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Diffstat (limited to 'vendor/google.golang.org/grpc/internal/transport/transport.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/internal/transport/transport.go | 709 |
1 files changed, 709 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/internal/transport/transport.go b/vendor/google.golang.org/grpc/internal/transport/transport.go new file mode 100644 index 0000000..644cf11 --- /dev/null +++ b/vendor/google.golang.org/grpc/internal/transport/transport.go @@ -0,0 +1,709 @@ +/* + * + * 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 transport defines and implements message oriented communication +// channel to complete various transactions (e.g., an RPC). It is meant for +// grpc-internal usage and is not intended to be imported directly by users. +package transport + +import ( + "errors" + "fmt" + "io" + "net" + "sync" + "sync/atomic" + + "golang.org/x/net/context" + "google.golang.org/grpc/codes" + "google.golang.org/grpc/credentials" + "google.golang.org/grpc/keepalive" + "google.golang.org/grpc/metadata" + "google.golang.org/grpc/stats" + "google.golang.org/grpc/status" + "google.golang.org/grpc/tap" +) + +// recvMsg represents the received msg from the transport. All transport +// protocol specific info has been removed. +type recvMsg struct { + data []byte + // nil: received some data + // io.EOF: stream is completed. data is nil. + // other non-nil error: transport failure. data is nil. + err error +} + +// recvBuffer is an unbounded channel of recvMsg structs. +// Note recvBuffer differs from controlBuffer only in that recvBuffer +// holds a channel of only recvMsg structs instead of objects implementing "item" interface. +// recvBuffer is written to much more often than +// controlBuffer and using strict recvMsg structs helps avoid allocation in "recvBuffer.put" +type recvBuffer struct { + c chan recvMsg + mu sync.Mutex + backlog []recvMsg + err error +} + +func newRecvBuffer() *recvBuffer { + b := &recvBuffer{ + c: make(chan recvMsg, 1), + } + return b +} + +func (b *recvBuffer) put(r recvMsg) { + b.mu.Lock() + if b.err != nil { + b.mu.Unlock() + // An error had occurred earlier, don't accept more + // data or errors. + return + } + b.err = r.err + if len(b.backlog) == 0 { + select { + case b.c <- r: + b.mu.Unlock() + return + default: + } + } + b.backlog = append(b.backlog, r) + b.mu.Unlock() +} + +func (b *recvBuffer) load() { + b.mu.Lock() + if len(b.backlog) > 0 { + select { + case b.c <- b.backlog[0]: + b.backlog[0] = recvMsg{} + b.backlog = b.backlog[1:] + default: + } + } + b.mu.Unlock() +} + +// get returns the channel that receives a recvMsg in the buffer. +// +// Upon receipt of a recvMsg, the caller should call load to send another +// recvMsg onto the channel if there is any. +func (b *recvBuffer) get() <-chan recvMsg { + return b.c +} + +// +// recvBufferReader implements io.Reader interface to read the data from +// recvBuffer. +type recvBufferReader struct { + ctx context.Context + ctxDone <-chan struct{} // cache of ctx.Done() (for performance). + recv *recvBuffer + last []byte // Stores the remaining data in the previous calls. + err error +} + +// Read reads the next len(p) bytes from last. If last is drained, it tries to +// read additional data from recv. It blocks if there no additional data available +// in recv. If Read returns any non-nil error, it will continue to return that error. +func (r *recvBufferReader) Read(p []byte) (n int, err error) { + if r.err != nil { + return 0, r.err + } + n, r.err = r.read(p) + return n, r.err +} + +func (r *recvBufferReader) read(p []byte) (n int, err error) { + if r.last != nil && len(r.last) > 0 { + // Read remaining data left in last call. + copied := copy(p, r.last) + r.last = r.last[copied:] + return copied, nil + } + select { + case <-r.ctxDone: + return 0, ContextErr(r.ctx.Err()) + case m := <-r.recv.get(): + r.recv.load() + if m.err != nil { + return 0, m.err + } + copied := copy(p, m.data) + r.last = m.data[copied:] + return copied, nil + } +} + +type streamState uint32 + +const ( + streamActive streamState = iota + streamWriteDone // EndStream sent + streamReadDone // EndStream received + streamDone // the entire stream is finished. +) + +// Stream represents an RPC in the transport layer. +type Stream struct { + id uint32 + st ServerTransport // nil for client side Stream + ctx context.Context // the associated context of the stream + cancel context.CancelFunc // always nil for client side Stream + done chan struct{} // closed at the end of stream to unblock writers. On the client side. + ctxDone <-chan struct{} // same as done chan but for server side. Cache of ctx.Done() (for