Express.js应用程序没有使用server.close（）干净地关闭

I'm trying to properly close a MongoDB connection when the app is shut down. Here is the code:

我正在尝试在关闭应用程序时正确关闭MongoDB连接。这是代码:

var express = require('express')
  , http = require('http')
  , mongoose = require('mongoose')
  , path = require('path');

var app = express();

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

mongoose.connect('mongodb://localhost/test');

// some post and get handlers etc. (removed for shorter output)

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

function cleanup () {
    server.close(function () {
        console.log("Closed out remaining connections.");
        mongoose.connection.close();
        process.exit();
    });

    setTimeout( function () {
        console.error("Could not close connections in time, forcing shut down");
        process.exit(1);
    }, 30*1000);
}

process.on('SIGINT', cleanup);
process.on('SIGTERM', cleanup);

All is well and works when the app starts for the first time. When I hit Ctrl-c right after it has started, it cleanly shuts down with the Closed out remaining connections. message. However, as soon as the app interacts with the database or even serves a static page, and I try to shut it down after that, it exits with the following error:

当应用程序第一次启动时,一切都很顺利。当我在启动后立即按下Ctrl-c时,它会在关闭的剩余连接中干净地关闭。信息。但是,只要应用程序与数据库交互或甚至提供静态页面,我尝试在此之后将其关闭,它将退出并显示以下错误:

net.js:1225
    throw new Error('Not running');
          ^
Error: Not running
    at Server.close (net.js:1225:11)
    at process.cleanup (<...>/app.js:77:12)
    at process.EventEmitter.emit (events.js:92:17)
    at Signal.wrap.onsignal (node.js:756:46)
22 Aug 15:15:28 - [nodemon] exiting

Any ideas what is causing this error and how I could fix it?

是什么原因造成了这个错误以及我如何解决它?

3 个解决方案

#1

When server.close is called, there are two properties that are checked.

调用server.close时,会检查两个属性。

   handle<tcp handle>
   connections

Responsible code fragment of server.close responsible for this error;

server.close的负责代码片段负责此错误;

  if (!this._handle) {
    // Throw error. Follows net_legacy behaviour.
    throw new Error('Not running');
  }

Only if handle===null and connections ===0 that the callback passed to close is called.

只有当handle === null和connections === 0时,才会调用传递给close的回调。

Case : Server is started and sent the signal with no serving.

案例:服务器启动并发送信号,没有服务。

Before close is called;

在关闭前调用;

  handle === TCP handle.
  connection===0;

After close handle===null; connection===0;

关闭句柄后=== null;连接=== 0;

The callback gets called.

调用回调。

Case : Server is started and sent the signal after a request server.

案例:服务器启动并在请求服务器之后发送信号。

Before close is called;

在关闭前调用;

  handle === TCP.handle;
  connection===1;

After close handle === null; connection===1;

关闭句柄后=== null;连接=== 1;

No callback is fired.

没有回调。

Second time when you press ctrl-c

第二次按ctrl-c

Before close is called;

在关闭前调用;

  handle === null;
  connection===1;

since handle===null , the check throws the error you are seeing.

因为句柄=== null,检查会抛出你看到的错误。

#2

The reason your server has open connections is because you are sending Connection: keep-alive header.

您的服务器打开连接的原因是您发送Connection:keep-alive标头。

Morgan's answer closes all the connections on the server cleanly, disconnecting all of the clients.

Morgan的回答干净地关闭了服务器上的所有连接,断开了所有客户端的连接。

If you are just testing your application and want to shut it down cleanly before/after tests I recommend sending Connection: close header and server.close() will work as expected.

如果您只是测试您的应用程序并希望在测试之前/之后干净地关闭它,我建议发送Connection:close header和server.close()将按预期工作。

#3

I don't think setting server._connections = 0 actually closes the connection. It just satisfies the conditions to get your callback executed.

我不认为设置server._connections = 0实际上会关闭连接。它只是满足了执行回调的条件。

You might want to try something like this:

您可能想尝试这样的事情:

// Everything else how you had it before ...

var sockets = [];

server.on('connection', function(socket) {
  sockets.push(socket);
});

function cleanup () {
  server.close(function () {
    console.log("Closed out remaining connections.");
     // mongoose.connection.close(); Might want to comment this out
    process.exit();
  });

  // Add this part to manually destroy all the connections.
  sockets.forEach(function(socket) {
    socket.destroy();
  });

  // setTimeout() ...
}