Fix/rolling logger

logger/README.md

@@ -40,10 +40,11 @@ logger.SetLoggerLevel("warn")
 
 #### output to file
 
-Add the file item under the logger option in the configuration file
+Set `appender: file` and add the file item under the logger option in the configuration file. When the sample is run from `logger/rolling`, the relative file name below is created as `logger/rolling/logs.log`. Use `appender: console,file` if you want the same log records to be written to both console and file.
 
 ```yaml
   logger:
+    appender: file
     file:
       name: logs.log
       max-size: 1

logger/README_zh.md

@@ -40,10 +40,11 @@ logger.SetLoggerLevel("warn")
 
 #### 输出到文件
 
-在配置文件中的 logger 选项下添加 file 项
+在配置文件中的 logger 选项下设置 `appender: file` 并添加 file 项。从 `logger/rolling` 目录运行样例时，下面的相对文件名会生成到 `logger/rolling/logs.log`。如果希望同一批日志同时输出到控制台和文件，可使用 `appender: console,file`。
 
 ```yaml
   logger:
+    appender: file
     file:
       name: logs.log
       max-size: 1

logger/rolling/cmd/main.go

@@ -44,6 +44,7 @@ func main() {
 			logger.Info("hello dubbogo this is info log")
 			logger.Debug("hello dubbogo this is debug log")
 			logger.Warn("hello dubbogo this is warn log")
+			time.Sleep(time.Second * 1)
 		}
 	}
 }

logger/rolling/conf/dubbogo.yml

@@ -4,6 +4,7 @@ dubbo:
       name: tri
       port: 20000
   logger:
+    appender: file
     file:
       name: logs.log
       max-size: 1