Reproduce MySQL error: The server closed the connection (node.js)

Question

I\'m trying to reproduce a MySQL error I\'m seeing in my node.js app on EC2 with the node mysql library:

Connection lost: The server closed the connec

Answer 1

Using generic-pool, I wrote something that works locally. I guess I'll test it and see if it doesn't crash in bizarre manner on the server side.

// Test node connection pool stuff

// Create a MySQL connection pool with
// a max of 10 connections, a min of 2, and a 30 second max idle time
var poolModule = require('generic-pool');
var pool = poolModule.Pool({
    name     : 'mysql',
    create   : function(callback) {
        var Client = require('mysql').Client; // use node-mysql library in all it's dubious glory
        var c = new Client();
        c.user     = 'root';
        c.password = 'xxx';
        c.database = 'test';
        c.on('close', function (err) {
          console.log('mysqldb conn close');
        });
        c.on('error', function (err) {
          console.log('mysqldb error: ' + err);
        });

        // parameter order: err, resource
        // new in 1.0.6
        callback(null, c);
    },
    destroy  : function(client) { client.end(); },
    max      : 10,
    // optional. if you set this, make sure to drain() (see step 3)
    min      : 2, 
    // specifies how long a resource can stay idle in pool before being removed
    idleTimeoutMillis : 30000,
     // if true, logs via console.log - can also be a function
    log : true 
});

var http = require('http');
http.createServer(function (req, res) {

  // Get db conn
  pool.acquire(function(err, client) {
      if (err) {
          // handle error - this is generally the err from your
          // factory.create function 
          console.log('pool.acquire err: ' + err);
          res.writeHead(500, {'Content-Type': 'application/json'});
          out = {
            err: err
          }
          res.end(JSON.stringify(out));
      }
      else {
          client.query("select * from foo", [], function(err, results) {

              if(err){
                res.writeHead(500, {'Content-Type': 'application/json'});
                out = {
                  err: err
                }
                res.end(JSON.stringify(out));
              } else {
                res.writeHead(500, {'Content-Type': 'application/json'});
                out = {
                  results: results
                }
                res.end(JSON.stringify(out));
              }


              // return object back to pool
              pool.release(client);
          });
      }
  });
}).listen(9615);

Pretty please don't die at 4am for no apparent reason!