first commit

batch/pubsub/job-subscriber.js

@@ -0,0 +1,54 @@
+'use strict';
+
+var Channel = require('./channel');
+var debug = require('./../util/debug')('pubsub:subscriber');
+var error = require('./../util/debug')('pubsub:subscriber:error');
+
+function JobSubscriber(pool) {
+    this.pool = pool;
+}
+
+module.exports = JobSubscriber;
+
+JobSubscriber.prototype.subscribe = function (onJobHandler, callback) {
+    var self = this;
+
+    self.pool.acquire(Channel.DB, function(err, client) {
+        if (err) {
+            if (callback) {
+                callback(err);
+            }
+            return error('Error adquiring redis client: ' + err.message);
+        }
+
+        self.client = client;
+        client.removeAllListeners('message');
+        client.unsubscribe(Channel.NAME);
+        client.subscribe(Channel.NAME);
+
+        client.on('message', function (channel, user) {
+            debug('message received in channel=%s from user=%s', channel, user);
+            onJobHandler(user);
+        });
+
+        client.on('error', function () {
+            self.unsubscribe();
+            self.pool.release(Channel.DB, client);
+            self.subscribe(onJobHandler);
+        });
+
+        if (callback) {
+            callback();
+        }
+    });
+};
+
+JobSubscriber.prototype.unsubscribe = function (callback) {
+    if (this.client && this.client.connected) {
+        this.client.unsubscribe(Channel.NAME, callback);
+    } else {
+        if (callback) {
+            return callback(null);
+        }
+    }
+};