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

_examples/real-world-examples/exactly-once-delivery-counter/server/main.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	stdSQL "database/sql"
+	"encoding/json"
+	"log"
+	"net/http"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-sql/v4/pkg/sql"
+	"github.com/ThreeDotsLabs/watermill/message"
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/chi/v5/middleware"
+	driver "github.com/go-sql-driver/mysql"
+)
+
+const topic = "counter"
+
+func main() {
+	db := createDB()
+	logger := watermill.NewStdLogger(false, false)
+
+	r := chi.NewRouter()
+	r.Use(middleware.Recoverer)
+	r.Use(middleware.Logger)
+
+	publisher, err := sql.NewPublisher(
+		sql.BeginnerFromStdSQL(db),
+		sql.PublisherConfig{
+			SchemaAdapter: sql.DefaultMySQLSchema{},
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	r.Post("/count/{counterUUID}", func(w http.ResponseWriter, r *http.Request) {
+		payload, err := json.Marshal(messagePayload{
+			CounterUUID: chi.URLParam(r, "counterUUID"),
+		})
+		if err != nil {
+			log.Print(err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		msg := message.NewMessage(watermill.NewUUID(), payload)
+
+		if err := publisher.Publish(topic, msg); err != nil {
+			log.Print(err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		w.WriteHeader(http.StatusNoContent)
+	})
+
+	err = http.ListenAndServe(":8080", r)
+	if err != nil {
+		panic(err)
+	}
+}
+
+type messagePayload struct {
+	CounterUUID string `json:"counter_uuid"`
+}
+
+func createDB() *stdSQL.DB {
+	conf := driver.NewConfig()
+	conf.Net = "tcp"
+	conf.User = "root"
+	conf.Addr = "mysql"
+	conf.DBName = "example"
+
+	db, err := stdSQL.Open("mysql", conf.FormatDSN())
+	if err != nil {
+		panic(err)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}