NodeJS：警告：检测到可能的 EventEmitter 内存泄漏。增加了 11 位听众。使用emitter.setMaxListeners() 增加限制答案

【问题标题】：NodeJS : warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limitNodeJS：警告：检测到可能的 EventEmitter 内存泄漏。增加了 11 位听众。使用emitter.setMaxListeners() 增加限制
【发布时间】：2012-12-08 14:59:08
【问题描述】：

我有以下代码：

var schild = spawn('script.sh', ["process1", "process2"]);
        schild.stderr.on('data', function (data) {
                        logger.info('stderr: ' + data);
        });

        schild.on('exit', function (code) {
          logger.info('child process exited with code ' + code);
        });

        schild.stdout.on('data', function (data) {
           logger.info('Data ' + data);
        });

当我运行代码时出现以下错误：

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
    at EventEmitter.addListener (events.js:175:15)
    at EventEmitter.once (events.js:196:8)
    at Transport.logException (/x/home/prakash/src/node_modules/winston/lib/winston/transports/transport.js:118:8)
    at logAndWait (/x/home/prakash/src/node_modules/winston/lib/winston/logger.js:613:15)
    at async.forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:86:13)
    at Array.forEach (native)
    at _forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:26:24)
    at Object.async.forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:85:9)
    at Logger._uncaughtException (/x/home/prakash/src/node_modules/winston/lib/winston/logger.js:636:9)
    at process.EventEmitter.emit (events.js:126:20)
(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
    at EventEmitter.addListener (events.js:175:15)
    at EventEmitter.once (events.js:196:8)
    at Transport.logException (/x/home/prakash/src/node_modules/winston/lib/winston/transports/transport.js:117:8)
    at logAndWait (/x/home/prakash/src/node_modules/winston/lib/winston/logger.js:613:15)
    at async.forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:86:13)
    at Array.forEach (native)
    at _forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:26:24)
    at Object.async.forEach (/x/home/prakash/src/node_modules/winston/node_modules/async/lib/async.js:85:9)
    at Logger._uncaughtException (/x/home/prakash/src/node_modules/winston/lib/winston/logger.js:636:9)
    at process.EventEmitter.emit (events.js:126:20)

【问题讨论】：

这只是一个警告，而不是错误。见：stackoverflow.com/questions/9768444/…
possible EventEmitter memory leak detected的可能重复

标签： node.js

【解决方案1】：

我认为问题在于，当您不再需要侦听器时，您并没有移除它们。完成后，您需要使用 'schild.removeListener('exit', function)' 或 'schild.removeAllListeners('exit')'。

见：http://nodejs.org/api/events.html#events_emitter_removelistener_event_listener

当然，在某些情况下您需要拥有超过 10 个侦听器，在这种情况下您应该使用 'schild.setMaxListeners(0)'（0 表示无限制）

见：http://nodejs.org/api/events.html#events_emitter_setmaxlisteners_n

希望对你有帮助！

【讨论】：