Kestrel client module for NodeJS
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'use strict';
var ee2 = require('eventemitter2').EventEmitter2;
var net = require('net');
var util = require('util');
var types = require('./connectionType.js');
var kestrel = function( options ){
this._settings = {
servers: ['127.0.0.1:22133'],
connectionType: types.ROUND_ROBIN,
reconnect: false,
reconnectDelay: 200
};
this._currentConnection = 0;
this._connections = [];
this._openConnection = null;
if( options instanceof Object ){
for( var key in options ){
if( this._settings[key] !== undefined ){
this._settings[key] = options[key];
}
}
}
this._pendingSetCallback = null;
ee2.call(this);
};
util.inherits(kestrel,ee2);
//open connections to kestrel server(s)
kestrel.prototype.connect = function(){
var type = this._settings.connectionType;
if( types[type] === undefined || types[type] === null ){
throw 'Kestrel Client Connection: Argument 1 Must Be A Valid Kestrel Connection Type';
}
var parts,port,host;
switch( type ){
case types.RANDOM:
case types.ROUND_ROBIN:
for(var i in this._settings.servers){
parts = this._settings.servers[i].split(':');
port = (parts.length>1)?parts[1]:'22133';
host = parts[0];
this._connections.push( _createConnection(port,host,this) );
}
break;
case types.FAILOVER:
var rand = Math.floor( Math.random()*this._settings.servers.length );
parts = this._settings.servers[rand].split(':');
port = (parts.length>1)?parts[1]:'22133';
host = parts[0];
this._connections.push( _createConnection(port,host,this) );
break;
default:
throw 'Kestrel Client Connection: Unknown Connection Type';
}
};
function _createConnection(port, host, self){
var connection = net.connect(port,host);
connection.on('error', function(err){
self._openConnection = null;
self.emit('error', err);
if(self._settings.reconnect){
setTimeout(function(){
self.connect();
},self._settings.reconnectDelay);
}
});
connection.on('data', function(data){
_handleData(data,self);
self.emit('data', data);
});
return connection;
}
function _handleData(data, self){
data = data.toString();
if( data.match('STORED\r\n') ){
self.emit('stored', true);
if(self._pendingSetCallback){
var callback = self._pendingSetCallback;
self._pendingSetCallback = null;
callback(null);
}
}
if( data.match(/^VALUE/) ){
_handleGet(data,self);
}
if( data.match(/^STAT/) ){
_handleStats(data,self);
}
if( data.match(/^queue/) ){
_handleDumpStats(data, self);
}
if( data == 'DELETED\r\n' ){
self.emit('deleted', true);
}
if( data.match(/^VERSION/) ){
self.emit('version', data.split(' ')[1].replace('\r\n',''));
}
if( data == 'Reloaded config.\r\n' ){
self.emit('reloaded', true);
}
if( data == 'END\r\n' ){
self.emit('empty', null);
}
}
function _handleGet(data, self){
var msg = {};
var parts = data.split('\r\n');
msg.queue = parts[0].match(/([a-zA-Z_]+)/mg)[1];
msg.data = parts[1].replace('\r\n','');
self.emit('message', msg);
}
function _handleStats(data, self){
var stats = {};
var parts = data.match(/STAT ([a-zA-Z_]+) (.*?)\r\n/g);
for( var i in parts ){
var part = parts[i].split(' ');
stats[part[1]] = part[2].replace('\r\n', '');
}
self.emit('stats', stats);
}
function _handleDumpStats(data, self){
var stats = {};
var parts = data.replace('\r\n}\r\nEND','').split('}\r\n');
for( var i in parts ){
var part = parts[i].split('\r\n');
var queue = part[0].match(/[a-zA-Z_]+/g)[1];
stats[queue] = {};
for( var lcv = 1; lcv < part.length-1; ++lcv ){
var p = part[lcv].split('=');
stats[queue][ p[0].replace(/ /g,'') ] = p[1];
}
}
self.emit('dump_stats', stats);
}
kestrel.prototype._getConnection = function(){
if( this._connections.length == 1 ) {
return this._connections[0];
} else if( this._connections.length === 0 ) {
