Zack Williams | e940c7a | 2019-08-21 14:25:39 -0700 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright 2014 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 | // Package transport defines and implements message oriented communication |
| 20 | // channel to complete various transactions (e.g., an RPC). It is meant for |
| 21 | // grpc-internal usage and is not intended to be imported directly by users. |
| 22 | package transport |
| 23 | |
| 24 | import ( |
| 25 | "context" |
| 26 | "errors" |
| 27 | "fmt" |
| 28 | "io" |
| 29 | "net" |
| 30 | "sync" |
| 31 | "sync/atomic" |
| 32 | |
| 33 | "google.golang.org/grpc/codes" |
| 34 | "google.golang.org/grpc/credentials" |
| 35 | "google.golang.org/grpc/keepalive" |
| 36 | "google.golang.org/grpc/metadata" |
| 37 | "google.golang.org/grpc/stats" |
| 38 | "google.golang.org/grpc/status" |
| 39 | "google.golang.org/grpc/tap" |
| 40 | ) |
| 41 | |
| 42 | // recvMsg represents the received msg from the transport. All transport |
| 43 | // protocol specific info has been removed. |
| 44 | type recvMsg struct { |
| 45 | data []byte |
| 46 | // nil: received some data |
| 47 | // io.EOF: stream is completed. data is nil. |
| 48 | // other non-nil error: transport failure. data is nil. |
| 49 | err error |
| 50 | } |
| 51 | |
| 52 | // recvBuffer is an unbounded channel of recvMsg structs. |
| 53 | // Note recvBuffer differs from controlBuffer only in that recvBuffer |
| 54 | // holds a channel of only recvMsg structs instead of objects implementing "item" interface. |
| 55 | // recvBuffer is written to much more often than |
| 56 | // controlBuffer and using strict recvMsg structs helps avoid allocation in "recvBuffer.put" |
| 57 | type recvBuffer struct { |
| 58 | c chan recvMsg |
| 59 | mu sync.Mutex |
| 60 | backlog []recvMsg |
| 61 | err error |
| 62 | } |
| 63 | |
| 64 | func newRecvBuffer() *recvBuffer { |
| 65 | b := &recvBuffer{ |
| 66 | c: make(chan recvMsg, 1), |
| 67 | } |
| 68 | return b |
| 69 | } |
| 70 | |
| 71 | func (b *recvBuffer) put(r recvMsg) { |
| 72 | b.mu.Lock() |
| 73 | if b.err != nil { |
| 74 | b.mu.Unlock() |
| 75 | // An error had occurred earlier, don't accept more |
| 76 | // data or errors. |
| 77 | return |
| 78 | } |
| 79 | b.err = r.err |
| 80 | if len(b.backlog) == 0 { |
| 81 | select { |
| 82 | case b.c <- r: |
| 83 | b.mu.Unlock() |
| 84 | return |
| 85 | default: |
| 86 | } |
| 87 | } |
| 88 | b.backlog = append(b.backlog, r) |
| 89 | b.mu.Unlock() |
| 90 | } |
| 91 | |
| 92 | func (b *recvBuffer) load() { |
| 93 | b.mu.Lock() |
| 94 | if len(b.backlog) > 0 { |
| 95 | select { |
| 96 | case b.c <- b.backlog[0]: |
| 97 | b.backlog[0] = recvMsg{} |
| 98 | b.backlog = b.backlog[1:] |
| 99 | default: |
| 100 | } |
| 101 | } |
| 102 | b.mu.Unlock() |
| 103 | } |
| 104 | |
| 105 | // get returns the channel that receives a recvMsg in the buffer. |
| 106 | // |
| 107 | // Upon receipt of a recvMsg, the caller should call load to send another |
| 108 | // recvMsg onto the channel if there is any. |
| 109 | func (b *recvBuffer) get() <-chan recvMsg { |
| 110 | return b.c |
| 111 | } |
| 112 | |
| 113 | // recvBufferReader implements io.Reader interface to read the data from |
| 114 | // recvBuffer. |
| 115 | type recvBufferReader struct { |
| 116 | closeStream func(error) // Closes the client transport stream with the given error and nil trailer metadata. |
| 117 | ctx context.Context |
| 118 | ctxDone <-chan struct{} // cache of ctx.Done() (for performance). |
| 119 | recv *recvBuffer |
| 120 | last []byte // Stores the remaining data in the previous calls. |
| 121 | err error |
| 122 | } |
| 123 | |
| 124 | // Read reads the next len(p) bytes from last. If last is drained, it tries to |
| 125 | // read additional data from recv. It blocks if there no additional data available |
| 126 | // in recv. If Read returns any non-nil error, it will continue to return that error. |