performance) + method string // the associated RPC method of the stream + recvCompress string + sendCompress string + buf *recvBuffer + trReader io.Reader + fc *inFlow + recvQuota uint32 + wq *writeQuota + + // Callback to state application's intentions to read data. This + // is used to adjust flow control, if needed. + requestRead func(int) + + headerChan chan struct{} // closed to indicate the end of header metadata. + headerDone uint32 // set when headerChan is closed. Used to avoid closing headerChan multiple times. + + // hdrMu protects header and trailer metadata on the server-side. + hdrMu sync.Mutex + header metadata.MD // the received header metadata. + trailer metadata.MD // the key-value map of trailer metadata. + + noHeaders bool // set if the client never received headers (set only after the stream is done). + + // On the server-side, headerSent is atomically set to 1 when the headers are sent out. + headerSent uint32 + + state streamState + + // On client-side it is the status error received from the server. + // On server-side it is unused. + status *status.Status + + bytesReceived uint32 // indicates whether any bytes have been received on this stream + unprocessed uint32 // set if the server sends a refused stream or GOAWAY including this stream + + // contentSubtype is the content-subtype for requests. + // this must be lowercase or the behavior is undefined. + contentSubtype string +} + +// isHeaderSent is only valid on the server-side. +func (s *Stream) isHeaderSent() bool { + return atomic.LoadUint32(&s.headerSent) == 1 +} + +// updateHeaderSent updates headerSent and returns true +// if it was alreay set. It is valid only on server-side. +func (s *Stream) updateHeaderSent() bool { + return atomic.SwapUint32(&s.headerSent, 1) == 1 +} + +func (s *Stream) swapState(st streamState) streamState { + return streamState(atomic.SwapUint32((*uint32)(&s.state), uint32(st))) +} + +func (s *Stream) compareAndSwapState(oldState, newState streamState) bool { + return atomic.CompareAndSwapUint32((*uint32)(&s.state), uint32(oldState), uint32(newState)) +} + +func (s *Stream) getState() streamState { + return streamState(atomic.LoadUint32((*uint32)(&s.state))) +} + +func (s *Stream) waitOnHeader() error { + if s.headerChan == nil { + // On the server headerChan is always nil since a stream originates + // only after having received headers. + return nil + } + select { + case <-s.ctx.Done(): + return ContextErr(s.ctx.Err()) + case <-s.headerChan: + return nil + } +} + +// RecvCompress returns the compression algorithm applied to the inbound +// message. It is empty string if there is no compression applied. +func (s *Stream) RecvCompress() string { + if err := s.waitOnHeader(); err != nil { + return "" + } + return s.recvCompress +} + +// SetSendCompress sets the compression algorithm to the stream. +func (s *Stream) SetSendCompress(str string) { + s.sendCompress = str +} + +// Done returns a channel which is closed when it receives the final status +// from the server. +func (s *Stream) Done() <-chan struct{} { + return s.done +} + +// Header acquires the key-value pairs of header metadata once it +// is available. It blocks until i) the metadata is ready or ii) there is no +// header metadata or iii) the stream is canceled/expired. +func (s *Stream) Header() (metadata.MD, error) { + err := s.waitOnHeader() + // Even if the stream is closed, header is returned if available. + select { + case <-s.headerChan: + if s.header == nil { + return nil, nil + } + return s.header.Copy(), nil + default: + } + return nil, err +} + +// TrailersOnly blocks until a header or trailers-only frame is received and +// then returns true if the stream was trailers-only. If the stream ends +// before headers are received, returns true, nil. If a context error happens +// first, returns it as a status error. Client-side only. +func (s *Stream) TrailersOnly() (bool, error) { + err := s.waitOnHeader() + if err != nil { + return false, err + } + // if !headerDone, some other connection error occurred. + return s.noHeaders && atomic.LoadUint32(&s.headerDone) == 1, nil +} + +// Trailer returns the cached trailer metedata. Note that if it is not called +// after the entire stream is done, it could return an empty MD. Client +// side only. +// It can be safely read only after stream has ended that is either read +// or write have returned io.EOF. +func (s *Stream) Trailer() metadata.MD { + c := s.trailer.Copy() + return c +} + +// ContentSubtype returns the content-subtype for a request. For example, a +// content-subtype of "proto" will result in a content-type of +// "application/grpc+proto". This will always be lowercase. See +// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests