node.js - NodeJS : warning: possible EventEmitter memory leak detected. 添加了 11 个监听器。使用 emitter.setMaxListeners() 增加限制

Question

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)

Answer 1

我认为问题在于当您不再需要监听器时，您没有移除它们。完成后，您需要使用“schild.removeListener('exit', function)”或“schild.removeAllListeners('exit')”。

参见: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 个监听器，在这种情况下，您应该使用“schild.setMaxListeners(0)”(0 表示无限制)

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

希望对您有所帮助!