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node-task/node_modules/mysql/lib/PoolCluster.js

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2014-09-18 15:35:58 -04:00
var Pool = require('./Pool');
var PoolConfig = require('./PoolConfig');
var Util = require('util');
var EventEmitter = require('events').EventEmitter;
module.exports = PoolCluster;
/**
* PoolCluster
*/
function PoolCluster(config) {
EventEmitter.call(this);
config = config || {};
this._canRetry = typeof config.canRetry === 'undefined' ? true : config.canRetry;
this._removeNodeErrorCount = config.removeNodeErrorCount || 5;
this._defaultSelector = config.defaultSelector || 'RR';
this._closed = false;
this._lastId = 0;
this._nodes = {};
this._serviceableNodeIds = [];
this._namespaces = {};
this._findCaches = {};
}
Util.inherits(PoolCluster, EventEmitter);
PoolCluster.prototype.of = function(pattern, selector) {
pattern = pattern || '*';
selector = selector || this._defaultSelector;
selector = selector.toUpperCase();
if (typeof Selector[selector] === 'undefined') {
selector = this._defaultSelector;
}
var key = pattern + selector;
if (typeof this._namespaces[key] === 'undefined') {
this._namespaces[key] = new PoolNamespace(this, pattern, selector);
}
return this._namespaces[key];
};
PoolCluster.prototype.add = function(id, config) {
if (typeof id === 'object') {
config = id;
id = 'CLUSTER::' + (++this._lastId);
}
if (typeof this._nodes[id] === 'undefined') {
this._nodes[id] = {
id: id,
errorCount: 0,
pool: new Pool({config: new PoolConfig(config)})
};
this._serviceableNodeIds.push(id);
this._clearFindCaches();
}
};
PoolCluster.prototype.getConnection = function(pattern, selector, cb) {
var namespace;
if (typeof pattern === 'function') {
cb = pattern;
namespace = this.of();
} else {
if (typeof selector === 'function') {
cb = selector;
selector = this._defaultSelector;
}
namespace = this.of(pattern, selector);
}
namespace.getConnection(cb);
};
PoolCluster.prototype.end = function() {
if (this._closed) {
return;
}
this._closed = true;
for (var id in this._nodes) {
this._nodes[id].pool.end();
}
};
PoolCluster.prototype._findNodeIds = function(pattern) {
if (typeof this._findCaches[pattern] !== 'undefined') {
return this._findCaches[pattern];
}
var foundNodeIds;
if (pattern === '*') { // all
foundNodeIds = this._serviceableNodeIds;
} else if (this._serviceableNodeIds.indexOf(pattern) != -1) { // one
foundNodeIds = [pattern];
} else if (pattern[pattern.length - 1] === '*') {
// wild matching
var keyword = pattern.substring(pattern.length - 1, 0);
foundNodeIds = this._serviceableNodeIds.filter(function (id) {
return id.indexOf(keyword) === 0;
});
} else {
foundNodeIds = [];
}
this._findCaches[pattern] = foundNodeIds;
return foundNodeIds;
};
PoolCluster.prototype._getNode = function(id) {
return this._nodes[id] || null;
};
PoolCluster.prototype._increaseErrorCount = function(node) {
if (++node.errorCount >= this._removeNodeErrorCount) {
var index = this._serviceableNodeIds.indexOf(node.id);
if (index !== -1) {
this._serviceableNodeIds.splice(index, 1);
delete this._nodes[node.id];
this._clearFindCaches();
node.pool.end();
this.emit('remove', node.id);
}
}
};
PoolCluster.prototype._decreaseErrorCount = function(node) {
if (node.errorCount > 0) {
--node.errorCount;
}
};
PoolCluster.prototype._getConnection = function(node, cb) {
var self = this;
node.pool.getConnection(function (err, connection) {
if (err) {
self._increaseErrorCount(node);
cb(err);
return;
} else {
self._decreaseErrorCount(node);
}
connection._clusterId = node.id;
cb(null, connection);
});
};
PoolCluster.prototype._clearFindCaches = function() {
this._findCaches = {};
};
/**
* PoolNamespace
*/
function PoolNamespace(cluster, pattern, selector) {
this._cluster = cluster;
this._pattern = pattern;
this._selector = new Selector[selector]();
}
PoolNamespace.prototype.getConnection = function(cb) {
var clusterNode = this._getClusterNode();
var cluster = this._cluster;
var namespace = this;
if (clusterNode === null) {
var err = new Error('Pool does not exist.')
err.code = 'POOL_NOEXIST';
return cb(err);
}
cluster._getConnection(clusterNode, function(err, connection) {
var retry = err && cluster._canRetry
&& cluster._findNodeIds(namespace._pattern).length !== 0;
if (retry) {
return namespace.getConnection(cb);
}
if (err) {
return cb(err);
}
cb(null, connection);
});
};
PoolNamespace.prototype._getClusterNode = function _getClusterNode() {
var foundNodeIds = this._cluster._findNodeIds(this._pattern);
var nodeId;
switch (foundNodeIds.length) {
case 0:
nodeId = null;
break;
case 1:
nodeId = foundNodeIds[0];
break;
default:
nodeId = this._selector(foundNodeIds);
break;
}
return nodeId !== null
? this._cluster._getNode(nodeId)
: null;
};
/**
* Selector
*/
var Selector = {};
Selector.RR = function () {
var index = 0;
return function(clusterIds) {
if (index >= clusterIds.length) {
index = 0;
}
var clusterId = clusterIds[index++];
return clusterId;
};
};
Selector.RANDOM = function () {
return function(clusterIds) {
return clusterIds[Math.floor(Math.random() * clusterIds.length)];
};
};
Selector.ORDER = function () {
return function(clusterIds) {
return clusterIds[0];
};
};