RabbitMQ: Example Consumer

What is a Consumer?

A consumer is a service or component that listens to a RabbitMQ queue for incoming messages. Consumers are used to handle tasks asynchronously and process data as it becomes available.

How Does It Work?

1. Connection: The consumer connects to the RabbitMQ server using credentials and the queue name.

2. Listening: It listens to the specified queue for messages.

3. Processing: Upon receiving a message, it processes the data (e.g., storing it in a database or performing calculations).

4. Acknowledgment: Once the processing is done, the message is acknowledged to RabbitMQ.

How to Create a Consumer?

1. Import the RabbitMQ connection library.

2. Define the queue name and configure the connection.

3. Implement a callback function to handle incoming messages.

4. Start the consumer to listen for messages.

package main

import (
    "log"
    "github.com/streadway/amqp"
)

func main() {
    conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
    if err != nil {
        log.Fatalf("Failed to connect to RabbitMQ: %s", err)
    }
    defer conn.Close()

    ch, err := conn.Channel()
    if err != nil {
        log.Fatalf("Failed to open a channel: %s", err)
    }
    defer ch.Close()

    q, err := ch.QueueDeclare(
        "example_queue",
        false,
        false,
        false,
        false,
        nil,
    )
    if err != nil {
        log.Fatalf("Failed to declare a queue: %s", err)
    }

    msgs, err := ch.Consume(
        q.Name,
        "",
        true,
        false,
        false,
        false,
        nil,
    )
    if err != nil {
        log.Fatalf("Failed to register a consumer: %s", err)
    }

    forever := make(chan bool)

    go func() {
        for d := range msgs {
            log.Printf("Received a message: %s", d.Body)
            // Process the message here
        }
    }()

    log.Printf(" [*] Waiting for messages. To exit press CTRL+C")
    <-forever
}