Example Golang worker with rabbitMQ graceful shutdown

main.go

package main

import (
	"flag"
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/streadway/amqp"
)

// newConsumer is a function create a rabbitMQ consumer
func newConsumer(connectionString, queueName, consumerName string, fetchCount int) (connection *amqp.Connection, channel *amqp.Channel, msgs <-chan amqp.Delivery) {
	connection, _ = amqp.Dial(connectionString)
	channel, _ = connection.Channel()
	channel.Qos(fetchCount, 0, false)
	msgs, _ = channel.Consume(
		queueName,    // queue
		consumerName, // consumer
		false,        // auto-ack
		false,        // exclusive
		false,        // no-local
		false,        // no-wait
		nil,          // args
	)
	return
}

func worker(msgs <-chan amqp.Delivery, done chan bool) {

	for m := range msgs {
		body := string(m.Body)
		log.Printf("Processing data %+v\n", body)
		time.Sleep(5 * time.Second)
		log.Printf("Processing data %+v done\n", body)
		m.Ack(false)
		log.Printf("Data %+v acked\n", body)
	}
	done <- true
}

func main() {
	defer log.Println("Program stopped successful")
	url := flag.String("url", "", "eg. amqp://root:toor@localhost:5672/")
	queue := flag.String("queue", "", "eg. test-queue")
	name := flag.String("name", "", "eg. consumer-1")
	fetchSize := flag.Int("size", 1, "eg. 20")
	flag.Parse()

	log.Printf("Connecting to %s queue %s fetch-size %d\n", *url, *queue, *fetchSize)

	connection, channel, msgs := newConsumer(*url, *queue, *name, *fetchSize)

	log.Printf("Consumer %s is subscribing queue %s\n", *name, *queue)

	defer connection.Close()
	defer channel.Close()
	defer log.Println("Closing qeueu channel and connection")

	done := make(chan bool)

	go worker(msgs, done)

	exit := make(chan os.Signal, 1)
	signal.Notify(exit, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)

	// Wait for OS exit signal
	<-exit
	log.Println("Got exit signal")
	// Stop recieving message from queue
	channel.Cancel(*name, false)
	log.Println("Stopped receiving message from queue")
	// Wait for worker procrss recieved message
	log.Println("Wait for worker procrss recieved message")
	<-done
	log.Println("Woker done")
}