initial import

core/rpc/rrclient.go

@@ -0,0 +1,40 @@
+package rpc
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+
+	"google.golang.org/grpc"
+)
+
+type RRClient struct {
+	conns []*grpc.ClientConn
+	index int
+	lock  sync.Mutex
+}
+
+func NewRRClient(endpoints []string) (*RRClient, error) {
+	var conns []*grpc.ClientConn
+	for _, endpoint := range endpoints {
+		conn, err := dial(endpoint)
+		if err != nil {
+			return nil, err
+		}
+
+		conns = append(conns, conn)
+	}
+
+	rand.Seed(time.Now().UnixNano())
+	return &RRClient{
+		conns: conns,
+		index: rand.Intn(len(conns)),
+	}, nil
+}
+
+func (c *RRClient) Next() *grpc.ClientConn {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.index = (c.index + 1) % len(c.conns)
+	return c.conns[c.index]
+}