for +// more details. +func (s *Stream) ContentSubtype() string { + return s.contentSubtype +} + +// Context returns the context of the stream. +func (s *Stream) Context() context.Context { + return s.ctx +} + +// Method returns the method for the stream. +func (s *Stream) Method() string { + return s.method +} + +// Status returns the status received from the server. +// Status can be read safely only after the stream has ended, +// that is, after Done() is closed. +func (s *Stream) Status() *status.Status { + return s.status +} + +// SetHeader sets the header metadata. This can be called multiple times. +// Server side only. +// This should not be called in parallel to other data writes. +func (s *Stream) SetHeader(md metadata.MD) error { + if md.Len() == 0 { + return nil + } + if s.isHeaderSent() || s.getState() == streamDone { + return ErrIllegalHeaderWrite + } + s.hdrMu.Lock() + s.header = metadata.Join(s.header, md) + s.hdrMu.Unlock() + return nil +} + +// SendHeader sends the given header metadata. The given metadata is +// combined with any metadata set by previous calls to SetHeader and +// then written to the transport stream. +func (s *Stream) SendHeader(md metadata.MD) error { + return s.st.WriteHeader(s, md) +} + +// SetTrailer sets the trailer metadata which will be sent with the RPC status +// by the server. This can be called multiple times. Server side only. +// This should not be called parallel to other data writes. +func (s *Stream) SetTrailer(md metadata.MD) error { + if md.Len() == 0 { + return nil + } + if s.getState() == streamDone { + return ErrIllegalHeaderWrite + } + s.hdrMu.Lock() + s.trailer = metadata.Join(s.trailer, md) + s.hdrMu.Unlock() + return nil +} + +func (s *Stream) write(m recvMsg) { + s.buf.put(m) +} + +// Read reads all p bytes from the wire for this stream. +func (s *Stream) Read(p []byte) (n int, err error) { + // Don't request a read if there was an error earlier + if er := s.trReader.(*transportReader).er; er != nil { + return 0, er + } + s.requestRead(len(p)) + return io.ReadFull(s.trReader, p) +} + +// tranportReader reads all the data available for this Stream from the transport and +// passes them into the decoder, which converts them into a gRPC message stream. +// The error is io.EOF when the stream is done or another non-nil error if +// the stream broke. +type transportReader struct { + reader io.Reader + // The handler to control the window update procedure for both this + // particular stream and the associated transport. + windowHandler func(int) + er error +} + +func (t *transportReader) Read(p []byte) (n int, err error) { + n, err = t.reader.Read(p) + if err != nil { + t.er = err + return + } + t.windowHandler(n) + return +} + +// BytesReceived indicates whether any bytes have been received on this stream. +func (s *Stream) BytesReceived() bool { + return atomic.LoadUint32(&s.bytesReceived) == 1 +} + +// Unprocessed indicates whether the server did not process this stream -- +// i.e. it sent a refused stream or GOAWAY including this stream ID. +func (s *Stream) Unprocessed() bool { + return atomic.LoadUint32(&s.unprocessed) == 1 +} + +// GoString is implemented by Stream so context.String() won't +// race when printing %#v. +func (s *Stream) GoString() string { + return fmt.Sprintf("<stream: %p, %v>", s, s.method) +} + +// state of transport +type transportState int + +const ( + reachable transportState = iota + closing + draining +) + +// ServerConfig consists of all the configurations to establish a server transport. +type ServerConfig struct { + MaxStreams uint32 + AuthInfo credentials.AuthInfo + InTapHandle tap.ServerInHandle + StatsHandler stats.Handler + KeepaliveParams keepalive.ServerParameters + KeepalivePolicy keepalive.EnforcementPolicy + InitialWindowSize int32 + InitialConnWindowSize int32 + WriteBufferSize int + ReadBufferSize int + ChannelzParentID int64 + MaxHeaderListSize *uint32 +} + +// NewServerTransport creates a ServerTransport with conn or non-nil error +// if it fails. +func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) { + return newHTTP2Server(conn, config) +} + +// ConnectOptions covers all relevant options for communicating with the server. +type ConnectOptions struct { + // UserAgent is the application user agent. + UserAgent string + // Dialer specifies how to dial a network address. + Dialer func(context.Context, string) (net.Conn, error) + // FailOnNonTempDialError specifies if gRPC fails on non-temporary dial errors. + FailOnNonTempDialError bool + // PerRPCCredentials stores the PerRPCCredentials required to issue RPCs. + PerRPCCredentials []credentials.PerRPCCredentials + // TransportCredentials stores the