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

_examples/real-world-examples/receiving-webhooks/main.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	stdHttp "net/http"
+	_ "net/http/pprof"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-http/pkg/http"
+	"github.com/ThreeDotsLabs/watermill-kafka/v3/pkg/kafka"
+	"github.com/ThreeDotsLabs/watermill/message"
+	"github.com/ThreeDotsLabs/watermill/message/router/middleware"
+	"github.com/ThreeDotsLabs/watermill/message/router/plugin"
+)
+
+var (
+	kafkaAddr = flag.String("kafka", "localhost:9092", "The address of the kafka broker")
+	httpAddr  = flag.String("http", ":8080", "The address for the http subscriber")
+)
+
+type Webhook struct {
+	ObjectKind string `json:"object_kind"`
+}
+
+func main() {
+	flag.Parse()
+	logger := watermill.NewStdLogger(true, true)
+
+	kafkaPublisher, err := kafka.NewPublisher(
+		kafka.PublisherConfig{
+			Brokers:   []string{*kafkaAddr},
+			Marshaler: kafka.DefaultMarshaler{},
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	httpSubscriber, err := http.NewSubscriber(
+		*httpAddr,
+		http.SubscriberConfig{
+			UnmarshalMessageFunc: func(topic string, request *stdHttp.Request) (*message.Message, error) {
+				b, err := io.ReadAll(request.Body)
+				if err != nil {
+					return nil, fmt.Errorf("cannot read body: %w", err)
+				}
+
+				return message.NewMessage(watermill.NewUUID(), b), nil
+			},
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	r, err := message.NewRouter(
+		message.RouterConfig{},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	r.AddMiddleware(
+		middleware.Recoverer,
+		middleware.CorrelationID,
+	)
+	r.AddPlugin(plugin.SignalsHandler)
+
+	r.AddHandler(
+		"http_to_kafka",
+		"/webhooks", // this is the URL of our API
+		httpSubscriber,
+		"webhooks", // this is the topic the message will be published to
+		kafkaPublisher,
+		func(msg *message.Message) ([]*message.Message, error) {
+			webhook := Webhook{}
+
+			if err := json.Unmarshal(msg.Payload, &webhook); err != nil {
+				return nil, fmt.Errorf("cannot unmarshal message: %w", err)
+			}
+
+			// Add simple validation
+			if webhook.ObjectKind == "" {
+				return nil, errors.New("empty object kind")
+			}
+
+			// Simply forward the message from HTTP Subscriber to Kafka Publisher
+			return []*message.Message{msg}, nil
+		},
+	)
+
+	go func() {
+		// HTTP server needs to be started after the router is ready.
+		<-r.Running()
+		_ = httpSubscriber.StartHTTPServer()
+	}()
+
+	_ = r.Run(context.Background())
+}