Node.js ssh2 tunnel keep alive and execute mysql queries

Question

I am implementing a rest api using node.js that uses ssh2 package tunneling to connect to the remote mysql database. Here is the code I am using to connect via ssh and to execute query

executeQuery : function(query, callback) {
        var sshConnected = false;
        var connection = require('ssh2').Client();
        var server = require('net').createServer(function(sock) {
            if (!sshConnected) return sock.end();
            connection.forwardOut(
                '127.0.0.1',
                sock.remotePort,
                '127.0.0.1',
                3306,
                function (err, stream) {
                    if (err) return sock.end();
                    stream.pipe(sock).pipe(stream);
                });
        });
        connection.on('ready', function() {
            console.log('Client :: ready');
            sshConnected = true;
            server.listen(3306);
            var sqlconn = require('mysql').createConnection(config.dbOrg);
            sqlconn.connect(function (conError) {
                if (!conError) {
                    console.log(query);
                    sqlconn.query({sql: query.sql, values: query.values}, function (qError, results, fields) {
                        callback(qError, results, fields);
                    });
                } else {
                    callback(response.dbError, null, null);
                }
                server.close();
            });
        }).connect(config.sshConfig);

However, as you can see it is not very efficient.

For every new query, I am establishing the connection again, starting the TCP Server and stopping it after query. Each query takes roughly around 3-4s which is really bad. Any approaches keeping both the ssh connection and the tcp server alive to execute queries as they arrive, would be of great help. Thanks!

score 7 · Accepted Answer · answered Apr 13 '16 at 19:54

In the case of using the database driver directly, if you use mysql2 instead of mysql, you can actually pass the ssh forwarded stream as the underlying connection to be used by the database driver. This will allow you to skip having to create an additional server that listens for incoming connections to be tunneled. So you can do something like this instead:

var mysql = require('mysql2');
var Client = require('ssh2').Client;

var ssh = new Client();
ssh.on('ready', function() {
  ssh.forwardOut(
    '127.0.0.1',
    12345,
    '127.0.0.1',
    3306,
    function (err, stream) {
      if (err) throw err;
      var sql = mysql.createConnection({
        user: 'foo',
        database: 'test',
        stream: stream // <--- this is the important part
      });
      // use sql connection as usual
  });
}).connect({
  // ssh connection config ...
});

Node.js ssh2 tunnel keep alive and execute mysql queries

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