CartoDB-SQL-API/batch/pubsub/queue-seeker.js
2016-10-11 19:04:12 +02:00

51 lines
1.3 KiB
JavaScript

'use strict';
function QueueSeeker(pool) {
this.db = 5;
this.channel = 'batch:hosts';
this.redisPrefix = 'batch:queues:';
this.pattern = this.redisPrefix + '*';
this.pool = pool;
}
module.exports = QueueSeeker;
QueueSeeker.prototype.seek = function (onMessage, callback) {
var initialCursor = ['0'];
this.onMessage = onMessage;
this._seek(initialCursor, callback);
};
QueueSeeker.prototype._seek = function (cursor, callback) {
var self = this;
var redisParams = [cursor[0], 'MATCH', self.pattern];
this.pool.acquire(this.db, function(err, client) {
if (err) {
return callback(err);
}
client.scan(redisParams, function(err, currentCursor) {
// checks if iteration has ended
if (currentCursor[0] === '0') {
self.pool.release(self.db, client);
return callback(null);
}
var queues = currentCursor[1];
if (!queues) {
return callback(null);
}
queues.forEach(function (queue) {
var host = queue.substr(self.redisPrefix.length);
self.onMessage(self.channel, host);
});
self._seek(currentCursor, callback);
});
});
};