node.js - nodejs项目在heroku上跑失败，打印错误代码code=H10(内容附详细log)

Question

heroku上web dynos是1，数据库用的是heroku中的clearDB:ignite，connection限定是10
项目在foreman start没有出现问题

最开始，项目在heroku上跑失败，然后看自己项目的代码，发现数据库配置好后，就conn.connect(),并没有做任何异常处理，于是我对数据库连接做的这样的修改：

function handleDisconnect(){

    conn = mysql.createConnection(db_config);
    conn.connect(function (err){
        if(err){
            console.log('error when connecting to db:', err);
            setTimeout(handleDisconnect, 2000);
        }
    });

    conn.on('error', function (err){
        console.log('db error', err);
        if(err.code === 'PROTOCOL_CONNECTION_LOST'){
            handleDisconnect();
        }
        else{
            throw err;
        }
    });
} 

var db_config = ({
    connectionLimit: 10,
    host: '***',
    user: '***',
    password: '***',
    database: '***'   //
});

但是还是没跑成功，贴出heroku logs

2014-11-18T13:40:25.516150+00:00 app[web.1]:   code: 'ER_USER_LIMIT_REACHED',
2014-11-18T13:40:25.516156+00:00 app[web.1]:   fatal: true }
2014-11-18T13:40:25.747226+00:00 app[web.1]:   code: 'ER_USER_LIMIT_REACHED',
2014-11-18T13:40:25.747228+00:00 app[web.1]:   errno: 1226,
2014-11-18T13:40:25.747231+00:00 app[web.1]:   sqlState: '42000',
2014-11-18T13:40:25.747233+00:00 app[web.1]:   fatal: true }
2014-11-18T13:40:25.817449+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2014-11-18T13:40:25.817664+00:00 heroku[web.1]: Stopping process with SIGKILL
2014-11-18T13:40:26.637882+00:00 heroku[web.1]: Process exited with status 137
2014-11-18T13:40:26.650174+00:00 heroku[web.1]: State changed from starting to crashed
2014-11-18T13:43:19.620511+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=943cb29f-4018-47bd-abed-e8528f34463c fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T13:50:48+00:00 heroku[slug-compiler]: Slug compilation started
2014-11-18T13:50:53+00:00 heroku[slug-compiler]: Slug compilation finished
2014-11-18T13:50:53.134832+00:00 heroku[api]: Release v27 created by ybooty0@gmail.com
2014-11-18T13:50:53.134803+00:00 heroku[api]: Deploy 276bd38 by ybooty0@gmail.com
2014-11-18T13:50:53.387565+00:00 heroku[web.1]: State changed from crashed to starting
2014-11-18T13:50:55.370783+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T13:50:56.352391+00:00 app[web.1]: listen port:3000
2014-11-18T13:51:09.808436+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T13:51:10.966893+00:00 app[web.1]: listen port:3000
2014-11-18T13:51:24.749168+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2014-11-18T13:51:26.002004+00:00 heroku[web.1]: Process exited with status 143
2014-11-18T13:52:01.559470+00:00 app[web.1]: db error { [Error: Connection lost: The server closed the connection.] fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
2014-11-18T13:52:10.009461+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2014-11-18T13:52:10.011140+00:00 heroku[web.1]: Stopping process with SIGKILL
2014-11-18T13:52:10.847913+00:00 heroku[web.1]: Process exited with status 137
2014-11-18T13:52:10.930299+00:00 heroku[web.1]: State changed from starting to crashed
2014-11-18T13:52:10.931028+00:00 heroku[web.1]: State changed from crashed to starting
2014-11-18T13:52:13.429078+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T13:52:14.743426+00:00 app[web.1]: listen port:3000
2014-11-18T13:53:01.585187+00:00 app[web.1]: db error { [Error: Connection lost: The server closed the connection.] fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
2014-11-18T13:53:13.738410+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2014-11-18T13:53:13.738618+00:00 heroku[web.1]: Stopping process with SIGKILL