Authenticator required to setup a client connection. + TransportCredentials credentials.TransportCredentials + // KeepaliveParams stores the keepalive parameters. + KeepaliveParams keepalive.ClientParameters + // StatsHandler stores the handler for stats. + StatsHandler stats.Handler + // InitialWindowSize sets the initial window size for a stream. + InitialWindowSize int32 + // InitialConnWindowSize sets the initial window size for a connection. + InitialConnWindowSize int32 + // WriteBufferSize sets the size of write buffer which in turn determines how much data can be batched before it's written on the wire. + WriteBufferSize int + // ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall. + ReadBufferSize int + // ChannelzParentID sets the addrConn id which initiate the creation of this client transport. + ChannelzParentID int64 + // MaxHeaderListSize sets the max (uncompressed) size of header list that is prepared to be received. + MaxHeaderListSize *uint32 +} + +// TargetInfo contains the information of the target such as network address and metadata. +type TargetInfo struct { + Addr string + Metadata interface{} + Authority string +} + +// NewClientTransport establishes the transport with the required ConnectOptions +// and returns it to the caller. +func NewClientTransport(connectCtx, ctx context.Context, target TargetInfo, opts ConnectOptions, onSuccess func()) (ClientTransport, error) { + return newHTTP2Client(connectCtx, ctx, target, opts, onSuccess) +} + +// Options provides additional hints and information for message +// transmission. +type Options struct { + // Last indicates whether this write is the last piece for + // this stream. + Last bool +} + +// CallHdr carries the information of a particular RPC. +type CallHdr struct { + // Host specifies the peer's host. + Host string + + // Method specifies the operation to perform. + Method string + + // SendCompress specifies the compression algorithm applied on + // outbound message. + SendCompress string + + // Creds specifies credentials.PerRPCCredentials for a call. + Creds credentials.PerRPCCredentials + + // ContentSubtype specifies the content-subtype for a request. For example, a + // content-subtype of "proto" will result in a content-type of + // "application/grpc+proto". The value of ContentSubtype must be all + // lowercase, otherwise the behavior is undefined. See + // https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests + // for more details. + ContentSubtype string + + PreviousAttempts int // value of grpc-previous-rpc-attempts header to set +} + +// ClientTransport is the common interface for all gRPC client-side transport +// implementations. +type ClientTransport interface { + // Close tears down this transport. Once it returns, the transport + // should not be accessed any more. The caller must make sure this + // is called only once. + Close() error + + // GracefulClose starts to tear down the transport. It stops accepting + // new RPCs and wait the completion of the pending RPCs. + GracefulClose() error + + // Write sends the data for the given stream. A nil stream indicates + // the write is to be performed on the transport as a whole. + Write(s *Stream, hdr []byte, data []byte, opts *Options) error + + // NewStream creates a Stream for an RPC. + NewStream(ctx context.Context, callHdr *CallHdr) (*Stream, error) + + // CloseStream clears the footprint of a stream when the stream is + // not needed any more. The err indicates the error incurred when + // CloseStream is called. Must be called when a stream is finished + // unless the associated transport is closing. + CloseStream(stream *Stream, err error) + + // Error returns a channel that is closed when some I/O error + // happens. Typically the caller should have a goroutine to monitor + // this in order to take action (e.g., close the current transport + // and create a new one) in error case. It should not return nil + // once the transport is initiated. + Error() <-chan struct{} + + // GoAway returns a channel that is closed when ClientTransport + // receives the draining signal from the server (e.g., GOAWAY frame in + // HTTP/2). + GoAway() <-chan struct{} + + // GetGoAwayReason returns the reason why GoAway frame was received. + GetGoAwayReason() GoAwayReason + + // IncrMsgSent increments the number of message sent through this transport. + IncrMsgSent() + + // IncrMsgRecv increments the number of message received through this transport. + IncrMsgRecv() +} + +// ServerTransport is the common interface for all gRPC server-side transport +// implementations. +// +// Methods may be called concurrently from multiple goroutines, but +// Write methods for a given Stream will be called