transport

package
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 Go to latest Published: Feb 28, 2023 License: Apache-2.0 Imports: 44 Imported by: 0

Documentation

Overview

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.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// ErrIllegalHeaderWrite indicates that setting header is illegal because of
	// the stream's state.
	ErrIllegalHeaderWrite = status.Error(codes.Internal, "transport: SendHeader called multiple times")
	// ErrHeaderListSizeLimitViolation indicates that the header list size is larger
	// than the limit set by peer.
	ErrHeaderListSizeLimitViolation = status.Error(codes.Internal, "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")
)
View Source 
var ErrNoHeaders = errors.New("stream has no headers")

ErrNoHeaders is used as a signal that a trailers only response was received, and is not a real error.

View Source 
var (

	// HTTPStatusConvTab is the HTTP status code to gRPC error code conversion table.
	HTTPStatusConvTab = map[int]codes.Code{

		http.StatusBadRequest: codes.Internal,

		http.StatusUnauthorized: codes.Unauthenticated,

		http.StatusForbidden: codes.PermissionDenied,

		http.StatusNotFound: codes.Unimplemented,

		http.StatusTooManyRequests: codes.Unavailable,

		http.StatusBadGateway: codes.Unavailable,

		http.StatusServiceUnavailable: codes.Unavailable,

		http.StatusGatewayTimeout: codes.Unavailable,
	}
)
View Source 
var MaxStreamID = uint32(math.MaxInt32 * 3 / 4)

MaxStreamID is the upper bound for the stream ID before the current transport gracefully closes and new transport is created for subsequent RPCs. This is set to 75% of 2^31-1. Streams are identified with an unsigned 31-bit integer. It's exported so that tests can override it.

Functions

func ContextErr 

func ContextErr(err error) error

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

func GetConnection 

func GetConnection(ctx context.Context) net.Conn

GetConnection gets the connection from the context.

Types

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
	// 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

	DoneFunc func() // called when the stream is finished
}

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(err error)

	// GracefulClose starts to tear down the transport: the transport will stop
	// accepting new RPCs and NewStream will return error. Once all streams are
	// finished, the transport will close.
	//
	// It does not block.
	GracefulClose()

	// 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, along
	// with a human readable string with debug info.
	GetGoAwayReason() (GoAwayReason, string)

	// RemoteAddr returns the remote network address.
	RemoteAddr() net.Addr

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

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

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

func NewClientTransport 

func NewClientTransport(connectCtx, ctx context.Context, addr resolver.Address, opts ConnectOptions, onClose func(GoAwayReason)) (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. Only one of TransportCredentials and CredsBundle is non-nil.
	TransportCredentials credentials.TransportCredentials
	// CredsBundle is the credentials bundle to be used. Only one of
	// TransportCredentials and CredsBundle is non-nil.
	CredsBundle credentials.Bundle
	// KeepaliveParams stores the keepalive parameters.
	KeepaliveParams keepalive.ClientParameters
	// StatsHandlers stores the handler for stats.
	StatsHandlers []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 *channelz.Identifier
	// MaxHeaderListSize sets the max (uncompressed) size of header list that is prepared to be received.
	MaxHeaderListSize *uint32
	// UseProxy specifies if a proxy should be used.
	UseProxy bool
}

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.

func (ConnectionError) Unwrap 

func (e ConnectionError) Unwrap() error

Unwrap returns the original error of this connection error or nil when the origin is nil.

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 NewStreamError 

type NewStreamError struct {
	Err error

	AllowTransparentRetry bool
}

NewStreamError wraps an error and reports additional information. Typically NewStream errors result in transparent retry, as they mean nothing went onto the wire. However, there are two notable exceptions:

  1. If the stream headers violate the max header list size allowed by the server. It's possible this could succeed on another transport, even if it's unlikely, but do not transparently retry.
  2. If the credentials errored when requesting their headers. In this case, it's possible a retry can fix the problem, but indefinitely transparently retrying is not appropriate as it is likely the credentials, if they can eventually succeed, would need I/O to do so.

func (NewStreamError) Error 

func (e NewStreamError) Error() string

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
	ConnectionTimeout     time.Duration
	Credentials           credentials.TransportCredentials
	InTapHandle           tap.ServerInHandle
	StatsHandlers         []stats.Handler
	KeepaliveParams       keepalive.ServerParameters
	KeepalivePolicy       keepalive.EnforcementPolicy
	InitialWindowSize     int32
	InitialConnWindowSize int32
	WriteBufferSize       int
	ReadBufferSize        int
	ChannelzParentID      *channelz.Identifier
	MaxHeaderListSize     *uint32
	HeaderTableSize       *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(err 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()
}

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, or writes an HTTP error to w and returns an error. It requires that the http Server supports HTTP/2.

func NewServerTransport 

func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error)

NewServerTransport creates a http2 transport with conn and configuration options from config.

It returns a non-nil transport and a nil error on success. On failure, it returns a nil transport and a non-nil error. For a special case where the underlying conn gets closed before the client preface could be read, it returns a nil transport and a nil error.

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) ClientAdvertisedCompressors 

func (s *Stream) ClientAdvertisedCompressors() string

ClientAdvertisedCompressors returns the compressor names advertised by the client via grpc-accept-encoding header.

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 https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#requests 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 returns the header metadata of the stream.

On client side, it 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.

On server side, it returns the out header after t.WriteHeader is called. It does not block and must not be called until after WriteHeader.

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) SendCompress 

func (s *Stream) SendCompress() string

SendCompress returns the send compressor name.

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(name string) error

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

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. 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.

Source Files

View all Source files

Directories

Path Synopsis
Package networktype declares the network type to be used in the default dialer.
 Package networktype declares the network type to be used in the default dialer.

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