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node.js
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node.js
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var redis = require('redis')
, util = require('util')
, EventEmitter = require('events').EventEmitter
, dns = require('dns')
, async = require('async')
;
function Node(spec, options) {
var self = this;
this.host = spec.host;
this.port = spec.port;
this.clients = [];
options = options || {};
if (typeof options.no_ready_check == 'undefined') {
options.no_ready_check = true;
}
this.options = {};
Object.keys(options).forEach(function(k) {
self.options[k] = options[k];
});
// Resolve host, to prevent false duplication
Node.resolveHost(this.host, function(err, host) {
if (err) {
return self.emit('error', err);
}
self.host = host;
self.connect();
});
}
util.inherits(Node, EventEmitter);
// Static method
Node.resolveHost = function(host, cb) {
dns.lookup(host, 4, cb);
};
Node.parseInfo = function(reply) {
var lines = reply.toString().split("\r\n"), obj = {};
lines.forEach(function(line) {
var parts = line.split(':');
if (parts[1]) {
obj[parts[0]] = parts[1];
}
});
obj.versions = [];
obj.redis_version.split('.').forEach(function(num) {
obj.versions.push(+num);
});
return obj;
};
Node.prototype.connect = function() {
var self = this;
this.setStatus('initializing');
this.client = redis.createClient(this.port, this.host, this.options);
if (this.auth_pass) {
this.client.auth(this.auth_pass);
}
this.clients.push(this.client);
this.client.on('error', function(err) {
self.emit('error', err);
});
this.client.on('end', function() {
if (!this.closing) {
self.setStatus('down');
}
});
this.client.on('connect', function() {
if (self.options.single_mode) {
// No failover possible, don't check for slave-read-only
self.setStatus('up');
}
else {
self.client.CONFIG('GET', 'slave-read-only', function(err, reply) {
if (err) {
return self.emit('error', err);
}
if (reply[1] !== 'yes') {
self.setStatus('up');
}
else {
console.warn('WARNING! ' + self.toString() + ' has slave-read-only mode ON, which breaks haredis failover! slave-read-only automatically turned OFF.');
self.client.CONFIG('SET', 'slave-read-only', 'no', function(err, reply) {
if (err) {
return self.emit('error', err);
}
self.setStatus('up');
});
}
});
}
});
this.client.on('monitor', function(time, args) {
self.emit('monitor', time, args);
});
// Maintain a separate pub/sub client.
this.subClient = redis.createClient(this.port, this.host, this.options);
if (this.auth_pass) {
this.subClient.auth(this.auth_pass);
}
this.clients.push(this.subClient);
this.subClient.on('error', function(err) {
self.emit('error', err);
});
this.subClient.on('connect', function() {
// UGLY HACK: node_redis does not restore pub/sub subscriptions correctly upon
// reconnect. In fact, the client crashes! Resubscription will be handled at the RedisHAClient level.
// @see https://github.com/mranney/node_redis/issues/191
this.subscribe('haredis:gossip:master');
this.subscription_set = {};
});
// Subtract 1 from all counts, for the gossip channel we've set up.
this.subClient.on('subscribe', function(channel, count) {
self.emit('subscribe', channel, count - 1);
});
this.subClient.on('unsubscribe', function(channel, count) {
self.emit('unsubscribe', channel, count - 1);
});
this.subClient.on('message', function(channel, message) {
self.emit('message', channel, message);
});
this.subClient.on('psubscribe', function(pattern, count) {
self.emit('psubscribe', pattern, count - 1);
});
this.subClient.on('punsubscribe', function(pattern, count) {
self.emit('punsubscribe', pattern, count - 1);
});
this.subClient.on('pmessage', function(pattern, channel, message) {
self.emit('pmessage', pattern, channel, message);
});
};
Node.prototype.incrOpcounter = function(count, done) {
// Master-only operation
if (this.role != 'master' || this.options.single_mode) {
return;
}
if (typeof count == 'function') {
done = count;
count = 1;
}
var self = this;
// For write operations, increment an op counter, to judge freshness of slaves.
if (!this.opcounterClient) {
this.opcounterClient = redis.createClient(this.port, this.host, this.options);
if (this.auth_pass) {
this.opcounterClient.auth(this.auth_pass);
}
this.clients.push(this.opcounterClient);
if (this.options.haredis_db_num) {
// Make redis connect to a special db (upon ready) for the opcounter.
this.opcounterClient.selected_db = this.options.haredis_db_num;
}
this.opcounterClient.on('error', function(err) {
self.emit('error', err);
self.setStatus('down');
});
}
this.opcounterClient.INCRBY('haredis:opcounter', count, done);
};
Node.prototype.quit = function(callback) {
var tasks = [];
this.clients.forEach(function(client) {
tasks.push(function(cb) {
client.quit(cb);
});
});
async.parallel(tasks, function(err, replies) {
if (callback) {
callback(err, replies);
}
});
};
Node.prototype.setStatus = function(status) {
if (status != this.status) {
this.status = status;
this.emit(status);
}
};
Node.prototype.toString = function() {
return this.host + ':' + this.port;
};
module.exports = Node;