add support for redis cluster

fix https://github.com/chrislusf/seaweedfs/issues/705

weed/filer2/redis/redis_cluster_store.go

@@ -0,0 +1,31 @@
+package redis
+
+import (
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/go-redis/redis"
+)
+
+func init() {
+	filer2.Stores = append(filer2.Stores, &RedisClusterStore{})
+}
+
+type RedisClusterStore struct {
+	UniversalRedisStore
+}
+
+func (store *RedisClusterStore) GetName() string {
+	return "redis_cluster"
+}
+
+func (store *RedisClusterStore) Initialize(configuration filer2.Configuration) (err error) {
+	return store.initialize(
+		configuration.GetStringSlice("addresses"),
+	)
+}
+
+func (store *RedisClusterStore) initialize(addresses []string) (err error) {
+	store.Client = redis.NewClusterClient(&redis.ClusterOptions{
+		Addrs: addresses,
+	})
+	return
+}