| 127 | func (r *recvBufferReader) Read(p []byte) (n int, err error) { |
| 128 | if r.err != nil { |
| 129 | return 0, r.err |
| 130 | } |
| 131 | if r.last != nil && len(r.last) > 0 { |
| 132 | // Read remaining data left in last call. |
| 133 | copied := copy(p, r.last) |
| 134 | r.last = r.last[copied:] |
| 135 | return copied, nil |
| 136 | } |
| 137 | if r.closeStream != nil { |
| 138 | n, r.err = r.readClient(p) |
| 139 | } else { |
| 140 | n, r.err = r.read(p) |
| 141 | } |
| 142 | return n, r.err |
| 143 | } |
| 144 | |
| 145 | func (r *recvBufferReader) read(p []byte) (n int, err error) { |
| 146 | select { |
| 147 | case <-r.ctxDone: |
| 148 | return 0, ContextErr(r.ctx.Err()) |
| 149 | case m := <-r.recv.get(): |
| 150 | return r.readAdditional(m, p) |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | func (r *recvBufferReader) readClient(p []byte) (n int, err error) { |
| 155 | // If the context is canceled, then closes the stream with nil metadata. |
| 156 | // closeStream writes its error parameter to r.recv as a recvMsg. |
| 157 | // r.readAdditional acts on that message and returns the necessary error. |
| 158 | select { |
| 159 | case <-r.ctxDone: |
| 160 | r.closeStream(ContextErr(r.ctx.Err())) |
| 161 | m := <-r.recv.get() |
| 162 | return r.readAdditional(m, p) |
| 163 | case m := <-r.recv.get(): |
| 164 | return r.readAdditional(m, p) |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | func (r *recvBufferReader) readAdditional(m recvMsg, p []byte) (n int, err error) { |
| 169 | r.recv.load() |
| 170 | if m.err != nil { |
| 171 | return 0, m.err |
| 172 | } |
| 173 | copied := copy(p, m.data) |
| 174 | r.last = m.data[copied:] |
| 175 | return copied, nil |
| 176 | } |
| 177 | |
| 178 | type streamState uint32 |
| 179 | |
| 180 | const ( |
| 181 | streamActive streamState = iota |
| 182 | streamWriteDone // EndStream sent |
| 183 | streamReadDone // EndStream received |
| 184 | streamDone // the entire stream is finished. |
| 185 | ) |
| 186 | |
| 187 | // Stream represents an RPC in the transport layer. |
| 188 | type Stream struct { |
| 189 | id uint32 |
| 190 | st ServerTransport // nil for client side Stream |
| 191 | ctx context.Context // the associated context of the stream |
| 192 | cancel context.CancelFunc // always nil for client side Stream |
| 193 | done chan struct{} // closed at the end of stream to unblock writers. On the client side. |
| 194 | ctxDone <-chan struct{} // same as done chan but for server side. Cache of ctx.Done() (for performance) |
| 195 | method string // the associated RPC method of the stream |
| 196 | recvCompress string |
| 197 | sendCompress string |
| 198 | buf *recvBuffer |
| 199 | trReader io.Reader |
| 200 | fc *inFlow |
| 201 | wq *writeQuota |
| 202 | |
| 203 | // Callback to state application's intentions to read data. This |
| 204 | // is used to adjust flow control, if needed. |
| 205 | requestRead func(int) |
| 206 | |
| 207 | headerChan chan struct{} // closed to indicate the end of header metadata. |
| 208 | headerDone uint32 // set when headerChan is closed. Used to avoid closing headerChan multiple times. |
| 209 | |
| 210 | // hdrMu protects header and trailer metadata on the server-side. |
| 211 | hdrMu sync.Mutex |
| 212 | // On client side, header keeps the received header metadata. |
| 213 | // |
| 214 | // On server side, header keeps the header set by SetHeader(). The complete |
| 215 | // header will merged into this after t.WriteHeader() is called. |
| 216 | header metadata.MD |
| 217 | trailer metadata.MD // the key-value map of trailer metadata. |
| 218 | |
| 219 | noHeaders bool // set if the client never received headers (set only after the stream is done). |
| 220 | |
| 221 | // On the server-side, headerSent is atomically set to 1 when the headers are sent out. |
| 222 | headerSent uint32 |
| 223 | |
| 224 | state streamState |
| 225 | |
