From cbe1890a558afeca73e37c927bb33ee459d2d485 Mon Sep 17 00:00:00 2001
From: Giriraj Sharma <giriraj.sharma@paytm.com>
Date: Mon, 14 Sep 2015 17:51:17 +0530
Subject: [PATCH] Provided a tutorial for RabbitMq priority queue
implementation
---
examples/tutorials/README.md | 9 +++++
.../callback_api/receive_priority_queue.js | 30 ++++++++++++++++
.../callback_api/send_priority_queue.js | 36 +++++++++++++++++++
3 files changed, 75 insertions(+)
create mode 100644 examples/tutorials/callback_api/receive_priority_queue.js
create mode 100644 examples/tutorials/callback_api/send_priority_queue.js
diff --git a/examples/tutorials/README.md b/examples/tutorials/README.md
index d234d994..c46784c3 100644
--- a/examples/tutorials/README.md
+++ b/examples/tutorials/README.md
@@ -80,6 +80,14 @@ and routing replies back to clients.
* [rpc_server.js](rpc_server.js)
* [rpc_client.js](rpc_client.js)
+## [Tutorial seven: Priority Queue][tute-seven]
+
+RabbitMQ has priority queue implementation in the core as of version 3.5.0.
+Using RabbitMQ as a priority queue, showing how to set maximum priority value supported by the queue and setting priority of each message pushed to the queue. In case of messages having equal value of priority, they are consumed in FIFO order.
+
+ * [send_priority_queue.js](callback_api/send_priority_queue.js)
+ * [receive_priority_queue.js](callback_api/receive_priority_queue.js)
+
I depart slightly from the original tutorial code, which I think has
some needless object-orientation (in the Python code; you don't get a
choice about needless object-orientation in Java).
@@ -91,3 +99,4 @@ choice about needless object-orientation in Java).
[tute-four]: http://www.rabbitmq.com/tutorials/tutorial-four-python.html
[tute-five]: http://www.rabbitmq.com/tutorials/tutorial-five-python.html
[tute-six]: http://www.rabbitmq.com/tutorials/tutorial-six-python.html
+[tute-seven]: https://www.rabbitmq.com/priority.html
diff --git a/examples/tutorials/callback_api/receive_priority_queue.js b/examples/tutorials/callback_api/receive_priority_queue.js
new file mode 100644
index 00000000..bcb9842f
--- /dev/null
+++ b/examples/tutorials/callback_api/receive_priority_queue.js
@@ -0,0 +1,30 @@
+#!/usr/bin/env node
+
+var amqp = require('amqplib/callback_api');
+
+function bail(err, conn) {
+ console.error(err);
+ if (conn) conn.close(function() { process.exit(1); });
+}
+
+function on_connect(err, conn) {
+ if (err !== null) return bail(err);
+ process.once('SIGINT', function() { conn.close(); });
+
+ var q = 'hello';
+
+ function on_channel_open(err, ch) {
+ ch.assertQueue(q, {durable: false, maxPriority: 10}, function(err, ok) {
+ if (err !== null) return bail(err, conn);
+ ch.consume(q, function(msg) { // message callback
+ console.log(" [x] Received '%s'", msg.content.toString());
+ }, {noAck: true}, function(_consumeOk) { // consume callback
+ console.log(' [*] Waiting for messages. To exit press CTRL+C');
+ });
+ });
+ }
+
+ conn.createChannel(on_channel_open);
+}
+
+amqp.connect(on_connect);
diff --git a/examples/tutorials/callback_api/send_priority_queue.js b/examples/tutorials/callback_api/send_priority_queue.js
new file mode 100644
index 00000000..8db77596
--- /dev/null
+++ b/examples/tutorials/callback_api/send_priority_queue.js
@@ -0,0 +1,36 @@
+#!/usr/bin/env node
+
+var amqp = require('amqplib/callback_api');
+
+function bail(err, conn) {
+ console.error(err);
+ if (conn) conn.close(function() { process.exit(1); });
+}
+
+function on_connect(err, conn) {
+ if (err !== null) return bail(err);
+
+ var q = 'hello';
+ var message = '';
+ var priorityValue = 0;
+
+ function on_channel_open(err, ch) {
+ if (err !== null) return bail(err, conn);
+ ch.assertQueue(q, {durable: false, maxPriority: 10}, function(err, ok) {
+ if (err !== null) return bail(err, conn);
+
+ for(var index=1; index<=50; index++) {
+ priorityValue = Math.floor((Math.random() * 10));
+ // index refers to message number. Lower is the index value, earlier is the message pushed into the queue.
+ message = 'Message index = ' + index + ' and Priority Value = ' + priorityValue;
+ ch.sendToQueue(q, new Buffer(message), {priority: priorityValue});
+ console.log(" [x] Sent '%s'", message);
+ }
+ ch.close(function() { conn.close(); });
+ });
+ }
+
+ conn.createChannel(on_channel_open);
+}
+
+amqp.connect(on_connect);