Pool first attempt

client/rpc_client.go

@@ -19,16 +19,16 @@ import (
 type rpcClient struct {
 	once sync.Once
 	opts Options
+	pool *pool
 }
 
 func newRpcClient(opt ...Option) Client {
-	var once sync.Once
-
 	opts := newOptions(opt...)
 
 	rc := &rpcClient{
-		once: once,
+		once: sync.Once{},
 		opts: opts,
+		pool: newPool(),
 	}
 
 	c := Client(rc)
@@ -73,10 +73,15 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 		return errors.InternalServerError("go.micro.client", err.Error())
 	}
 
-	c, err := r.opts.Transport.Dial(address, transport.WithTimeout(opts.DialTimeout))
+	var grr error
+	c, err := r.pool.getConn(address, r.opts.Transport, transport.WithTimeout(opts.DialTimeout))
 	if err != nil {
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
+	defer func() {
+		// defer execution of release
+		r.pool.release(address, c, grr)
+	}()
 
 	stream := &rpcStream{
 		context: ctx,
@@ -107,8 +112,10 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 
 	select {
 	case err := <-ch:
+		grr = err
 		return err
 	case <-ctx.Done():
+		grr = ctx.Err()
 		return errors.New("go.micro.client", fmt.Sprintf("%v", ctx.Err()), 408)
 	}
 }

client/rpc_pool.go

@@ -0,0 +1,71 @@
+package client
+
+import (
+	"sync"
+
+	"github.com/micro/go-micro/transport"
+)
+
+type pool struct {
+	tr transport.Transport
+
+	sync.Mutex
+	conns map[string][]*poolConn
+}
+
+type poolConn struct {
+	transport.Client
+}
+
+var (
+	maxIdleConn = 2
+)
+
+func newPool() *pool {
+	return &pool{
+		conns: make(map[string][]*poolConn),
+	}
+}
+
+// NoOp the Close since we manage it
+func (p *poolConn) Close() error {
+	return nil
+}
+
+func (p *pool) getConn(addr string, tr transport.Transport, opts ...transport.DialOption) (*poolConn, error) {
+	p.Lock()
+	conns, ok := p.conns[addr]
+	// no free conn
+	if !ok || len(conns) == 0 {
+		p.Unlock()
+		// create new conn
+		c, err := tr.Dial(addr, opts...)
+		if err != nil {
+			return nil, err
+		}
+		return &poolConn{c}, nil
+	}
+
+	conn := conns[len(conns)-1]
+	p.conns[addr] = conns[:len(conns)-1]
+	p.Unlock()
+	return conn, nil
+}
+
+func (p *pool) release(addr string, conn *poolConn, err error) {
+	// don't store the conn
+	if err != nil {
+		conn.Client.Close()
+		return
+	}
+
+	// otherwise put it back
+	p.Lock()
+	conns := p.conns[addr]
+	if len(conns) >= maxIdleConn {
+		conn.Client.Close()
+		return
+	}
+	p.conns[addr] = append(conns, conn)
+	p.Unlock()
+}

server/rpc_server.go

@@ -55,50 +55,53 @@ func (s *rpcServer) accept(sock transport.Socket) {
 		}
 	}()
 
-	var msg transport.Message
-	if err := sock.Recv(&msg); err != nil {
-		return
-	}
-
-	// we use this Timeout header to set a server deadline
-	to := msg.Header["Timeout"]
-	// we use this Content-Type header to identify the codec needed
-	ct := msg.Header["Content-Type"]
-
-	cf, err := s.newCodec(ct)
-	// TODO: needs better error handling
-	if err != nil {
-		sock.Send(&transport.Message{
-			Header: map[string]string{
-				"Content-Type": "text/plain",
-			},
-			Body: []byte(err.Error()),
-		})
-		return
-	}
-
-	codec := newRpcPlusCodec(&msg, sock, cf)
-
-	// strip our headers
-	hdr := make(map[string]string)
-	for k, v := range msg.Header {
-		hdr[k] = v
-	}
-	delete(hdr, "Content-Type")
-	delete(hdr, "Timeout")
-
-	ctx := metadata.NewContext(context.Background(), hdr)
-
-	// set the timeout if we have it
-	if len(to) > 0 {
-		if n, err := strconv.ParseUint(to, 10, 64); err == nil {
-			ctx, _ = context.WithTimeout(ctx, time.Duration(n))
+	for {
+		var msg transport.Message
+		if err := sock.Recv(&msg); err != nil {
+			return
 		}
-	}
 
-	// TODO: needs better error handling
-	if err := s.rpc.serveRequest(ctx, codec, ct); err != nil {
-		log.Printf("Unexpected error serving request, closing socket: %v", err)
+		// we use this Timeout header to set a server deadline
+		to := msg.Header["Timeout"]
+		// we use this Content-Type header to identify the codec needed
+		ct := msg.Header["Content-Type"]
+
+		cf, err := s.newCodec(ct)
+		// TODO: needs better error handling
+		if err != nil {
+			sock.Send(&transport.Message{
+				Header: map[string]string{
+					"Content-Type": "text/plain",
+				},
+				Body: []byte(err.Error()),
+			})
+			return
+		}
+
+		codec := newRpcPlusCodec(&msg, sock, cf)
+
+		// strip our headers
+		hdr := make(map[string]string)
+		for k, v := range msg.Header {
+			hdr[k] = v
+		}
+		delete(hdr, "Content-Type")
+		delete(hdr, "Timeout")
+
+		ctx := metadata.NewContext(context.Background(), hdr)
+
+		// set the timeout if we have it
+		if len(to) > 0 {
+			if n, err := strconv.ParseUint(to, 10, 64); err == nil {
+				ctx, _ = context.WithTimeout(ctx, time.Duration(n))
+			}
+		}
+
+		// TODO: needs better error handling
+		if err := s.rpc.serveRequest(ctx, codec, ct); err != nil {
+			log.Printf("Unexpected error serving request, closing socket: %v", err)
+			return
+		}
 	}
 }