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Published: Jul 31, 2018 License: Apache-2.0 Imports: 33 Imported by: 0



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.



This section is empty.


View Source
var (
	// ErrIllegalHeaderWrite indicates that setting header is illegal because of
	// the stream's state.
	ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHeader was already called")
	// ErrHeaderListSizeLimitViolation indicates that the header list size is larger
	// than the limit set by peer.
	ErrHeaderListSizeLimitViolation = errors.New("transport: trying to send header list size larger than the limit set by peer")
View Source
var (
	// ErrConnClosing indicates that the transport is closing.
	ErrConnClosing = connectionErrorf(true, nil, "transport is closing")


func ContextErr

func ContextErr(err error) error

ContextErr converts the error from context package into a status error.


type CallHdr

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
	// for more details.
	ContentSubtype string

	PreviousAttempts int // value of grpc-previous-rpc-attempts header to set

CallHdr carries the information of a particular RPC.

type ClientTransport

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.

	// IncrMsgRecv increments the number of message received through this transport.

ClientTransport is the common interface for all gRPC client-side transport implementations.

func NewClientTransport

func NewClientTransport(connectCtx, ctx context.Context, target TargetInfo, opts ConnectOptions, onSuccess func()) (ClientTransport, error)

NewClientTransport establishes the transport with the required ConnectOptions and returns it to the caller.

type ConnectOptions

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

ConnectOptions covers all relevant options for communicating with the server.

type ConnectionError

type ConnectionError struct {
	Desc string
	// contains filtered or unexported fields

ConnectionError is an error that results in the termination of the entire connection and the retry of all the active streams.

func (ConnectionError) Error

func (e ConnectionError) Error() string

func (ConnectionError) Origin

func (e ConnectionError) Origin() error

Origin returns the original error of this connection error.

func (ConnectionError) Temporary

func (e ConnectionError) Temporary() bool

Temporary indicates if this connection error is temporary or fatal.

type GoAwayReason

type GoAwayReason uint8

GoAwayReason contains the reason for the GoAway frame received.

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

type Options

type Options struct {
	// Last indicates whether this write is the last piece for
	// this stream.
	Last bool

Options provides additional hints and information for message transmission.

type ServerConfig

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

ServerConfig consists of all the configurations to establish a server transport.

type ServerTransport

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.

	// IncrMsgSent increments the number of message sent through this transport.

	// IncrMsgRecv increments the number of message received through this transport.

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.

func NewServerHandlerTransport

func NewServerHandlerTransport(w http.ResponseWriter, r *http.Request, stats stats.Handler) (ServerTransport, error)

NewServerHandlerTransport returns a ServerTransport handling gRPC from inside an http.Handler. It requires that the http Server supports HTTP/2.

func NewServerTransport

func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error)

NewServerTransport creates a ServerTransport with conn or non-nil error if it fails.

type Stream

type Stream struct {
	// contains filtered or unexported fields

Stream represents an RPC in the transport layer.

func (*Stream) BytesReceived

func (s *Stream) BytesReceived() bool

BytesReceived indicates whether any bytes have been received on this stream.

func (*Stream) ContentSubtype

func (s *Stream) ContentSubtype() string

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 for more details.

func (*Stream) Context

func (s *Stream) Context() context.Context

Context returns the context of the stream.

func (*Stream) Done

func (s *Stream) Done() <-chan struct{}

Done returns a channel which is closed when it receives the final status from the server.

func (*Stream) GoString

func (s *Stream) GoString() string

GoString is implemented by Stream so context.String() won't race when printing %#v.

func (*Stream) Header

func (s *Stream) Header() (metadata.MD, error)

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 (*Stream) Method

func (s *Stream) Method() string

Method returns the method for the stream.

func (*Stream) Read

func (s *Stream) Read(p []byte) (n int, err error)

Read reads all p bytes from the wire for this stream.

func (*Stream) RecvCompress

func (s *Stream) RecvCompress() string

RecvCompress returns the compression algorithm applied to the inbound message. It is empty string if there is no compression applied.

func (*Stream) SendHeader

func (s *Stream) SendHeader(md metadata.MD) error

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 (*Stream) SetHeader

func (s *Stream) SetHeader(md metadata.MD) error

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 (*Stream) SetSendCompress

func (s *Stream) SetSendCompress(str string)

SetSendCompress sets the compression algorithm to the stream.

func (*Stream) SetTrailer

func (s *Stream) SetTrailer(md metadata.MD) error

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 (*Stream) Status

func (s *Stream) Status() *status.Status

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 (*Stream) Trailer

func (s *Stream) Trailer() metadata.MD

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 (*Stream) TrailersOnly

func (s *Stream) TrailersOnly() (bool, error)

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 (*Stream) Unprocessed

func (s *Stream) Unprocessed() bool

Unprocessed indicates whether the server did not process this stream -- i.e. it sent a refused stream or GOAWAY including this stream ID.

type TargetInfo

type TargetInfo struct {
	Addr      string
	Metadata  interface{}
	Authority string

TargetInfo contains the information of the target such as network address and metadata.

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