Practical Real-time Data Processing and Analytics

Topic exchanges

When a message is published to a topic exchange, it is sent to all the queues whose routing key matches all, or a portion of the routing key of the message published—for example, if we publish a message to a topic exchange with a key as green.red, then the message would be published to the queue green queue and red queue. To understand it better, here is the figurative explanation for the same:

The message routing key is "first.green.fast" and with topic exchange it's published onto the "green" queue because the word green occurs in there, the "red.fast" queue because the word fast occurs in there, and the "*.fast" queue because ...