当监听process.env.PORT时，heroku应用程序崩溃 [英] heroku app crash when listening on process.env.PORT

问题描述

当我在heroku上部署它时:

When i deploy this on heroku :

app.js

var port = process.env.PORT || 8080;

app.listen(port, function(){
    console.log("Listening on port : " + port);
});

我得到了错误日志:

2014-11-08T18:05:34.300115+00:00 app[web.1]: events.js:72
2014-11-08T18:05:34.300402+00:00 app[web.1]:         throw er; // Unhandled 'error' event
2014-11-08T18:05:34.300404+00:00 app[web.1]:               ^
2014-11-08T18:05:34.303599+00:00 app[web.1]: Error: listen EADDRINUSE
2014-11-08T18:05:34.303605+00:00 app[web.1]:     at errnoException (net.js:904:11)
2014-11-08T18:05:34.303607+00:00 app[web.1]:     at Server._listen2 (net.js:1042:14)
2014-11-08T18:05:34.303608+00:00 app[web.1]:     at listen (net.js:1064:10)
2014-11-08T18:05:34.303610+00:00 app[web.1]:     at Server.listen (net.js:1138:5)
2014-11-08T18:05:34.303628+00:00 app[web.1]:     at Function.app.listen (/app/node_modules/express/lib/application.js:556:24)
2014-11-08T18:05:34.303629+00:00 app[web.1]:     at Object.<anonymous> (/app/bin/www:7:18)
2014-11-08T18:05:34.303630+00:00 app[web.1]:     at Module._compile (module.js:456:26)
2014-11-08T18:05:34.303632+00:00 app[web.1]:     at Object.Module._extensions..js (module.js:474:10)
2014-11-08T18:05:34.303633+00:00 app[web.1]:     at Module.load (module.js:356:32)
2014-11-08T18:05:34.303635+00:00 app[web.1]:     at Function.Module._load (module.js:312:12)

但是当我直接在8080端口上监听时，它可以工作，而且我不明白为什么:

but when i listen directly on port 8080 it work, and i cant understand why :

var port = 8080;
    app.listen(port, function(){
        console.log("Listening on port : " + port); //it work
    });

我刚刚开始使用nodejs，但我真的不明白为什么它会崩溃.

I have just started using nodejs and I don't really understand why it crashes.

有人可以解释其原因或如何对其进行调试"吗?

Could someone either explain the cause of this or how to "debug" this?

谢谢！

推荐答案

好的，问题在于express-generator创建了一个包含以下内容的/bin/www文件:

OK, the problem was that express-generator create a /bin/www file that contain :

#!/usr/bin/env node
var debug = require('debug')('toto');
var app = require('../app');

app.set('port', process.env.PORT || 3000);

var server = app.listen(app.get('port'), function() {
  debug('Express server listening on port ' + server.address().port);
});

这就是为什么该端口已被使用的原因.

Thats why the port was already used.

谢谢

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