Beginner Tutorial for RabbitMQ

What’s RabbitMQ?

RabbitMQ is a queuing system which is based on queuing protocol called AMQP and mainly used for queuing jobs that’s initiated from a source which we call it a producer, then RabbitMQ manages these requests by putting them in a queue or several queues according to the configuration.

Then these messages are handled by destination which we call consumer.

The main advantage to RabbitMQ or other queuing systems that the decouple the application to different parts, so more control over scalability.

Also better handling for incoming jobs/tasks which maybe very huge number in small amount of time (ex: 100s per second or maybe more), better handling means that they will be distributed to the right queues, consumed by the right consumers and also guarantee that no tasks are stuck or dropped or maybe consumed 2 times by 2 different consumers, which may lead to errors in your application.

Installing RabbitMQ

RabbitMQ is similar to other software, it can be installed using yum/apt and can be installed in 1 minute.

I assume you’re installing on a new server, instead of apt you can use yum if you have centos/RHEL.

sudo apt update && upgrade
sudo apt install erlang
sudo apt install rabbitmq-server
systemctl enable rabbitmq-server
systemctl start rabbitmq-server
systemctl status rabbitmq-server
rabbitmq-plugins enable rabbitmq_management
  • now the above commands installed Erlang as dependency, then RabbitMQ.
  • enabling RabbitMQ.
  • installing management plugin to use its GUI.

now we’ve installed it.

to login do the below.

localhost:15672
or
<http://IP:15672>

In the first command you will access the admin dashboard by using username and password “guest”

the second one will refuse because only localhost is allowed.

to login remotely we need to enable it in configuration, follow the code below.

cd /etc/rabbitmq/nano rabbitmq.conf
#Add the following line, then save and exit
loopback_users = none
#restart the servicesystemctl rabbitmq-server restart

Then login again and it’ll succeed.

we can now add a user that’s admin, follow the below to create a user and add all privileges to it.

rabbitmqctl add_user admin admin
rabbitmqctl set_user_tags admin administrator
rabbitmqctl set_permissions -p / admin "." "." "."

Now we’re logged in with our super admin

Now Let’s jump to the step of building producer.

Building a Producer

to build a producer, i prefer to use nodeJS due to its simplicity and also because i like JavaScript.

at first create a directory to build our project files in it.

and then follow the below commands to prepare the environment, and for npm commands please use it inside project directory

sudo apt install npm
curl -sL <https://deb.nodesource.com/setup_14.x> | sudo -E bash
sudo apt-get install -y nodejs
npm init -y
npm install amqplib

inside the directory we need to create 2 files, producer.js and consumer.js

The below code is a simple code for both producing and consuming your messages

  • we rely on AMQP library to make connection with rabbitmq
  • as in the code you can find that the main function is AMQP which create a connection with RabbitMQ
  • under this connection we need to create a channel that all messages that are produced will be passed by.
  • And inside this channel we can create one or more queues.
  • Then, we finally send a message to the queue

To run the code

node producer.js

Building the producer

we’ll add another file called consumer.js and you can check the file in my github repo.], and you can find that it’s the same as in producer but the difference is in the last point below.

  • we rely on amqp library to make connection with rabbitmq
  • as in the code you can find that the main function is amqp which create a connection with RabbitMQ
  • under this connection we need to create a channel that all messages that are produced will be passed by.
  • And inside this channel we can create one or more queues.
  • Then, we finally receive a message from the queue.

to run the code

node consumer.js

and you can open 2 terminals and run both for live demo.

and in RabbitMQ console you can find the messages like the below, you can find that i have 10 messages that are ready to be consumed in my queue.

I hope you found this demo helpful to start using and learning RabbitMQ

Thank you for reading!

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