| 226 | // On client-side it is the status error received from the server. |
| 227 | // On server-side it is unused. |
| 228 | status *status.Status |
| 229 | |
| 230 | bytesReceived uint32 // indicates whether any bytes have been received on this stream |
| 231 | unprocessed uint32 // set if the server sends a refused stream or GOAWAY including this stream |
| 232 | |
| 233 | // contentSubtype is the content-subtype for requests. |
| 234 | // this must be lowercase or the behavior is undefined. |
| 235 | contentSubtype string |
| 236 | } |
| 237 | |
| 238 | // isHeaderSent is only valid on the server-side. |
| 239 | func (s *Stream) isHeaderSent() bool { |
| 240 | return atomic.LoadUint32(&s.headerSent) == 1 |
| 241 | } |
| 242 | |
| 243 | // updateHeaderSent updates headerSent and returns true |
| 244 | // if it was alreay set. It is valid only on server-side. |
| 245 | func (s *Stream) updateHeaderSent() bool { |
| 246 | return atomic.SwapUint32(&s.headerSent, 1) == 1 |
| 247 | } |
| 248 | |
| 249 | func (s *Stream) swapState(st streamState) streamState { |
| 250 | return streamState(atomic.SwapUint32((*uint32)(&s.state), uint32(st))) |
| 251 | } |
| 252 | |
| 253 | func (s *Stream) compareAndSwapState(oldState, newState streamState) bool { |
| 254 | return atomic.CompareAndSwapUint32((*uint32)(&s.state), uint32(oldState), uint32(newState)) |
| 255 | } |
| 256 | |
| 257 | func (s *Stream) getState() streamState { |
| 258 | return streamState(atomic.LoadUint32((*uint32)(&s.state))) |
| 259 | } |
| 260 | |
| 261 | func (s *Stream) waitOnHeader() error { |
| 262 | if s.headerChan == nil { |
| 263 | // On the server headerChan is always nil since a stream originates |
| 264 | // only after having received headers. |
| 265 | return nil |
| 266 | } |
| 267 | select { |
| 268 | case <-s.ctx.Done(): |
| 269 | return ContextErr(s.ctx.Err()) |
| 270 | case <-s.headerChan: |
| 271 | return nil |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | // RecvCompress returns the compression algorithm applied to the inbound |
| 276 | // message. It is empty string if there is no compression applied. |
| 277 | func (s *Stream) RecvCompress() string { |
| 278 | if err := s.waitOnHeader(); err != nil { |
| 279 | return "" |
| 280 | } |
| 281 | return s.recvCompress |
| 282 | } |
| 283 | |
| 284 | // SetSendCompress sets the compression algorithm to the stream. |
| 285 | func (s *Stream) SetSendCompress(str string) { |
| 286 | s.sendCompress = str |
| 287 | } |
| 288 | |
| 289 | // Done returns a channel which is closed when it receives the final status |
| 290 | // from the server. |
| 291 | func (s *Stream) Done() <-chan struct{} { |
| 292 | return s.done |
| 293 | } |
| 294 | |
| 295 | // Header returns the header metadata of the stream. |
| 296 | // |
| 297 | // On client side, it acquires the key-value pairs of header metadata once it is |
| 298 | // available. It blocks until i) the metadata is ready or ii) there is no header |
| 299 | // metadata or iii) the stream is canceled/expired. |
| 300 | // |
| 301 | // On server side, it returns the out header after t.WriteHeader is called. |
| 302 | func (s *Stream) Header() (metadata.MD, error) { |
| 303 | if s.headerChan == nil && s.header != nil { |
| 304 | // On server side, return the header in stream. It will be the out |
| 305 | // header after t.WriteHeader is called. |
| 306 | return s.header.Copy(), nil |
| 307 | } |
| 308 | err := s.waitOnHeader() |
| 309 | // Even if the stream is closed, header is returned if available. |
| 310 | select { |
| 311 | case <-s.headerChan: |
| 312 | if s.header == nil { |
| 313 | return nil, nil |
| 314 | } |
| 315 | return s.header.Copy(), nil |
| 316 | default: |
| 317 | } |
| 318 | return nil, err |
| 319 | } |
| 320 | |
| 321 | // TrailersOnly blocks until a header or trailers-only frame is received and |
| 322 | // then returns true if the stream was trailers-only. If the stream ends |
