Winston - MaxListenersExceededWarning：检测到可能的 EventEmitter 内存泄漏

Question

在 Winston-daily-rotate-file 包中使用文件日志记录时出现以下错误，代码与 Winston 控制台日志记录配合良好，

  MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit
        at _addListener (events.js:256:17)
        at DailyRotateFile.addListener (events.js:272:10)
        at DailyRotateFile.once (events.js:301:8)
        at asyncForEach (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:217:17)
        at /home/ubuntumachine/Desktop/project/node_modules/async/internal/withoutIndex.js:9:16
        at eachOfArrayLike (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:65:9)
        at exports.default (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:9:5)
        at eachLimit (/home/ubuntumachine/Desktop/project/node_modules/async/forEach.js:80:24)
        at ExceptionHandler._uncaughtException (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:203:5)
        at process.emit (events.js:198:13)
    (node:20805) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 finish listeners added. Use emitter.setMaxListeners() to increase limit
        at _addListener (events.js:256:17)
        at DailyRotateFile.addListener (events.js:272:10)
        at DailyRotateFile.once (events.js:301:8)
        at asyncForEach (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:216:17)
        at /home/ubuntumachine/Desktop/project/node_modules/async/internal/withoutIndex.js:9:16
        at eachOfArrayLike (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:65:9)
        at exports.default (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:9:5)
        at eachLimit (/home/ubuntumachine/Desktop/project/node_modules/async/forEach.js:80:24)
        at ExceptionHandler._uncaughtException (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:203:5)
        at process.emit (events.js:198:13)
    (node:20805) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 31 error listeners added. Use emitter.setMaxListeners() to increase limit
        at _addListener (events.js:256:17)
        at Console.addListener (events.js:272:10)
        at Console.once (events.js:301:8)
        at asyncForEach (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:217:17)
        at /home/ubuntumachine/Desktop/project/node_modules/async/internal/withoutIndex.js:9:16
        at eachOfArrayLike (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:65:9)
        at exports.default (/home/ubuntumachine/Desktop/project/node_modules/async/eachOf.js:9:5)
        at eachLimit (/home/ubuntumachine/Desktop/project/node_modules/async/forEach.js:80:24)
        at ExceptionHandler._uncaughtException (/home/ubuntumachine/Desktop/project/node_modules/winston/lib/winston/exception-handler.js:203:5)
        at process.emit (events.js:198:13)

尝试将最大侦听器设置为无穷大，

const EventEmitter = require('events');
const emitter = new EventEmitter();
emitter.setMaxListeners(Infinity);

仍然面临同样的问题。

Answer 1

我遇到了一个相关的案例，标题中提到了警告，所以只是与可能进入此主题的其他人分享我的调查见解：

• 弹出这个警告的原因是什么？好吧，这个相关线程中的评论很好地解释了这一点。简而言之：广泛使用交通工具。
• 如何禁用警告？我发现很少有地方（比如这个）提供更新最大侦听器。他们使用process.setMaxListeners(0);，这与问题中使用的不同。
• 应该禁用警告吗？我倾向于不（正如本线程的第一条评论中所解释的）。
• 为什么clear()有帮助？好吧，我没有读太多相关内容，但根据文档- 它删除了所有传输。
• 在其他什么情况下可能会出现此错误？- 当使用传输创建大量记录器实例时。我就是这种情况。

Answer 2

winstonLoggerInstance.clear()我遇到了同样的问题，当我完成记录器后，它通过调用解决了。clear()清除所有传输。