我得到以下警告:

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace: 
    at EventEmitter.<anonymous> (events.js:139:15)
    at EventEmitter.<anonymous> (node.js:385:29)
    at Server.<anonymous> (server.js:20:17)
    at Server.emit (events.js:70:17)
    at HTTPParser.onIncoming (http.js:1514:12)
    at HTTPParser.onHeadersComplete (http.js:102:31)
    at Socket.ondata (http.js:1410:22)
    at TCP.onread (net.js:354:27)

我在server.js中写了这样的代码:

http.createServer(
    function (req, res) { ... }).listen(3013);

如何解决这个问题?


当前回答

添加EventEmitter.defaultMaxListeners = <MaxNumberOfClients>到node_modules\loop -datasource-juggler\lib\datasource.js修复了可能的问题:)

其他回答

有时,这些警告发生在我们没有做过的事情,而是我们忘记做的事情!

当我用npm安装dotenv包时遇到了这个警告,但在我在应用程序开始添加require('dotenv').load()语句之前就被打断了。当我回到项目时,我开始得到“可能的EventEmitter内存泄漏检测到”警告。

我以为问题出在我做了什么,而不是我没做什么!

一旦我发现了我的疏忽并添加了require语句,内存泄漏警告就清除了。

公认的答案提供了如何增加限制的语义,但正如@voltrevo指出的那样,警告是有原因的,您的代码可能存在错误。

考虑以下有bug的代码:

//Assume Logger is a module that emits errors
var Logger = require('./Logger.js');

for (var i = 0; i < 11; i++) {
    //BUG: This will cause the warning
    //As the event listener is added in a loop
    Logger.on('error', function (err) {
        console.log('error writing log: ' + err)
    });

    Logger.writeLog('Hello');
}

现在观察添加监听器的正确方法:

//Good: event listener is not in a loop
Logger.on('error', function (err) {
    console.log('error writing log: ' + err)
});

for (var i = 0; i < 11; i++) {
    Logger.writeLog('Hello');
}

在更改maxListeners之前搜索代码中的类似问题(在其他答案中有解释)

节点版本号:v11.10.1

来自堆栈跟踪的警告消息:

process.on('warning', e => console.warn(e.stack));
(node:17905) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 wakeup listeners added. Use emitter.setMaxListeners() to increase limit
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 wakeup listeners added. Use emitter.setMaxListeners() to increase limit
    at _addListener (events.js:255:17)
    at Connection.addListener (events.js:271:10)
    at Connection.Readable.on (_stream_readable.js:826:35)
    at Connection.once (events.js:300:8)
    at Connection._send (/var/www/html/fleet-node-api/node_modules/http2/lib/protocol/connection.js:355:10)
    at processImmediate (timers.js:637:19)
    at process.topLevelDomainCallback (domain.js:126:23)

在搜索github问题,文档和创建类似的事件发射器内存泄漏后,由于node-apn模块用于iOS推送通知,观察到此问题。

这就解决了问题:

您应该为每个进程只创建一个Provider 您拥有的证书/密钥对。您不需要创建一个新的 每个通知的提供者。如果你只是发送通知 一个应用程序,那么就不需要一个以上的提供商。 如果你经常在你的应用程序中创建Provider实例,make 当你使用完每个提供者时,一定要调用provider .shutdown() 释放其资源和内存。

每次发送通知时,我都在创建提供者对象,并期望gc将其清除。

You said you are using process.on('uncaughtException', callback); Where are you executing this statement? Is it within the callback passed to http.createServer?If yes, different copy of the same callback will get attached to the uncaughtException event upon each new request, because the function (req, res) { ... } gets executed everytime a new request comes in and so will the statement process.on('uncaughtException', callback);Note that the process object is global to all your requests and adding listeners to its event everytime a new request comes in will not make any sense. You might not want such kind of behaviour. In case you want to attach a new listener for each new request, you should remove all previous listeners attached to the event as they no longer would be required using: process.removeAllListeners('uncaughtException');

我们团队对此的解决方案是从.npmrc中删除注册表路径。rc文件中有两个路径别名,其中一个指向已弃用的Artifactory实例。

这个错误与我们的应用程序的实际代码无关,而是与我们的开发环境有关。