| 323 | // before headers are received, returns true, nil. If a context error happens |
| 324 | // first, returns it as a status error. Client-side only. |
| 325 | func (s *Stream) TrailersOnly() (bool, error) { |
| 326 | err := s.waitOnHeader() |
| 327 | if err != nil { |
| 328 | return false, err |
| 329 | } |
| 330 | return s.noHeaders, nil |
| 331 | } |
| 332 | |
| 333 | // Trailer returns the cached trailer metedata. Note that if it is not called |
| 334 | // after the entire stream is done, it could return an empty MD. Client |
| 335 | // side only. |
| 336 | // It can be safely read only after stream has ended that is either read |
| 337 | // or write have returned io.EOF. |
| 338 | func (s *Stream) Trailer() metadata.MD { |
| 339 | c := s.trailer.Copy() |
| 340 | return c |
| 341 | } |
| 342 | |
| 343 | // ContentSubtype returns the content-subtype for a request. For example, a |
| 344 | // content-subtype of "proto" will result in a content-type of |
| 345 | // "application/grpc+proto". This will always be lowercase. See |
| 346 | // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for |
| 347 | // more details. |
| 348 | func (s *Stream) ContentSubtype() string { |
| 349 | return s.contentSubtype |
| 350 | } |
| 351 | |
| 352 | // Context returns the context of the stream. |
| 353 | func (s *Stream) Context() context.Context { |
| 354 | return s.ctx |
| 355 | } |
| 356 | |
| 357 | // Method returns the method for the stream. |
| 358 | func (s *Stream) Method() string { |
| 359 | return s.method |
| 360 | } |
| 361 | |
| 362 | // Status returns the status received from the server. |
| 363 | // Status can be read safely only after the stream has ended, |
| 364 | // that is, after Done() is closed. |
| 365 | func (s *Stream) Status() *status.Status { |
| 366 | return s.status |
| 367 | } |
| 368 | |
| 369 | // SetHeader sets the header metadata. This can be called multiple times. |
| 370 | // Server side only. |
| 371 | // This should not be called in parallel to other data writes. |
| 372 | func (s *Stream) SetHeader(md metadata.MD) error { |
| 373 | if md.Len() == 0 { |
| 374 | return nil |
| 375 | } |
| 376 | if s.isHeaderSent() || s.getState() == streamDone { |
| 377 | return ErrIllegalHeaderWrite |
| 378 | } |
| 379 | s.hdrMu.Lock() |
| 380 | s.header = metadata.Join(s.header, md) |
| 381 | s.hdrMu.Unlock() |
| 382 | return nil |
| 383 | } |
| 384 | |
| 385 | // SendHeader sends the given header metadata. The given metadata is |
| 386 | // combined with any metadata set by previous calls to SetHeader and |
| 387 | // then written to the transport stream. |
| 388 | func (s *Stream) SendHeader(md metadata.MD) error { |
| 389 | return s.st.WriteHeader(s, md) |
| 390 | } |
| 391 | |
| 392 | // SetTrailer sets the trailer metadata which will be sent with the RPC status |
| 393 | // by the server. This can be called multiple times. Server side only. |
| 394 | // This should not be called parallel to other data writes. |
| 395 | func (s *Stream) SetTrailer(md metadata.MD) error { |
| 396 | if md.Len() == 0 { |
| 397 | return nil |
| 398 | } |
| 399 | if s.getState() == streamDone { |
| 400 | return ErrIllegalHeaderWrite |
| 401 | } |
| 402 | s.hdrMu.Lock() |
| 403 | s.trailer = metadata.Join(s.trailer, md) |
| 404 | s.hdrMu.Unlock() |
| 405 | return nil |
| 406 | } |
| 407 | |
| 408 | func (s *Stream) write(m recvMsg) { |
| 409 | s.buf.put(m) |
| 410 | } |
| 411 | |
| 412 | // Read reads all p bytes from the wire for this stream. |
| 413 | func (s *Stream) Read(p []byte) (n int, err error) { |
| 414 | // Don't request a read if there was an error earlier |
| 415 | if er := s.trReader.(*transportReader).er; er != nil { |
| 416 | return 0, er |
| 417 | } |
| 418 | s.requestRead(len(p)) |
| 419 | return io.ReadFull(s.trReader, p) |
| 420 | } |
| 421 | |
| 422 | // tranportReader reads all the data available for this Stream from the transport and |
