C++ Programming on Linux - RabbitMQ Topic Exchange Example in C++

RabbitMQ using Exchange, Routing Key and Queue to publish and consume message.

Following is the Standard RabbitMQ message flow
1) The producer publishes a message to the exchange.
2) The exchange receives the message and is now responsible for the routing of the message.
3) Binding must be set up between the queue and the exchange. In this case, we have bindings to two different queues from the exchange. The exchange routes the message into the queues.
4) The messages stay in the queue until they are handled by a consumer.
5) The consumer handles the message.

RabbitMQ Exchange has 4 types.

Direct exchange
Fanout exchange
Topic exchange
Headers exchange

Topic Exchange
Topic exchanges route messages to one or many queues based on matching between a message routing key and the pattern that was used to bind a queue to an exchange. The topic exchange type is often used to implement various publish/subscribe pattern variations. Topic exchanges are commonly used for the multicast routing of messages.

1) The routing key must be a list of words, delimited by a period (.).
2) The routing patterns may contain an asterisk (“*”) to match a word in a specific position of the routing key
3) A pound symbol (“#”) indicates a match of zero or more words

Example:
A) routing pattern of "agreements.*.*.b.*" only match routing keys where the first word is "agreements" and the fourth word is "b"
B) a routing pattern of "agreements.eu.berlin.#" matches any routing keys beginning with "agreements.eu.berlin"

Code of this video has been uploaded onto GitHub for your reference:
https://github.com/yuanhui360/CPP-Programming-on-Linux/tree/main/YH-110