AMQP (Advanced Message Queuing Protocol) is a standardized messaging protocol that enables systems to communicate with each other via message queues in a reliable, asynchronous, and decoupled manner.
It is often used in message brokers like RabbitMQ to support publish/subscribe and message queuing patterns. AMQP defines how messages are formatted, sent, routed, and received between systems.
b. What does it mean? guest:guest@localhost:5672, what is the first guest, and what is the second guest, and what is localhost:5672 is for?
This is a connection URI used to connect to the RabbitMQ server using AMQP protocol:
- First
guest: This is the username used to log into RabbitMQ. - Second
guest: This is the password for that username. localhost: This means the RabbitMQ server is running on the local machine.5672: This is the default AMQP port used by RabbitMQ to listen for incoming client connections.
On my machine, the queue reached a total of 35 messages.
This happened because I ran the publisher multiple times quickly, sending events faster than the subscriber could consume. Since each run of the publisher sends 5 messages, and I ran it 8 times rapidly, the subscriber received and proceed them and the queue had 5 × (8-1) = 35 messages.
As seen in the screenshot, the queue spike is reduced faster than before, because multiple subscribers are now consuming messages simultaneously.
Instead of a single slow subscriber processing one event per second, three subscribers now pull from the same queue.
This enables parallel event processing, which helps reduce the message backlog more quickly.
For example, one console handled:
- “Budi” and “Dira”
While another processed:
- “Amir”, “Cica”, and “Emir”
This confirms that RabbitMQ supports multiple consumers per queue effectively.
On the Publisher side, we could improve the publisher by adding a delay between sends. On the Subscriber side, we could add log thread IDs or subscriber instance IDs to trace parallelism and to know precisely where was each event received.