Add role tag to redis plugins (#1207)

fixes #1203

- Format code

plugins/inputs/redis/redis.go

@@ -74,6 +74,7 @@ var Tracking = map[string]string{
 	"used_cpu_user":               "used_cpu_user",
 	"used_cpu_sys_children":       "used_cpu_sys_children",
 	"used_cpu_user_children":      "used_cpu_user_children",
+	"role": "role",
 }
 
 var ErrProtocolError = errors.New("redis protocol error")
@@ -206,6 +207,11 @@ func gatherInfoOutput(
 			keyspace_misses = ival
 		}
 
+		if name == "role" {
+			tags["role"] = val
+			continue
+		}
+
 		if err == nil {
 			fields[metric] = ival
 			continue