Node.js应用程序中的SequelizeConnectionError

我有一个奇怪的问题，不知道问题出在什么地方.我将不胜感激.

I have strange problem and don't know in what place is the problem. I will be grateful for any help.

我有 Node.js 应用程序，该应用程序在本地Windows 10计算机上运行良好.我在CentOS服务器中的 Docker 中成功运行了该应用程序.该应用程序可用于远程MySQL和PostgreSQL数据库.几天正常工作，但是今天我注意到我有错误.应用程序无法再连接到远程MySQL数据库.同时，如果我在本地计算机上运行应用程序或通过DBeaver/dbForge工具进行连接，则可以毫无问题地连接到该远程MySQL数据库.

I have Node.js application which works fine in local windows 10 computer. I run this application successfully in Docker which is in CentOS server. This application works with remote MySQL and PostgreSQL databases. It worked correctly several days but yestoday I notice that I have error. Application can't connect to remote MySQL database anymore. In the same time I can connect to that remote MySQL database without any problem if I run application in my local computer or connect by DBeaver/dbForge tool.

MySQL.js :

const Sequelize = require('sequelize');

const sequelize = new Sequelize('database_name', 'username', 'password', {
    host: 'host',
    dialect: 'mysql'
});

sequelize.authenticate().then(() => {
    console.log('Connection to database has been established successfully.');
}).catch(err => {
    console.error('Unable to connect to database:', err);
});

module.exports = sequelize;

routes.js :

const express = require('express');

const router = express.Router();

const sequelize = require('../configurations/MySQL');
const Sequelize = require('sequelize');

const passport = require('passport');
require('../configurations/password')(passport);

router.post('/search_by_name', passport.authenticate('jwt', {session: false}, null), function(req, res) {
    const token = getToken(req.headers);
    if (token) {
        sequelize.query("LONG SQL QUERY", {
            replacements: {
                name: req.body.name,
            },
            type: Sequelize.QueryTypes.SELECT
        }).then((locations) => {
            res.status(200).send(locations)
        }).catch((error) => {
            res.status(400).send(error);
        });
    } else {
        return res.status(401).send({
            status: false,
            description: "Unauthorized"
        });
    }
});

您可以看到，我使用 sequelize 库将应用程序连接到远程MySQL数据库.我用于连接到远程PostgreSQL数据库的库相同.正如我之前所说，只有当我尝试连接到Docker中的远程MySQL数据库时，错误才会发生.Docker中的PostgreSQL连接没有错误.Docker/网络内部是否可能出现此问题?

As you can see I use sequelize library to connect application to remote MySQL database. The same library I use to connect to remote PostgreSQL database. As I said before error happens only when I try to connect to remote MySQL database in Docker. There is no error with PostgreSQL connection in Docker. Is it possible that problem inside Docker/network?

依赖项:

"sequelize": "^4.42.0"
"mysql2": "^1.6.4"

我还认为问题的原因可能是因为大量的池/连接，而续集库不会自动关闭它们.因此，我多次重启dockerсontainer以期确认理论.不幸的是，错误并没有消失.

I also thought that the reason of the problem can be because of much pools/connections and sequelize library don't close them automatically. For thats why I restarted docker сontainer several times hoping to confirm the theory. Unfortunately the error do not disappear.

您如何看待?

错误:

Unable to connect to the database: { SequelizeConnectionError: connect ETIMEDOUT
    at Utils.Promise.tap.then.catch.err (/node_modules/sequelize/lib/dialects/mysql/connection-manager.js:149:19)
    at tryCatcher (/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/node_modules/bluebird/js/release/promise.js:512:31)
    at Promise._settlePromise (/node_modules/bluebird/js/release/promise.js:569:18)
    at Promise._settlePromise0 (/node_modules/bluebird/js/release/promise.js:614:10)
    at Promise._settlePromises (/node_modules/bluebird/js/release/promise.js:690:18)
    at _drainQueueStep (/node_modules/bluebird/js/release/async.js:138:12)
    at _drainQueue (/node_modules/bluebird/js/release/async.js:131:9)
    at Async._drainQueues (/node_modules/bluebird/js/release/async.js:147:5)
    at Immediate.Async.drainQueues [as _onImmediate] (/node_modules/bluebird/js/release/async.js:17:14)
    at processImmediate (timers.js:632:19)
  name: 'SequelizeConnectionError',
  parent:
   { Error: connect ETIMEDOUT
       at Connection._handleTimeoutError (/node_modules/mysql2/lib/connection.js:173:17)
       at listOnTimeout (timers.js:324:15)
       at processTimers (timers.js:268:5)
     errorno: 'ETIMEDOUT',
     code: 'ETIMEDOUT',
     syscall: 'connect',
     fatal: true },
  original:
   { Error: connect ETIMEDOUT
       at Connection._handleTimeoutError (/node_modules/mysql2/lib/connection.js:173:17)
       at listOnTimeout (timers.js:324:15)
       at processTimers (timers.js:268:5)
     errorno: 'ETIMEDOUT',
     code: 'ETIMEDOUT',
     syscall: 'connect',
     fatal: true }}