return null;
}
var connection = null;
switch(this._settings.connectionType) {
case types.RANDOM:
var rand = Math.floor( Math.random()*this._connections.length );
connection = this._connections[rand];
break;
case types.ROUND_ROBIN:
this._currentConnection += 1;
if( this._currentConnection > this._connections.length ){
this._currentConnection = 0;
}
connection = this._connections[this._currentConnection];
break;
case types.FAILOVER:
connection = this._connections[0];
break;
}
return connection;
};
kestrel.prototype.close = function(){
//close any open connections
for( var i in this._connections ){
this._connections[i].destroy();
}
};
kestrel.prototype.set = function( queue, value, lifetime, callback){
if( typeof(lifetime) === 'function' ){
callback = lifetime;
lifetime = null;
}
if( lifetime === undefined || lifetime === null ){
lifetime = 0;
}
if(this._pendingSetCallback && callback){
return callback('Cannot write again. Still waiting for previous write to be stored');
}
var command = 'SET ' + queue + ' 0 ' + lifetime + ' ';
command += Buffer.byteLength(value, 'utf8') + '\r\n';
var connection = this._getConnection();
if( connection ){
if(callback){
this._pendingSetCallback = callback;
}
connection.write(command);
connection.write(value);
connection.write('\r\n');
} else {
if(callback){
callback('No connection');
} else {
throw new Error('No connection');
}
}
return this;
};
kestrel.prototype.get = function(queue, timeout){
var command = 'GET ' + queue;
timeout = parseInt(timeout,10);
if( timeout > 0 ){
command += '/t='+timeout;
}
var connection = this._getConnection();
if( connection ){
connection.write(command + '\r\n');
}
return this;
};
kestrel.prototype.getNextOpen = function(queue, timeout){
var command = 'GET ' + queue;
timeout = parseInt(timeout,10);
if( timeout > 0 ){
command += '/t='+timeout;
}
var connection = this._openConnection;
if(connection) {
command += '/close';
} else {
connection = this._getConnection();
this._openConnection = connection;
}
command += '/open';
if( connection ){
connection.write(command + '\r\n');
}
return this;
};
kestrel.prototype.delete = function(queue){
//delete given queue
var connection = this._getConnection();
if( connection ){
connection.write('DELETE ' + queue + '\r\n');
}
return this;
};
kestrel.prototype.flush = function(queue){
//flush given queue
var connection = this._getConnection();
if( connection ){
connection.write('FLUSH ' + queue + '\r\n');
}
return this;
};
kestrel.prototype.flushAll = function(){
//flush all queues
var connection = this._getConnection();
if( connection ){
connection.write('FLUSH_ALL\r\n');
}
return this;
};
kestrel.prototype.version = function(){
//get version of server
var connection = this._getConnection();
if( connection ){
connection.write('VERSION\r\n');
}
return this;
};
kestrel.prototype.shutdown = function(){
//shutdown server
var connection = this._getConnection();
if( connection ){
connection.write('SHUTDOWN\r\n');
}
return this;
};
kestrel.prototype.reload = function(){
//reload the server
var connection = this._getConnection();
if( connection ){
connection.write('RELOAD\r\n');
}
return this;
};
kestrel.prototype.stats = function(){
//get server stats
var connection = this._getConnection();
if( connection ){
connection.write('STATS\r\n');
}
return this;
};
kestrel.prototype.dumpStats = function(){
//dump server stats
var connection = this._getConnection();
if( connection ){
connection.write('DUMP_STATS\r\n');
}
return this;
};
kestrel.prototype.monitor = function(queue, seconds, maxItems){
//monitor the given queue
};
kestrel.prototype.confirm = function(queue, count){
//confirm received items
};
module.exports = kestrel;