nats simple reader

nats-reader.go

package main

import (
	"github.com/nats-io/nats.go"
	"github.com/nats-io/stan.go"
	"os"
	"time"
)

func main() {
	subscribe("nats-url-1.ru,nats-url-2.ru", "nats-cluster", "topic")

	subscribe("nats-url-1.ru,nats-url-2.ru", "nats-cluster", "topic2")

	time.Sleep(48 * time.Hour)
}

func subscribe(url string, cluster string, subject string) {
	clientId := "aleksei-rytikov-test-" + subject

	ncOpts := []nats.Option{
		nats.Name(clientId),
		nats.MaxReconnects(-1),
		nats.ReconnectBufSize(-1),
		nats.UserInfo("login", "password"),
	}

	nc, err := nats.Connect(url, ncOpts...)
	if err != nil {
		println("nats connect err, url", url, "cluster", cluster, err.Error())
		os.Exit(1)
	}

	sc, err := stan.Connect(cluster, clientId, stan.NatsConn(nc))
	go func() {
		for {
			println("Check status. Url: ", url, ". Cluster: ", cluster, ". Subject: ", subject, ". Status: ", sc.NatsConn().Status())
			time.Sleep(60 * time.Second)
		}
	}()
	if err != nil {
		println("stan connect err, url", url, "cluster", cluster, err.Error())
		os.Exit(1)
	}
	_, err = sc.Subscribe(subject, func(m *stan.Msg) {
		println("Message. Url: ", url, ". Cluster: ", cluster, ". Subject: ", subject, ". Timestamp: ", m.Timestamp, ". Data: ", string(m.Data))
	}, stan.DurableName(clientId))
	if err != nil {
		println("subs err, url", url, "cluster", cluster, err.Error())
		os.Exit(1)
	}
}