2014-11-18T13:53:14.460601+00:00 heroku[web.1]: Process exited with status 137
2014-11-18T13:53:14.471170+00:00 heroku[web.1]: State changed from starting to crashed
2014-11-18T13:53:15.702820+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=5929aba6-9e68-4364-a01b-d88276556fb5 fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T13:53:16.167433+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=224340c2-fb70-43e7-ac7d-fe48c0caa177 fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T13:53:30.184663+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=629c31ae-a003-4f71-aa57-5c48bb0834f1 fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T13:55:53+00:00 heroku[slug-compiler]: Slug compilation started
2014-11-18T13:55:59+00:00 heroku[slug-compiler]: Slug compilation finished
2014-11-18T13:55:59.596193+00:00 heroku[api]: Deploy 524c1cc by ybooty0@gmail.com
2014-11-18T13:55:59.596193+00:00 heroku[api]: Release v28 created by ybooty0@gmail.com
2014-11-18T13:55:59.803424+00:00 heroku[web.1]: State changed from crashed to starting
2014-11-18T13:56:01.628121+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T13:56:02.691273+00:00 app[web.1]: listen
2014-11-18T13:56:47.721732+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T13:56:48.569681+00:00 app[web.1]: listen
2014-11-18T13:56:48.268846+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2014-11-18T13:56:49.626232+00:00 heroku[web.1]: Process exited with status 143
2014-11-18T13:57:48.201967+00:00 heroku[web.1]: Stopping process with SIGKILL
2014-11-18T13:57:48.201717+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2014-11-18T13:57:48.993016+00:00 heroku[web.1]: Process exited with status 137
2014-11-18T13:57:49.000428+00:00 heroku[web.1]: State changed from starting to crashed
2014-11-18T13:57:51.148935+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=b0395099-1e7d-4142-8398-9450fa927c4f fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T14:04:57.673963+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=00fac694-6521-4005-8f0e-391d26ae2990 fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T14:09:57.102273+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=haixiu-web.herokuapp.com request_id=55e99f5a-010a-428f-a408-d5c42ff46a6e fwd="106.187.36.10" dyno= connect= service= status=503 bytes=
2014-11-18T14:12:07.036105+00:00 heroku[web.1]: State changed from crashed to starting
2014-11-18T14:12:09.042086+00:00 heroku[web.1]: Starting process with command `node index.js`
2014-11-18T14:12:10.204534+00:00 app[web.1]: listen
2014-11-18T14:13:01.171295+00:00 app[web.1]: db error { [Error: Connection lost: The server closed the connection.] fatal: true, code: 'PROTOCOL_CONNECTION_LOST' }
2014-11-18T14:13:09.515324+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2014-11-18T14:13:09.515553+00:00 heroku[web.1]: Stopping process with SIGKILL
2014-11-18T14:13:10.240589+00:00 heroku[web.1]: Process exited with status 137
2014-11-18T14:13:10.246122+00:00 heroku[web.1]: State changed from starting to crashed

附带说明，我做的是一个nodejs的爬虫项目，数据库中有个字段存储着爬下图片的链接；而web dyno在heroku上是这样解释 : A web dyno runs your code and responds to HTTP requests. More dynos provide more concurrency. 图片加载的时候会向原网站发送请求，这里是不是又有可能是项目失败的原因？

谦求解答，如何提问的方式有哪里不好，也请指出

Answer 1

问题目前已经解决，分享下自己的解决过程：
首先自己找到问题的根源是 ： cleardb:ignite 这个免费的addon 提供的connections只有10，而在mysql中建立的链接，如果不用pool，在10次connect后就无法在建立链接了。
所以问题就这样解决了，用pool，在每一次connect后都release掉，让它回到pool中可以重用。
可以参考npm myslq中pool如何使用：https://github.com/felixge/node-mysql