| 423 | // passes them into the decoder, which converts them into a gRPC message stream. |
| 424 | // The error is io.EOF when the stream is done or another non-nil error if |
| 425 | // the stream broke. |
| 426 | type transportReader struct { |
| 427 | reader io.Reader |
| 428 | // The handler to control the window update procedure for both this |
| 429 | // particular stream and the associated transport. |
| 430 | windowHandler func(int) |
| 431 | er error |
| 432 | } |
| 433 | |
| 434 | func (t *transportReader) Read(p []byte) (n int, err error) { |
| 435 | n, err = t.reader.Read(p) |
| 436 | if err != nil { |
| 437 | t.er = err |
| 438 | return |
| 439 | } |
| 440 | t.windowHandler(n) |
| 441 | return |
| 442 | } |
| 443 | |
| 444 | // BytesReceived indicates whether any bytes have been received on this stream. |
| 445 | func (s *Stream) BytesReceived() bool { |
| 446 | return atomic.LoadUint32(&s.bytesReceived) == 1 |
| 447 | } |
| 448 | |
| 449 | // Unprocessed indicates whether the server did not process this stream -- |
| 450 | // i.e. it sent a refused stream or GOAWAY including this stream ID. |
| 451 | func (s *Stream) Unprocessed() bool { |
| 452 | return atomic.LoadUint32(&s.unprocessed) == 1 |
| 453 | } |
| 454 | |
| 455 | // GoString is implemented by Stream so context.String() won't |
| 456 | // race when printing %#v. |
| 457 | func (s *Stream) GoString() string { |
| 458 | return fmt.Sprintf("<stream: %p, %v>", s, s.method) |
| 459 | } |
| 460 | |
| 461 | // state of transport |
| 462 | type transportState int |
| 463 | |
| 464 | const ( |
| 465 | reachable transportState = iota |
| 466 | closing |
| 467 | draining |
| 468 | ) |
| 469 | |
| 470 | // ServerConfig consists of all the configurations to establish a server transport. |
| 471 | type ServerConfig struct { |
| 472 | MaxStreams uint32 |
| 473 | AuthInfo credentials.AuthInfo |
| 474 | InTapHandle tap.ServerInHandle |
| 475 | StatsHandler stats.Handler |
| 476 | KeepaliveParams keepalive.ServerParameters |
| 477 | KeepalivePolicy keepalive.EnforcementPolicy |
| 478 | InitialWindowSize int32 |
| 479 | InitialConnWindowSize int32 |
| 480 | WriteBufferSize int |
| 481 | ReadBufferSize int |
| 482 | ChannelzParentID int64 |
| 483 | MaxHeaderListSize *uint32 |
| 484 | } |
| 485 | |
| 486 | // NewServerTransport creates a ServerTransport with conn or non-nil error |
| 487 | // if it fails. |
| 488 | func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) { |
| 489 | return newHTTP2Server(conn, config) |
| 490 | } |
| 491 | |
| 492 | // ConnectOptions covers all relevant options for communicating with the server. |
| 493 | type ConnectOptions struct { |
| 494 | // UserAgent is the application user agent. |
| 495 | UserAgent string |
| 496 | // Dialer specifies how to dial a network address. |
| 497 | Dialer func(context.Context, string) (net.Conn, error) |
| 498 | // FailOnNonTempDialError specifies if gRPC fails on non-temporary dial errors. |
| 499 | FailOnNonTempDialError bool |
| 500 | // PerRPCCredentials stores the PerRPCCredentials required to issue RPCs. |
| 501 | PerRPCCredentials []credentials.PerRPCCredentials |
| 502 | // TransportCredentials stores the Authenticator required to setup a client |
| 503 | // connection. Only one of TransportCredentials and CredsBundle is non-nil. |
| 504 | TransportCredentials credentials.TransportCredentials |
| 505 | // CredsBundle is the credentials bundle to be used. Only one of |
| 506 | // TransportCredentials and CredsBundle is non-nil. |
| 507 | CredsBundle credentials.Bundle |
| 508 | // KeepaliveParams stores the keepalive parameters. |
| 509 | KeepaliveParams keepalive.ClientParameters |
| 510 | // StatsHandler stores the handler for stats. |
| 511 | StatsHandler stats.Handler |
| 512 | // InitialWindowSize sets the initial window size for a stream. |
| 513 | InitialWindowSize int32 |
