thywill/core/lib/component/cluster/noCluster.js

A Node.js clustered framework for single page web applications based on asynchronous messaging.

/**
 * @fileOverview
 * NoCluster class definition.
 */

var util = require('util');
var Thywill = require('thywill');

//-----------------------------------------------------------
// Class Definition
//-----------------------------------------------------------

/**
 * @class
 * A Cluster implementation for single process backends or multiple process
 * backends that don't need to be cluster-aware.
 *
 * @see Cluster
 */
function NoCluster() {
  NoCluster.super_.call(this);
}
util.inherits(NoCluster, Thywill.getBaseClass('Cluster'));
var p = NoCluster.prototype;

//-----------------------------------------------------------
// 'Static' parameters
//-----------------------------------------------------------

NoCluster.CONFIG_TEMPLATE = {
  localClusterMemberId: {
    _configInfo: {
      description: 'The cluster member ID for this process.',
      types: 'string',
      required: true
    }
  }
};

//-----------------------------------------------------------
// Methods
//-----------------------------------------------------------

/**
 * @see Cluster#getClusterMemberIds
 */
p.getClusterMemberIds = function () {
  return [this.config.localClusterMemberId];
};

/**
 * @see Cluster#getLocalClusterMemberId
 */
p.getLocalClusterMemberId = function () {
  return this.config.localClusterMemberId;
};

/**
 * @see Cluster#getClusterMemberStatus
 */
p.getClusterMemberStatus = function (clusterMemberId, callback) {
  if (clusterMemberId === this.config.localClusterMemberId) {
    callback(this.NO_ERRORS, this.clusterMemberStatus.UP);
  } else {
    callback(this.NO_ERRORS, this.clusterMemberStatus.UNKNOWN);
  }
};

/**
 * @see Cluster#isDesignatedHandlerFor
 */
p.isDesignatedHandlerFor = function (clusterMemberId, callback) {
  // You're your own handler - not that this will do much good, but it's
  // logically correct for the NoCluster single process case.
  if (clusterMemberId === this.config.localClusterMemberId) {
    callback(this.NO_ERRORS, true);
  } else {
    callback(this.NO_ERRORS, false);
  }
};

/**
 * @see Cluster#sendTo
 */
p.sendTo = function (clusterMemberId, taskName, data) {
  data = data || {};
  if (clusterMemberId === this.config.localClusterMemberId) {
    data.taskName = taskName;
    data.clusterMemberId = this.config.localClusterMemberId;
    this.emit(taskName, data);
  }
};

/**
 * @see Cluster#sendToAll
 */
p.sendToAll = function (taskName, data) {
  this.sendTo(this.config.localClusterMemberId, taskName, data);
};

/**
 * @see Cluster#sendToOthers
 */
p.sendToOthers = function (taskName, data) {
  // There are no others.
};

//-----------------------------------------------------------
// Exports - Class Constructor
//-----------------------------------------------------------

module.exports = NoCluster;