Add the Protocol attribute to the Redis configuration (#3109)

contrib/nosql/redis/redis.go

@@ -61,6 +61,7 @@ func New(config *gredis.Config) *Redis {
 		WriteTimeout:    config.WriteTimeout,
 		MasterName:      config.MasterName,
 		TLSConfig:       config.TLSConfig,
+		Protocol:        config.Protocol,
 	}
 
 	var client redis.UniversalClient

database/gredis/gredis_config.go

@@ -40,6 +40,7 @@ type Config struct {
 	TLSConfig       *tls.Config   `json:"-"`               // TLS Config to use. When set TLS will be negotiated.
 	SlaveOnly       bool          `json:"slaveOnly"`       // Route all commands to slave read-only nodes.
 	Cluster         bool          `json:"cluster"`         // Specifies whether cluster mode be used.
+	Protocol        int           `json:"protocol"`        // Specifies the RESP version (Protocol 2 or 3.)
 }
 
 const (
@@ -102,6 +103,9 @@ func ConfigFromMap(m map[string]interface{}) (config *Config, err error) {
 	if config.MaxConnLifetime < time.Second {
 		config.MaxConnLifetime = config.MaxConnLifetime * time.Second
 	}
+	if config.Protocol != 2 && config.Protocol != 3 {
+		config.Protocol = 3
+	}
 	return
 }