MySql Connection pool & Auto reconnection

mysql wrapper class

/*
  use ver 2
  provide:
    connection pool
    auto reconnect

  Usage:
    MySql = require 'lib/mysql'  This one
    mysql = new MySql(Config)
    mysql.getConnection().query ...

  Config:
    host
    port
    socketPath
    user
    password
    database
    charset
    typeCast
    pool: pool size > 0
*/

(function() {
  var MySql, allDbs, getDb, helpers, mysql, verbose;

  verbose = 2;

  mysql = require('mysql');

  allDbs = {};

  MySql = (function() {

    function MySql(cfg) {
      this.cfg = cfg != null ? cfg : {};
      this.cs = [];
      this.next = 0;
      this._init();
      allDbs[this.cfg] = this;
    }

    MySql.prototype._init = function() {
      var i, self, _results;
      self = this;
      this._max = this.cfg.pool || 3;
      delete this.cfg.pool;
      if (this._max < 1) {
        this._max = 1;
      }
      i = 0;
      _results = [];
      while (i < this._max) {
        this._conn(i);
        _results.push(i++);
      }
      return _results;
    };

    MySql.prototype._conn = function(i, cb) {
      var c, self;
      self = this;
      self.cs[i] = c = mysql.createConnection(self.cfg);
      console.log("Connecting Mysql " + i);
      return c.connect(function(err) {
        if (err) {
          console.error(err);
          self.cs[i].hasError = err;
          if (cb) {
            cb(null);
          }
          return null;
        }
        self.cs[i].on('close', function(err2) {
          console.log("Mysql Connection Closed " + err2);
          if (err2) {
            console.log(err2);
            self.cs[i].removeAllListeners();
            self.cs[i] = null;
            return setTimeout ((function() { return self._conn(i);}),3000);
          }
        });
        self.cs[i].on('error', function(err3) {
          console.log("Mysql " + i + " Error " + err3);
          if (err3.toString().indexOf('lost')) {
            console.log(err3);
            self.cs[i].removeAllListeners();
            self.cs[i] = null;
            return setTimeout ((function() { return self._conn(i);}),3000);
          } else {
            return self.cs[i].hasError = err3;
          }
        });
        if (verbose) {
          console.log("MySql Connection " + i);
        }
        if (cb) {
          return cb(self.cs[i]);
        }
      });
    };

    MySql.prototype._checkError = function(i, cb) {
      if (this.cs[i].hasError) {
        console.log("Reconnect mysql " + i);
        this.cs[i].removeAllListeners();
        this.cs[i] = null;
        return this._conn(i, cb);
      } else {
        return cb(this.cs[i]);
      }
    };

    MySql.prototype.getConnection = function(cb) {
      if (this.next >= this._max) {
        this.next = 0;
      }
      if (verbose > 1) {
        console.log("MySql pool instance " + this.next);
      }
      if (cb) {
        return this._checkError(this.next++, cb);
      } else {
        return this.cs[this.next++];
      }
    };

    MySql.prototype.query = function() {
      var arg;
      arg = arguments;
      return this.getConnection(function(cs) {
        if (verbose > 1) {
          console.log(arg[0]);
          console.log(arg[1]);
        }
        return cs.query.apply(cs, arg);
      });
    };

    MySql.prototype.format = function(sql, vals, cb) {
      return this.getConnection(function(cs) {
        var s;
        s = cs.format(sql, vals);
        return cb(s);
      });
    };

    return MySql;

  })();

  module.exports.MySql = MySql;

  module.exports.getDb = getDb = function(cfg) {
    if (allDbs[cfg]) {
      return allDbs[cfg];
    } else {
      return new MySql(cfg);
    }
  };

}).call(this);