serially. +type ServerTransport interface { + // HandleStreams receives incoming streams using the given handler. + HandleStreams(func(*Stream), func(context.Context, string) context.Context) + + // WriteHeader sends the header metadata for the given stream. + // WriteHeader may not be called on all streams. + WriteHeader(s *Stream, md metadata.MD) error + + // Write sends the data for the given stream. + // Write may not be called on all streams. + Write(s *Stream, hdr []byte, data []byte, opts *Options) error + + // WriteStatus sends the status of a stream to the client. WriteStatus is + // the final call made on a stream and always occurs. + WriteStatus(s *Stream, st *status.Status) error + + // Close tears down the transport. Once it is called, the transport + // should not be accessed any more. All the pending streams and their + // handlers will be terminated asynchronously. + Close() error + + // RemoteAddr returns the remote network address. + RemoteAddr() net.Addr + + // Drain notifies the client this ServerTransport stops accepting new RPCs. + Drain() + + // IncrMsgSent increments the number of message sent through this transport. + IncrMsgSent() + + // IncrMsgRecv increments the number of message received through this transport. + IncrMsgRecv() +} + +// connectionErrorf creates an ConnectionError with the specified error description. +func connectionErrorf(temp bool, e error, format string, a ...interface{}) ConnectionError { + return ConnectionError{ + Desc: fmt.Sprintf(format, a...), + temp: temp, + err: e, + } +} + +// ConnectionError is an error that results in the termination of the +// entire connection and the retry of all the active streams. +type ConnectionError struct { + Desc string + temp bool + err error +} + +func (e ConnectionError) Error() string { + return fmt.Sprintf("connection error: desc = %q", e.Desc) +} + +// Temporary indicates if this connection error is temporary or fatal. +func (e ConnectionError) Temporary() bool { + return e.temp +} + +// Origin returns the original error of this connection error. +func (e ConnectionError) Origin() error { + // Never return nil error here. + // If the original error is nil, return itself. + if e.err == nil { + return e + } + return e.err +} + +var ( + // ErrConnClosing indicates that the transport is closing. + ErrConnClosing = connectionErrorf(true, nil, "transport is closing") + // errStreamDrain indicates that the stream is rejected because the + // connection is draining. This could be caused by goaway or balancer + // removing the address. + errStreamDrain = status.Error(codes.Unavailable, "the connection is draining") + // errStreamDone is returned from write at the client side to indiacte application + // layer of an error. + errStreamDone = errors.New("the stream is done") + // StatusGoAway indicates that the server sent a GOAWAY that included this + // stream's ID in unprocessed RPCs. + statusGoAway = status.New(codes.Unavailable, "the stream is rejected because server is draining the connection") +) + +// GoAwayReason contains the reason for the GoAway frame received. +type GoAwayReason uint8 + +const ( + // GoAwayInvalid indicates that no GoAway frame is received. + GoAwayInvalid GoAwayReason = 0 + // GoAwayNoReason is the default value when GoAway frame is received. + GoAwayNoReason GoAwayReason = 1 + // GoAwayTooManyPings indicates that a GoAway frame with + // ErrCodeEnhanceYourCalm was received and that the debug data said + // "too_many_pings". + GoAwayTooManyPings GoAwayReason = 2 +) + +// channelzData is used to store channelz related data for http2Client and http2Server. +// These fields cannot be embedded in the original structs (e.g. http2Client), since to do atomic +// operation on int64 variable on 32-bit machine, user is responsible to enforce memory alignment. +// Here, by grouping those int64 fields inside a struct, we are enforcing the alignment. +type channelzData struct { + kpCount int64 + // The number of streams that have started, including already finished ones. + streamsStarted int64 + // Client side: The number of streams that have ended successfully by receiving + // EoS bit set frame from server. + // Server side: The number of streams that have ended successfully by sending + // frame with EoS bit set. + streamsSucceeded int64 + streamsFailed int64 + // lastStreamCreatedTime stores the timestamp that the last stream gets created. It is of int64 type + // instead of time.Time since it's more costly to atomically update time.Time variable than int64 + // variable. The same goes for lastMsgSentTime and lastMsgRecvTime. + lastStreamCreatedTime int64 + msgSent int64 + msgRecv int64 + lastMsgSentTime int64 + lastMsgRecvTime int64 +} |