This tutorial assumes RabbitMQ is installed and running on localhost on standard port (5672). In case you use a different host, port or credentials, connections settings would require adjusting.

Where to get help

If you're having trouble going through this tutorial you can contact us through the mailing list.

RabbitMQ is a message broker. The principal idea is pretty simple: it accepts and forwards messages. You can think about it as a post office: when you send mail to the post box you're pretty sure that Mr. Postman will eventually deliver the mail to your recipient. Using this metaphor RabbitMQ is a post box, a post office and a postman.

The major difference between RabbitMQ and the post office is the fact that it doesn't deal with paper, instead it accepts, stores and forwards binary blobs of data ‒ messages.

RabbitMQ, and messaging in general, uses some jargon.

  • Producing means nothing more than sending. A program that sends messages is a producer. We'll draw it like that, with "P":

    digraph { bgcolor=transparent; truecolor=true; rankdir=LR; node [style="filled"]; // P1 [label="P", fillcolor="#00ffff"]; }

  • A queue is the name for a mailbox. It lives inside RabbitMQ. Although messages flow through RabbitMQ and your applications, they can be stored only inside a queue. A queue is not bound by any limits, it can store as many messages as you like ‒ it's essentially an infinite buffer. Many producers can send messages that go to one queue, many consumers can try to receive data from one queue. A queue will be drawn as like that, with its name above it:

    digraph { bgcolor=transparent; truecolor=true; rankdir=LR; node [style="filled"]; // subgraph cluster_Q1 { label="queue_name"; color=transparent; Q1 [label="{||||}", fillcolor="red", shape="record"]; }; }

  • Consuming has a similar meaning to receiving. A consumer is a program that mostly waits to receive messages. On our drawings it's shown with "C":

    digraph { bgcolor=transparent; truecolor=true; rankdir=LR; node [style="filled"]; // C1 [label="C", fillcolor="#33ccff"]; }

Note that the producer, consumer, and broker do not have to reside on the same machine; indeed in most applications they don't.

"Hello World"

(using the php-amqplib Client)

In this part of the tutorial we'll write two programs in PHP; a producer that sends a single message, and a consumer that receives messages and prints them out. We'll gloss over some of the detail in the php-amqplib API, concentrating on this very simple thing just to get started. It's a "Hello World" of messaging.

In the diagram below, "P" is our producer and "C" is our consumer. The box in the middle is a queue - a message buffer that RabbitMQ keeps on behalf of the consumer.

(P) -> [|||] -> (C)

The php-amqplib client library

RabbitMQ speaks multiple protocols. This tutorial covers AMQP 0-9-1, which is an open, general-purpose protocol for messaging. There are a number of clients for RabbitMQ in many different languages. We'll use the php-amqplib in this tutorial, and Composer for dependency management.

Add a composer.json file to your project:

    "require": {
        "php-amqplib/php-amqplib": "2.5.*"

Provided you have Composer installed and functional, you can run the following:

$ composer.phar install

There's also a Composer installer for Windows.

Now we have the php-amqplib library installed, we can write some code.


(P) -> [|||]

We'll call our message sender send.php and our message receiver receive.php. The sender will connect to RabbitMQ, send a single message, then exit.

In send.php, we need to include the library and use the necessary classes:

require_once __DIR__ . '/vendor/autoload.php';
use PhpAmqpLib\Connection\AMQPStreamConnection;
use PhpAmqpLib\Message\AMQPMessage;

then we can create a connection to the server:

$connection = new AMQPStreamConnection('localhost', 5672, 'guest', 'guest');
$channel = $connection->channel();

The connection abstracts the socket connection, and takes care of protocol version negotiation and authentication and so on for us. Here we connect to a broker on the local machine - hence the localhost. If we wanted to connect to a broker on a different machine we'd simply specify its name or IP address here.

Next we create a channel, which is where most of the API for getting things done resides.

To send, we must declare a queue for us to send to; then we can publish a message to the queue:

$channel->queue_declare('hello', false, false, false, false);

$msg = new AMQPMessage('Hello World!');
$channel->basic_publish($msg, '', 'hello');

echo " [x] Sent 'Hello World!'\n";

Declaring a queue is idempotent - it will only be created if it doesn't exist already. The message content is a byte array, so you can encode whatever you like there.

Lastly, we close the channel and the connection;


Here's the whole send.php class.

Sending doesn't work!

If this is your first time using RabbitMQ and you don't see the "Sent" message then you may be left scratching your head wondering what could be wrong. Maybe the broker was started without enough free disk space (by default it needs at least 1Gb free) and is therefore refusing to accept messages. Check the broker logfile to confirm and reduce the limit if necessary. The configuration file documentation will show you how to set disk_free_limit.


That's it for our sender. Our receiver is pushed messages from RabbitMQ, so unlike the sender which publishes a single message, we'll keep it running to listen for messages and print them out.

[|||] -> (C)

The code (in receive.php) has almost the same include and uses as send:

require_once __DIR__ . '/vendor/autoload.php';
use PhpAmqpLib\Connection\AMQPStreamConnection;

Setting up is the same as the sender; we open a connection and a channel, and declare the queue from which we're going to consume. Note this matches up with the queue that send publishes to.

$connection = new AMQPStreamConnection('localhost', 5672, 'guest', 'guest');
$channel = $connection->channel();

$channel->queue_declare('hello', false, false, false, false);

echo ' [*] Waiting for messages. To exit press CTRL+C', "\n";

Note that we declare the queue here, as well. Because we might start the receiver before the sender, we want to make sure the queue exists before we try to consume messages from it.

We're about to tell the server to deliver us the messages from the queue. We will define a PHP callable that will receive the messages sent by the server. Keep in mind that messages are sent asynchronously from the server to the clients.

$callback = function($msg) {
  echo " [x] Received ", $msg->body, "\n";

$channel->basic_consume('hello', '', false, true, false, false, $callback);

while(count($channel->callbacks)) {

Our code will block while our $channel has callbacks. Whenever we receive a message our $callback function will be passed the received message.

Here's the whole receive.php class

Putting it all together

Now we can run both scripts. In a terminal, run the sender:

$ php send.php

then, run the receiver:

$ php receive.php

The receiver will print the message it gets from the sender via RabbitMQ. The receiver will keep running, waiting for messages (Use Ctrl-C to stop it), so try running the sender from another terminal.

If you want to check on the queue, try using rabbitmqctl list_queues.

Hello World!

Time to move on to part 2 and build a simple work queue.