dl/lib/client/MySQLCredentialPool.js

DreamLab Libs

/**
 * @overview MySQLCredentialPool
 * @copyright Dreamlab Onet.pl sp. z. o o 2012
 */

var MySQLPool = require('core').client.MySQLPool;
var CredentialsManager = require('../credentials/Manager.js').CredentialsManager;
var mysql = require('mysql');

/**
 * @class MySQLCredentialPool
 * @classdesc MySQL connection pool.
 * @param {String} credential credential key
 * @param {String} identity credential identity
 */
var MySQLCredentialPool = function (credential, identity) {
    var that = this;
    MySQLPool.call(this);
    this._credential = credential;
    this._cm = CredentialsManager.factory(identity);
    this._cm.addEventListener(CredentialsManager.Event.LOADED, credential, function (data) {
        that._createSpareClients(data.data);
    });
    this._cm.addEventListener(CredentialsManager.Event.ERROR, credential, function (data) {
        console.error('CREDENTIAL ERROR: ' + credential +
            '. Error while receiving credential data for MySQLPool',
            JSON.stringify(data.data));
        setTimeout(function () {
            console.info('CREDENTIAL INFO: getting credential -> ' +
                credential);
            that._cm.renewCredential(credential);
        }, 500);
    });
};

MySQLCredentialPool.prototype = Object.create(MySQLPool.prototype);

/**
 * Create clients
 * @method
 */
MySQLCredentialPool.prototype.connect = function () {
    this._cm.getCredential(this._credential);
};

/**
 * Create spare clients
 * @method
 * @param {Object} data
 */
MySQLCredentialPool.prototype._createSpareClients = function (data) {
    console.info('MySQLCredentialPool>MySQL create connections: %s', JSON.stringify(data));

    var randIndex = Math.round(Math.random() * (data.hosts.length - 1)),
        host = data.hosts[randIndex].host,
        port = data.hosts[randIndex].port,
        max_connections = data.max_connections || 1;

    console.info('MySQLCredentialPool>MySQL connecting to: %s:%d', host, port);
    
    var create_connections = max_connections - this.getKnownLength();

    console.info('MySQLCredentialPool>MySQL connections', (create_connections > 0 ? 'shortage' : 'overhead'), create_connections);
    var connectionOptions = {
        user: data.user,
        password: data.pass,
        host: host,
        port: port,
        database: data.db_name
    };
    if (create_connections > 0) {
        this._createConnections(connectionOptions, create_connections);
    } else if (create_connections < 0) {
        /*
         * zamieniam liczbe ujemna na dodatnia, np.:
         * -5 = 5;
         * oznacza ze usuwamy 5 połaczeń
         */
        create_connections = -create_connections;
        this._removeConnections(create_connections);
    }
    this._executeQueuedQueries();
};

/**
 * Usuwanie nadmiarowych polaczen
 *
 * @param {Number} n  ilosc nadmiarowych polaczeń
 */
MySQLCredentialPool.prototype._removeConnections = function (n) {
    var that = this;

    for (var i = 0; i < n; i++) {
        if (this.getKnownLength() == 0) {
            break;
        }
        this.get(function (client) {
            that.markForDeletion(client);
            that.release(client);
        });
    }
};

/**
 * Tworzenie brakujacych polaczen
 *
 * @param {Object} connectionOptions - opcje dla polaczenia MySQL (host, port)
 * @param {Number} n - ilosc połączeń do utworzenia
 */
MySQLCredentialPool.prototype._createConnections = function (connectionOptions, n) {
    var toCount = n;
    var that = this;
    var isError = false;

    var onConnection = function (err) {
        if (err) {
            isError = true;
        }

        /* semafór */
        if (--toCount) return;
        /* *** */

        if (isError) {
            that._scheduleRenewCredential();
        }
    };

    for (var i = 0; i < n; i++) {
        this._createConnection(connectionOptions, onConnection);
    };
};

/**
 * Towrzenie pojedynczego połączenia do MySQL
 *
 * @param {Object} connectionOptions - opcje dla polaczenia MySQL (host, port)
 * @param {Function} callback - callback po zakonczeniu tworzenia połaczenia
 */
MySQLCredentialPool.prototype._createConnection = function (connectionOptions, callback) {
    var that = this;
    var client = mysql.createConnection(connectionOptions);

    var onConnectionError = function (error) {
        client.destroy();
        callback(error);
    };

    /* timeout connectu do MySQL */
    var connectTimeout = setTimeout(function () {
        console.warn('MySQLCredentialPool>MySQL connection timeout');
        that._removeClient(client);
        onConnectionError(new Error('MySQL Connection error'));
    }, 500);

    client.connect(function (err) {
        /* czyszcze timeout - udalo sie zakonczyc faze polączenia */
        clearTimeout(connectTimeout);
        if (err) {
            console.warn('MySQLCredentialPool>MySQL connection error:', err);
            onConnectionError(err);
        } else {
            console.warn('MySQLCredentialPool>MySQL connection established');
            callback(null);
        }
    });

    client.on('close', function (err) {
        console.warn('MySQLCredentialPool>MySQL Close:', err);
        that._removeClient(client);
    });

    client.on('error', function (err) {
        console.warn('MySQLCredentialPool>MySQL Error', err);
    });
    client.query("SET NAMES utf8");
    this.add(client);
};

/**
 * Usuwanie klienta MySQL z puli.
 * Triggeruje odświeżenie credentiali.
 *
 * @param {MySQLClient} client - klient mysqla
 */
MySQLCredentialPool.prototype._removeClient = function (client) {
    this.markForDeletion(client);
    this.release(client);
    this._scheduleRenewCredential();
};

MySQLCredentialPool.prototype._scheduleRenewCredential = function () {
    /* jesli timer jest juz ustawiony to wychodze */
    if (this._credentialTimer) return;

    var that = this;
    this._credentialTimer = setTimeout(function () {
        that._credentialTimer = null;
        that._cm.renewCredential(that._credential);
    }, 2500);
};

MySQLCredentialPool.prototype.destroy = function () {
    this._cm.removeAllEventListeners(CredentialsManager.Event.LOADED);
    this._cm.removeAllEventListeners(CredentialsManager.Event.ERROR);
};

exports.MySQLCredentialPool = MySQLCredentialPool;