| 514 | // InitialConnWindowSize sets the initial window size for a connection. |
| 515 | InitialConnWindowSize int32 |
| 516 | // WriteBufferSize sets the size of write buffer which in turn determines how much data can be batched before it's written on the wire. |
| 517 | WriteBufferSize int |
| 518 | // ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall. |
| 519 | ReadBufferSize int |
| 520 | // ChannelzParentID sets the addrConn id which initiate the creation of this client transport. |
| 521 | ChannelzParentID int64 |
| 522 | // MaxHeaderListSize sets the max (uncompressed) size of header list that is prepared to be received. |
| 523 | MaxHeaderListSize *uint32 |
| 524 | } |
| 525 | |
| 526 | // TargetInfo contains the information of the target such as network address and metadata. |
| 527 | type TargetInfo struct { |
| 528 | Addr string |
| 529 | Metadata interface{} |
| 530 | Authority string |
| 531 | } |
| 532 | |
| 533 | // NewClientTransport establishes the transport with the required ConnectOptions |
| 534 | // and returns it to the caller. |
| 535 | func NewClientTransport(connectCtx, ctx context.Context, target TargetInfo, opts ConnectOptions, onPrefaceReceipt func(), onGoAway func(GoAwayReason), onClose func()) (ClientTransport, error) { |
| 536 | return newHTTP2Client(connectCtx, ctx, target, opts, onPrefaceReceipt, onGoAway, onClose) |
| 537 | } |
| 538 | |
| 539 | // Options provides additional hints and information for message |
| 540 | // transmission. |
| 541 | type Options struct { |
| 542 | // Last indicates whether this write is the last piece for |
| 543 | // this stream. |
| 544 | Last bool |
| 545 | } |
| 546 | |
| 547 | // CallHdr carries the information of a particular RPC. |
| 548 | type CallHdr struct { |
| 549 | // Host specifies the peer's host. |
| 550 | Host string |
| 551 | |
| 552 | // Method specifies the operation to perform. |
| 553 | Method string |
| 554 | |
| 555 | // SendCompress specifies the compression algorithm applied on |
| 556 | // outbound message. |
| 557 | SendCompress string |
| 558 | |
| 559 | // Creds specifies credentials.PerRPCCredentials for a call. |
| 560 | Creds credentials.PerRPCCredentials |
| 561 | |
| 562 | // ContentSubtype specifies the content-subtype for a request. For example, a |
| 563 | // content-subtype of "proto" will result in a content-type of |
| 564 | // "application/grpc+proto". The value of ContentSubtype must be all |
| 565 | // lowercase, otherwise the behavior is undefined. See |
| 566 | // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests |
| 567 | // for more details. |
| 568 | ContentSubtype string |
| 569 | |
| 570 | PreviousAttempts int // value of grpc-previous-rpc-attempts header to set |
| 571 | } |
| 572 | |
| 573 | // ClientTransport is the common interface for all gRPC client-side transport |
| 574 | // implementations. |
| 575 | type ClientTransport interface { |
| 576 | // Close tears down this transport. Once it returns, the transport |
| 577 | // should not be accessed any more. The caller must make sure this |
| 578 | // is called only once. |
| 579 | Close() error |
| 580 | |
| 581 | // GracefulClose starts to tear down the transport: the transport will stop |
| 582 | // accepting new RPCs and NewStream will return error. Once all streams are |
| 583 | // finished, the transport will close. |
| 584 | // |
| 585 | // It does not block. |
| 586 | GracefulClose() |
| 587 | |
| 588 | // Write sends the data for the given stream. A nil stream indicates |
| 589 | // the write is to be performed on the transport as a whole. |
| 590 | Write(s *Stream, hdr []byte, data []byte, opts *Options) error |
| 591 | |
| 592 | // NewStream creates a Stream for an RPC. |
| 593 | NewStream(ctx context.Context, callHdr *CallHdr) (*Stream, error) |
| 594 | |
| 595 | // CloseStream clears the footprint of a stream when the stream is |
