v3 refactor (#1868)

* Move to v3

Co-authored-by: Ben Toogood <bentoogood@gmail.com>

server/mucp/rpc_stream.go

@@ -0,0 +1,105 @@
+package mucp
+
+import (
+	"context"
+	"errors"
+	"io"
+	"sync"
+
+	"github.com/micro/go-micro/v3/codec"
+	"github.com/micro/go-micro/v3/server"
+)
+
+// Implements the Streamer interface
+type rpcStream struct {
+	sync.RWMutex
+	id      string
+	closed  bool
+	err     error
+	request server.Request
+	codec   codec.Codec
+	context context.Context
+}
+
+func (r *rpcStream) Context() context.Context {
+	return r.context
+}
+
+func (r *rpcStream) Request() server.Request {
+	return r.request
+}
+
+func (r *rpcStream) Send(msg interface{}) error {
+	r.Lock()
+	defer r.Unlock()
+
+	resp := codec.Message{
+		Target:   r.request.Service(),
+		Method:   r.request.Method(),
+		Endpoint: r.request.Endpoint(),
+		Id:       r.id,
+		Type:     codec.Response,
+	}
+
+	if err := r.codec.Write(&resp, msg); err != nil {
+		r.err = err
+	}
+
+	return nil
+}
+
+func (r *rpcStream) Recv(msg interface{}) error {
+	req := new(codec.Message)
+	req.Type = codec.Request
+
+	err := r.codec.ReadHeader(req, req.Type)
+	r.Lock()
+	defer r.Unlock()
+	if err != nil {
+		// discard body
+		r.codec.ReadBody(nil)
+		r.err = err
+		return err
+	}
+
+	// check the error
+	if len(req.Error) > 0 {
+		// Check the client closed the stream
+		switch req.Error {
+		case lastStreamResponseError.Error():
+			// discard body
+			r.Unlock()
+			r.codec.ReadBody(nil)
+			r.Lock()
+			r.err = io.EOF
+			return io.EOF
+		default:
+			return errors.New(req.Error)
+		}
+	}
+
+	// we need to stay up to date with sequence numbers
+	r.id = req.Id
+	r.Unlock()
+	err = r.codec.ReadBody(msg)
+	r.Lock()
+	if err != nil {
+		r.err = err
+		return err
+	}
+
+	return nil
+}
+
+func (r *rpcStream) Error() error {
+	r.RLock()
+	defer r.RUnlock()
+	return r.err
+}
+
+func (r *rpcStream) Close() error {
+	r.Lock()
+	defer r.Unlock()
+	r.closed = true
+	return r.codec.Close()
+}