Documentation
¶
Overview ¶
Package transport defines and implements message oriented communication channel to complete various transactions (e.g., an RPC).
Index ¶
- Variables
- type CallHdr
- type ClientTransport
- type ConnectOptions
- type ConnectionError
- type Options
- type ServerTransport
- type Stream
- func (s *Stream) Context() context.Context
- func (s *Stream) Done() <-chan struct{}
- func (s *Stream) GoAway() <-chan struct{}
- func (s *Stream) Header() (metadata.MD, error)
- func (s *Stream) Method() string
- func (s *Stream) Read(p []byte) (n int, err error)
- func (s *Stream) RecvCompress() string
- func (s *Stream) ServerTransport() ServerTransport
- func (s *Stream) SetSendCompress(str string)
- func (s *Stream) SetTrailer(md metadata.MD) error
- func (s *Stream) StatusCode() codes.Code
- func (s *Stream) StatusDesc() string
- func (s *Stream) TraceContext(tr trace.Trace)
- func (s *Stream) Trailer() metadata.MD
- type StreamError
Constants ¶
This section is empty.
Variables ¶
var ( // ErrConnClosing indicates that the transport is closing. ErrConnClosing = connectionErrorf(true, nil, "transport is closing") // ErrStreamDrain indicates that the stream is rejected by the server because // the server stops accepting new RPCs. ErrStreamDrain = streamErrorf(codes.Unavailable, "the server stops accepting new RPCs") )
var ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHeader was already called")
ErrIllegalHeaderWrite indicates that setting header is illegal because of the stream's state.
Functions ¶
This section is empty.
Types ¶
type CallHdr ¶
type CallHdr struct {
// Host specifies the peer's host.
Host string
// Method specifies the operation to perform.
Method string
// RecvCompress specifies the compression algorithm applied on
// inbound messages.
RecvCompress string
// SendCompress specifies the compression algorithm applied on
// outbound message.
SendCompress string
// Flush indicates whether a new stream command should be sent
// to the peer without waiting for the first data. This is
// only a hint. The transport may modify the flush decision
// for performance purposes.
Flush bool
}
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, 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 ClientTranspor
// receives the draining signal from the server (e.g., GOAWAY frame in
// HTTP/2).
GoAway() <-chan struct{}
}
ClientTransport is the common interface for all gRPC client-side transport implementations.
func NewClientTransport ¶
func NewClientTransport(ctx context.Context, target string, opts ConnectOptions) (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)
// PerRPCCredentials stores the PerRPCCredentials required to issue RPCs.
PerRPCCredentials []credentials.PerRPCCredentials
// TransportCredentials stores the Authenticator required to setup a client connection.
TransportCredentials credentials.TransportCredentials
}
ConnectOptions covers all relevant options for dialing a 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 ¶ added in v1.0.2
func (e ConnectionError) Origin() error
Origin returns the original error of this connection error.
func (ConnectionError) Temporary ¶ added in v1.0.2
func (e ConnectionError) Temporary() bool
Temporary indicates if this connection error is temporary or fatal.
type Options ¶
type Options struct {
// Last indicates whether this write is the last piece for
// this stream.
Last bool
// Delay is a hint to the transport implementation for whether
// the data could be buffered for a batching write. The
// Transport implementation may ignore the hint.
Delay bool
}
Options provides additional hints and information for message transmission.
type ServerTransport ¶
type ServerTransport interface {
// HandleStreams receives incoming streams using the given handler.
HandleStreams(func(*Stream))
// 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, 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, statusCode codes.Code, statusDesc string) 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()
}
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) (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, maxStreams uint32, authInfo credentials.AuthInfo) (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 StreamFromContext ¶
StreamFromContext returns the stream saved in ctx.
func (*Stream) Done ¶ added in v1.0.2
func (s *Stream) Done() <-chan struct{}
Done returns a chanel which is closed when it receives the final status from the server.
func (*Stream) GoAway ¶ added in v1.0.2
func (s *Stream) GoAway() <-chan struct{}
GoAway returns a channel which is closed when the server sent GoAways signal before this stream was initiated.
func (*Stream) Header ¶
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 cancelled/expired.
func (*Stream) Read ¶
Read 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.
func (*Stream) RecvCompress ¶
RecvCompress returns the compression algorithm applied to the inbound message. It is empty string if there is no compression applied.
func (*Stream) ServerTransport ¶
func (s *Stream) ServerTransport() ServerTransport
ServerTransport returns the underlying ServerTransport for the stream. The client side stream always returns nil.
func (*Stream) SetSendCompress ¶
SetSendCompress sets the compression algorithm to the stream.
func (*Stream) SetTrailer ¶
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.
func (*Stream) StatusCode ¶
StatusCode returns statusCode received from the server.
func (*Stream) StatusDesc ¶
StatusDesc returns statusDesc received from the server.
func (*Stream) TraceContext ¶
TraceContext recreates the context of s with a trace.Trace.
type StreamError ¶
StreamError is an error that only affects one stream within a connection.
func ContextErr ¶
func ContextErr(err error) StreamError
ContextErr converts the error from context package into a StreamError.
func (StreamError) Error ¶
func (e StreamError) Error() string
Source Files