| 596 | // not needed any more. The err indicates the error incurred when |
| 597 | // CloseStream is called. Must be called when a stream is finished |
| 598 | // unless the associated transport is closing. |
| 599 | CloseStream(stream *Stream, err error) |
| 600 | |
| 601 | // Error returns a channel that is closed when some I/O error |
| 602 | // happens. Typically the caller should have a goroutine to monitor |
| 603 | // this in order to take action (e.g., close the current transport |
| 604 | // and create a new one) in error case. It should not return nil |
| 605 | // once the transport is initiated. |
| 606 | Error() <-chan struct{} |
| 607 | |
| 608 | // GoAway returns a channel that is closed when ClientTransport |
| 609 | // receives the draining signal from the server (e.g., GOAWAY frame in |
| 610 | // HTTP/2). |
| 611 | GoAway() <-chan struct{} |
| 612 | |
| 613 | // GetGoAwayReason returns the reason why GoAway frame was received. |
| 614 | GetGoAwayReason() GoAwayReason |
| 615 | |
| 616 | // RemoteAddr returns the remote network address. |
| 617 | RemoteAddr() net.Addr |
| 618 | |
| 619 | // IncrMsgSent increments the number of message sent through this transport. |
| 620 | IncrMsgSent() |
| 621 | |
| 622 | // IncrMsgRecv increments the number of message received through this transport. |
| 623 | IncrMsgRecv() |
| 624 | } |
| 625 | |
| 626 | // ServerTransport is the common interface for all gRPC server-side transport |
| 627 | // implementations. |
| 628 | // |
| 629 | // Methods may be called concurrently from multiple goroutines, but |
| 630 | // Write methods for a given Stream will be called serially. |
| 631 | type ServerTransport interface { |
| 632 | // HandleStreams receives incoming streams using the given handler. |
| 633 | HandleStreams(func(*Stream), func(context.Context, string) context.Context) |
| 634 | |
| 635 | // WriteHeader sends the header metadata for the given stream. |
| 636 | // WriteHeader may not be called on all streams. |
| 637 | WriteHeader(s *Stream, md metadata.MD) error |
| 638 | |
| 639 | // Write sends the data for the given stream. |
| 640 | // Write may not be called on all streams. |
| 641 | Write(s *Stream, hdr []byte, data []byte, opts *Options) error |
| 642 | |
| 643 | // WriteStatus sends the status of a stream to the client. WriteStatus is |
| 644 | // the final call made on a stream and always occurs. |
| 645 | WriteStatus(s *Stream, st *status.Status) error |
| 646 | |
| 647 | // Close tears down the transport. Once it is called, the transport |
| 648 | // should not be accessed any more. All the pending streams and their |
| 649 | // handlers will be terminated asynchronously. |
| 650 | Close() error |
| 651 | |
| 652 | // RemoteAddr returns the remote network address. |
| 653 | RemoteAddr() net.Addr |
| 654 | |
| 655 | // Drain notifies the client this ServerTransport stops accepting new RPCs. |
| 656 | Drain() |
| 657 | |
| 658 | // IncrMsgSent increments the number of message sent through this transport. |
| 659 | IncrMsgSent() |
| 660 | |
| 661 | // IncrMsgRecv increments the number of message received through this transport. |
| 662 | IncrMsgRecv() |
| 663 | } |
| 664 | |
| 665 | // connectionErrorf creates an ConnectionError with the specified error description. |
| 666 | func connectionErrorf(temp bool, e error, format string, a ...interface{}) ConnectionError { |
| 667 | return ConnectionError{ |
| 668 | Desc: fmt.Sprintf(format, a...), |
| 669 | temp: temp, |
| 670 | err: e, |
| 671 | } |
| 672 | } |
| 673 | |
| 674 | // ConnectionError is an error that results in the termination of the |
| 675 | // entire connection and the retry of all the active streams. |
| 676 | type ConnectionError struct { |
| 677 | Desc string |
| 678 | temp bool |
| 679 | err error |
| 680 | } |
| 681 | |
| 682 | func (e ConnectionError) Error() string { |
| 683 | return fmt.Sprintf("connection error: desc = %q", e.Desc) |
