pr.AuthInfo = credentials.TLSInfo{State: *req.TLS} |
| 338 | } |
| 339 | ctx = metadata.NewIncomingContext(ctx, ht.headerMD) |
| 340 | s.ctx = peer.NewContext(ctx, pr) |
| 341 | if ht.stats != nil { |
| 342 | s.ctx = ht.stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method}) |
| 343 | inHeader := &stats.InHeader{ |
| 344 | FullMethod: s.method, |
| 345 | RemoteAddr: ht.RemoteAddr(), |
| 346 | Compression: s.recvCompress, |
| 347 | } |
| 348 | ht.stats.HandleRPC(s.ctx, inHeader) |
| 349 | } |
| 350 | s.trReader = &transportReader{ |
| 351 | reader: &recvBufferReader{ctx: s.ctx, ctxDone: s.ctx.Done(), recv: s.buf, freeBuffer: func(*bytes.Buffer) {}}, |
| 352 | windowHandler: func(int) {}, |
| 353 | } |
| 354 | |
| 355 | // readerDone is closed when the Body.Read-ing goroutine exits. |
| 356 | readerDone := make(chan struct{}) |
| 357 | go func() { |
| 358 | defer close(readerDone) |
| 359 | |
| 360 | // TODO: minimize garbage, optimize recvBuffer code/ownership |
| 361 | const readSize = 8196 |
| 362 | for buf := make([]byte, readSize); ; { |
| 363 | n, err := req.Body.Read(buf) |
| 364 | if n > 0 { |
| 365 | s.buf.put(recvMsg{buffer: bytes.NewBuffer(buf[:n:n])}) |
| 366 | buf = buf[n:] |
| 367 | } |
| 368 | if err != nil { |
| 369 | s.buf.put(recvMsg{err: mapRecvMsgError(err)}) |
| 370 | return |
| 371 | } |
| 372 | if len(buf) == 0 { |
| 373 | buf = make([]byte, readSize) |
| 374 | } |
| 375 | } |
| 376 | }() |
| 377 | |
| 378 | // startStream is provided by the *grpc.Server's serveStreams. |
| 379 | // It starts a goroutine serving s and exits immediately. |
| 380 | // The goroutine that is started is the one that then calls |
| 381 | // into ht, calling WriteHeader, Write, WriteStatus, Close, etc. |
| 382 | startStream(s) |
| 383 | |
| 384 | ht.runStream() |
| 385 | close(requestOver) |
| 386 | |
| 387 | // Wait for reading goroutine to finish. |
| 388 | req.Body.Close() |
| 389 | <-readerDone |
| 390 | } |
| 391 | |
| 392 | func (ht *serverHandlerTransport) runStream() { |
| 393 | for { |
| 394 | select { |
| 395 | case fn := <-ht.writes: |
| 396 | fn() |
| 397 | case <-ht.closedCh: |
| 398 | return |
| 399 | } |
| 400 | } |
| 401 | } |
| 402 | |
| 403 | func (ht *serverHandlerTransport) IncrMsgSent() {} |
| 404 | |
| 405 | func (ht *serverHandlerTransport) IncrMsgRecv() {} |
| 406 | |
| 407 | func (ht *serverHandlerTransport) Drain() { |
| 408 | panic("Drain() is not implemented") |
| 409 | } |
| 410 | |
| 411 | // mapRecvMsgError returns the non-nil err into the appropriate |
| 412 | // error value as expected by callers of *grpc.parser.recvMsg. |
| 413 | // In particular, in can only be: |
| 414 | // * io.EOF |
| 415 | // * io.ErrUnexpectedEOF |
| 416 | // * of type transport.ConnectionError |
| 417 | // * an error from the status package |
| 418 | func mapRecvMsgError(err error) error { |
| 419 | if err == io.EOF || err == io.ErrUnexpectedEOF { |
| 420 | return err |
| 421 | } |
| 422 | if se, ok := err.(http2.StreamError); ok { |
| 423 | if code, ok := http2ErrConvTab[se.Code]; ok { |
| 424 | return status.Error(code, se.Error()) |
| 425 | } |
| 426 | } |
| 427 | if strings.Contains(err.Error(), "body closed by handler") { |
| 428 | return status.Error(codes.Canceled, err.Error()) |
| 429 | } |
| 430 | return connectionErrorf(true, err, err.Error()) |
| 431 | } |