NATS Drain Mode

drain.go

package main

import (
	"log"
	"os"
	"os/signal"
	"runtime"
	"syscall"

	"github.com/nats-io/go-nats"
)

func main() {
	// When we get called back that we are closed, go ahead and exit.
	closed := func(nc *nats.Conn) {
		log.Printf("Connection closed, exiting\n")
		os.Exit(0)
	}

	// Connect to NATS
	nc, err := nats.Connect("tls://demo.nats.io:4443", nats.ClosedHandler(closed))
	if err != nil {
		log.Fatalf("Can't connect: %v\n", err)
	}

	// Queue Worker
	nc.QueueSubscribe("foo", "worker_group", func(m *nats.Msg) {
		// Do some work, then send reply.
		nc.Publish(m.Reply, []byte("Your Answer!"))
	})

	// Now handle signal to terminate.
	c := make(chan os.Signal, 1)
	signal.Notify(c, syscall.SIGINT)

	go func() {
		// Wait for signal
		<-c
		log.Printf("Received signal, entering drain mode\n")
		nc.Drain()
	}()

	runtime.Goexit()
}