| 684 | } |
| 685 | |
| 686 | // Temporary indicates if this connection error is temporary or fatal. |
| 687 | func (e ConnectionError) Temporary() bool { |
| 688 | return e.temp |
| 689 | } |
| 690 | |
| 691 | // Origin returns the original error of this connection error. |
| 692 | func (e ConnectionError) Origin() error { |
| 693 | // Never return nil error here. |
| 694 | // If the original error is nil, return itself. |
| 695 | if e.err == nil { |
| 696 | return e |
| 697 | } |
| 698 | return e.err |
| 699 | } |
| 700 | |
| 701 | var ( |
| 702 | // ErrConnClosing indicates that the transport is closing. |
| 703 | ErrConnClosing = connectionErrorf(true, nil, "transport is closing") |
| 704 | // errStreamDrain indicates that the stream is rejected because the |
| 705 | // connection is draining. This could be caused by goaway or balancer |
| 706 | // removing the address. |
| 707 | errStreamDrain = status.Error(codes.Unavailable, "the connection is draining") |
| 708 | // errStreamDone is returned from write at the client side to indiacte application |
| 709 | // layer of an error. |
| 710 | errStreamDone = errors.New("the stream is done") |
| 711 | // StatusGoAway indicates that the server sent a GOAWAY that included this |
| 712 | // stream's ID in unprocessed RPCs. |
| 713 | statusGoAway = status.New(codes.Unavailable, "the stream is rejected because server is draining the connection") |
| 714 | ) |
| 715 | |
| 716 | // GoAwayReason contains the reason for the GoAway frame received. |
| 717 | type GoAwayReason uint8 |
| 718 | |
| 719 | const ( |
| 720 | // GoAwayInvalid indicates that no GoAway frame is received. |
| 721 | GoAwayInvalid GoAwayReason = 0 |
| 722 | // GoAwayNoReason is the default value when GoAway frame is received. |
| 723 | GoAwayNoReason GoAwayReason = 1 |
| 724 | // GoAwayTooManyPings indicates that a GoAway frame with |
| 725 | // ErrCodeEnhanceYourCalm was received and that the debug data said |
| 726 | // "too_many_pings". |
| 727 | GoAwayTooManyPings GoAwayReason = 2 |
| 728 | ) |
| 729 | |
| 730 | // channelzData is used to store channelz related data for http2Client and http2Server. |
| 731 | // These fields cannot be embedded in the original structs (e.g. http2Client), since to do atomic |
| 732 | // operation on int64 variable on 32-bit machine, user is responsible to enforce memory alignment. |
| 733 | // Here, by grouping those int64 fields inside a struct, we are enforcing the alignment. |
| 734 | type channelzData struct { |
| 735 | kpCount int64 |
| 736 | // The number of streams that have started, including already finished ones. |
| 737 | streamsStarted int64 |
| 738 | // Client side: The number of streams that have ended successfully by receiving |
| 739 | // EoS bit set frame from server. |
| 740 | // Server side: The number of streams that have ended successfully by sending |
| 741 | // frame with EoS bit set. |
| 742 | streamsSucceeded int64 |
| 743 | streamsFailed int64 |
| 744 | // lastStreamCreatedTime stores the timestamp that the last stream gets created. It is of int64 type |
| 745 | // instead of time.Time since it's more costly to atomically update time.Time variable than int64 |
| 746 | // variable. The same goes for lastMsgSentTime and lastMsgRecvTime. |
| 747 | lastStreamCreatedTime int64 |
| 748 | msgSent int64 |
| 749 | msgRecv int64 |
| 750 | lastMsgSentTime int64 |
| 751 | lastMsgRecvTime int64 |
| 752 | } |
| 753 | |
| 754 | // ContextErr converts the error from context package into a status error. |
| 755 | func ContextErr(err error) error { |
| 756 | switch err { |
| 757 | case context.DeadlineExceeded: |
| 758 | return status.Error(codes.DeadlineExceeded, err.Error()) |
| 759 | case context.Canceled: |
| 760 | return status.Error(codes.Canceled, err.Error()) |
| 761 | } |
| 762 | return status.Errorf(codes.Internal, "Unexpected error from context packet: %v", err) |
| 763 | } |