diff --git a/stream.go b/stream.go index da478938fc0b..6f71d4d03a38 100644 --- a/stream.go +++ b/stream.go @@ -59,43 +59,20 @@ type StreamDesc struct { // Stream defines the common interface a client or server stream has to satisfy. // -// All errors returned from Stream are compatible with the status package. +// Deprecated: See ClientStream and ServerStream documentation instead. type Stream interface { - // Context returns the context for this stream. If called from the client, - // Should be done after Header or RecvMsg. Otherwise, retries may not be - // possible to perform. + // Deprecated: See ClientStream and ServerStream documentation instead. Context() context.Context - // SendMsg is generally called by generated code. On error, SendMsg aborts - // the stream and returns an RPC status on the client side. On the server - // side, it simply returns the error to the caller. - // - // SendMsg blocks until: - // - It schedules m with the transport, or - // - The stream is done, or - // - The stream breaks. - // - // SendMsg does not wait for an ack. An untimely stream closure - // can result in any buffered messages along the way (including - // those in the client-side buffer that comes with gRPC by default) - // being lost. To ensure delivery, users must call RecvMsg until - // receiving an EOF before closing the stream. - // - // It's safe to have a goroutine calling SendMsg and another - // goroutine calling RecvMsg on the same stream at the same - // time. It is not safe to call SendMsg on the same stream - // in different goroutines. + // Deprecated: See ClientStream and ServerStream documentation instead. SendMsg(m interface{}) error - // RecvMsg blocks until it receives a message or the stream is - // done. On client side, it returns io.EOF when the stream is done. On - // any other error, it aborts the stream and returns an RPC status. On - // server side, it simply returns the error to the caller. - // It's safe to have a goroutine calling SendMsg and another goroutine calling - // recvMsg on the same stream at the same time. - // But it is not safe to call RecvMsg on the same stream in different goroutines. + // Deprecated: See ClientStream and ServerStream documentation instead. RecvMsg(m interface{}) error } -// ClientStream defines the interface a client stream has to satisfy. +// ClientStream defines the client-side behavior of a streaming RPC. +// +// All errors returned from ClientStream methods are compatible with the +// status package. type ClientStream interface { // Header returns the header metadata received from the server if there // is any. It blocks if the metadata is not ready to read. @@ -107,13 +84,38 @@ type ClientStream interface { // CloseSend closes the send direction of the stream. It closes the stream // when non-nil error is met. CloseSend() error - // Stream.SendMsg() may return a non-nil error when something wrong happens sending - // the request. The returned error indicates the status of this sending, not the final - // status of the RPC. + // Context returns the context for this stream. + // + // It should not be called until after Header or RecvMsg has returned. Once + // called, subsequent client-side retries are disabled. + Context() context.Context + // SendMsg is generally called by generated code. On error, SendMsg aborts + // the stream. If the error was generated by the client, the status is + // returned directly; otherwise, io.EOF is returned and the status of + // the stream may be discovered using RecvMsg. + // + // SendMsg blocks until: + // - There is sufficient flow control to schedule m with the transport, or + // - The stream is done, or + // - The stream breaks. + // + // SendMsg does not wait until the message is received by the server. An + // untimely stream closure may result in lost messages. To ensure delivery, + // users should ensure the RPC completed successfully using RecvMsg. // - // Always call Stream.RecvMsg() to drain the stream and get the final - // status, otherwise there could be leaked resources. - Stream + // It is safe to have a goroutine calling SendMsg and another goroutine + // calling RecvMsg on the same stream at the same time, but it is not safe + // to call SendMsg on the same stream in different goroutines. + SendMsg(m interface{}) error + // RecvMsg blocks until it receives a message into m or the stream is + // done. It returns io.EOF when the stream completes successfully. On + // any other error, the stream is aborted and the error contains the RPC + // status. + // + // It is safe to have a goroutine calling SendMsg and another goroutine + // calling RecvMsg on the same stream at the same time, but it is not + // safe to call RecvMsg on the same stream in different goroutines. + RecvMsg(m interface{}) error } // NewStream creates a new Stream for the client side. This is typically @@ -144,8 +146,6 @@ func (cc *ClientConn) NewStream(ctx context.Context, desc *StreamDesc, method st } // NewClientStream is a wrapper for ClientConn.NewStream. -// -// DEPRECATED: Use ClientConn.NewStream instead. func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) { return cc.NewStream(ctx, desc, method, opts...) } @@ -845,7 +845,10 @@ func (a *csAttempt) finish(err error) { a.mu.Unlock() } -// ServerStream defines the interface a server stream has to satisfy. +// ServerStream defines the server-side behavior of a streaming RPC. +// +// All errors returned from ServerStream methods are compatible with the +// status package. type ServerStream interface { // SetHeader sets the header metadata. It may be called multiple times. // When call multiple times, all the provided metadata will be merged. @@ -861,7 +864,32 @@ type ServerStream interface { // SetTrailer sets the trailer metadata which will be sent with the RPC status. // When called more than once, all the provided metadata will be merged. SetTrailer(metadata.MD) - Stream + // Context returns the context for this stream. + Context() context.Context + // SendMsg sends a message. On error, SendMsg aborts the stream and the + // error is returned directly. + // + // SendMsg blocks until: + // - There is sufficient flow control to schedule m with the transport, or + // - The stream is done, or + // - The stream breaks. + // + // SendMsg does not wait until the message is received by the client. An + // untimely stream closure may result in lost messages. + // + // It is safe to have a goroutine calling SendMsg and another goroutine + // calling RecvMsg on the same stream at the same time, but it is not safe + // to call SendMsg on the same stream in different goroutines. + SendMsg(m interface{}) error + // RecvMsg blocks until it receives a message into m or the stream is + // done. It returns io.EOF when the client has performed a CloseSend. On + // any non-EOF error, the stream is aborted and the error contains the + // RPC status. + // + // It is safe to have a goroutine calling SendMsg and another goroutine + // calling RecvMsg on the same stream at the same time, but it is not + // safe to call RecvMsg on the same stream in different goroutines. + RecvMsg(m interface{}) error } // serverStream implements a server side Stream.