support redis sentinel mode

https://codeflex.co/configuring-redis-cluster-on-linux/

api.json

@@ -93,7 +93,14 @@
 		"endpoint": "127.0.0.1:6379",
 		"poolSize": 10,
 		"database": 0,
-		"password": ""
+		"password": "",
+        "sentinelEnabled": false,
+        "masterName": "mymaster",
+        "sentinelAddrs": [
+            "127.0.0.1:26379",
+            "127.0.0.1:26389",
+            "127.0.0.1:26399"
+        ]
 	},
   
 	"exchange": {

proxy/proxy.go

@@ -169,6 +169,12 @@ func (s *ProxyServer) rpc() *rpc.RPCClient {
 }
 
 func (s *ProxyServer) checkUpstreams() {
+	idx := atomic.LoadInt32(&s.upstream)
+	current := s.upstreams[idx]
+	if current.Check() {
+		return
+	}
+
 	candidate := int32(0)
 	backup := false
 

storage/redis.go

@@ -16,10 +16,13 @@ import (
 )
 
 type Config struct {
-	Endpoint string `json:"endpoint"`
-	Password string `json:"password"`
-	Database int64  `json:"database"`
-	PoolSize int    `json:"poolSize"`
+	SentinelEnabled bool     `json:"sentinelEnabled"`
+	Endpoint        string   `json:"endpoint"`
+	Password        string   `json:"password"`
+	Database        int64    `json:"database"`
+	PoolSize        int      `json:"poolSize"`
+	MasterName      string   `json:"masterName"`
+	SentinelAddrs   []string `json:"sentinelAddrs"`
 }
 
 type RedisClient struct {
@@ -156,16 +159,25 @@ type Worker struct {
 }
 
 func NewRedisClient(cfg *Config, prefix string, pplns int64, CoinName string) *RedisClient {
-	options := redis.Options{
-		Addr:     cfg.Endpoint,
-		Password: cfg.Password,
-		DB:       cfg.Database,
-		PoolSize: cfg.PoolSize,
-	}
-	if cfg.Endpoint[0:1] == "/" {
-		options.Network = "unix"
+	var client *redis.Client
+	if cfg.SentinelEnabled && len(cfg.MasterName) != 0 && len(cfg.SentinelAddrs) != 0 {
+		// sentinel mode
+		client = redis.NewFailoverClient(&redis.FailoverOptions{
+			MasterName:    cfg.MasterName,
+			SentinelAddrs: cfg.SentinelAddrs,
+			Password:      cfg.Password,
+			DB:            cfg.Database,
+			PoolSize:      cfg.PoolSize,
+		})
+	} else {
+		// single instance
+		client = redis.NewClient(&redis.Options{
+			Addr:     cfg.Endpoint,
+			Password: cfg.Password,
+			DB:       cfg.Database,
+			PoolSize: cfg.PoolSize,
+		})
 	}
-	client := redis.NewClient(&options)
 	return &RedisClient{client: client, prefix: prefix, pplns: pplns, CoinName: CoinName}
 }