snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

_examples/pubsubs/nats-core/main.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-nats/v2/pkg/nats"
+	"github.com/ThreeDotsLabs/watermill/message"
+	nc "github.com/nats-io/nats.go"
+)
+
+func main() {
+	natsURL := "nats://nats:4222"
+	marshaler := &nats.GobMarshaler{}
+	logger := watermill.NewStdLogger(false, false)
+	options := []nc.Option{
+		nc.RetryOnFailedConnect(true),
+		nc.Timeout(30 * time.Second),
+		nc.ReconnectWait(1 * time.Second),
+	}
+
+	jsConfig := nats.JetStreamConfig{Disabled: true}
+
+	subscriber, err := nats.NewSubscriber(
+		nats.SubscriberConfig{
+			URL:            natsURL,
+			CloseTimeout:   30 * time.Second,
+			AckWaitTimeout: 30 * time.Second,
+			NatsOptions:    options,
+			Unmarshaler:    marshaler,
+			JetStream:      jsConfig,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	c := make(chan os.Signal)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		<-c
+		fmt.Println("\r- Ctrl+C pressed in Terminal - closing subscriber")
+		subscriber.Close()
+		os.Exit(0)
+	}()
+
+	messages, err := subscriber.Subscribe(context.Background(), "example_topic_nats")
+	if err != nil {
+		panic(err)
+	}
+
+	go process(messages)
+
+	publisher, err := nats.NewPublisher(
+		nats.PublisherConfig{
+			URL:         natsURL,
+			NatsOptions: options,
+			Marshaler:   marshaler,
+			JetStream:   jsConfig,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	publishMessages(publisher)
+}
+
+func publishMessages(publisher message.Publisher) {
+	for {
+		msg := message.NewMessage(watermill.NewUUID(), []byte("Hello, world!"))
+
+		if err := publisher.Publish("example_topic_nats", msg); err != nil {
+			panic(err)
+		}
+
+		time.Sleep(time.Second)
+	}
+}
+
+func process(messages <-chan *message.Message) {
+	for msg := range messages {
+		log.Printf("received message: %s, payload: %s", msg.UUID, string(msg.Payload))
+
+		// we need to Acknowledge that we received and processed the message,
+		// otherwise, it will be resent over and over again.
+		msg.Ack()
+	}
+}