docs(logger): use async (#1719)

docs/source/en/core/logger.md

@@ -91,7 +91,7 @@ module.exports = app => {
 };
 ```
 
-`app.coreLogger` in app is similar to `ctx.coreLogger` in context: 
+`app.coreLogger` in app is similar to `ctx.coreLogger` in context:
 
 ```js
 // app.js
@@ -180,7 +180,7 @@ exports.logger = {
 
 ### Customized
 
-For common scenarios, **it's unnecessary to create new logger**, because too many loggers will make them hard to be managed for later debugging. 
+For common scenarios, **it's unnecessary to create new logger**, because too many loggers will make them hard to be managed for later debugging.
 
 The logger you create can be declared in config:
 
@@ -225,12 +225,10 @@ class RemoteErrorTransport extends Transport {
     } else {
       log = util.format(...args);
     }
-    const that = this;
-    co(function* () {
-      yield that.options.app.curl('http://url/to/remote/error/log/service/logs', {
-        data: log,
-        method: 'POST',
-      });
+
+    this.options.app.curl('http://url/to/remote/error/log/service/logs', {
+      data: log,
+      method: 'POST',
     }).catch(console.error);
   }
 }

docs/source/zh-cn/core/logger.md

@@ -227,7 +227,6 @@ Transport 是一种传输通道，一个 logger 可包含多个传输通道。
 首先我们定义一个日志的 transport，代表第三方日志服务。
 
 ```js
-const co = require('co');
 const util = require('util');
 const Transport = require('egg-logger').Transport;
 
@@ -242,12 +241,10 @@ class RemoteErrorTransport extends Transport {
     } else {
       log = util.format(...args);
     }
-    const that = this;
-    co(function* () {
-      yield that.options.app.curl('http://url/to/remote/error/log/service/logs', {
-        data: log,
-        method: 'POST',
-      });
+
+    this.options.app.curl('http://url/to/remote/error/log/service/logs', {
+      data: log,
+      method: 'POST',
     }).catch(console.error);
   }
 }
@@ -321,6 +318,4 @@ module.exports = appInfo => {
 
 > 日志同步写入内存，异步每隔一段时间(默认 1 秒)刷盘
 
-
-
 更多详细请参考 [egg-logger](https://github.com/eggjs/egg-logger) 和 [egg-logrotator](https://github.com/eggjs/egg-logrotator)。