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

_examples/pubsubs/sql/main.go

@@ -0,0 +1,95 @@
+// Sources for https://watermill.io/learn/getting-started/
+package main
+
+import (
+	"context"
+	stdSQL "database/sql"
+	"log"
+	"time"
+
+	driver "github.com/go-sql-driver/mysql"
+
+	"github.com/ThreeDotsLabs/watermill"
+	"github.com/ThreeDotsLabs/watermill-sql/v4/pkg/sql"
+	"github.com/ThreeDotsLabs/watermill/message"
+)
+
+func main() {
+	db := createDB()
+	logger := watermill.NewStdLogger(false, false)
+
+	subscriber, err := sql.NewSubscriber(
+		sql.BeginnerFromStdSQL(db),
+		sql.SubscriberConfig{
+			SchemaAdapter:    sql.DefaultMySQLSchema{},
+			OffsetsAdapter:   sql.DefaultMySQLOffsetsAdapter{},
+			InitializeSchema: true,
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	messages, err := subscriber.Subscribe(context.Background(), "example_topic")
+	if err != nil {
+		panic(err)
+	}
+
+	go process(messages)
+
+	publisher, err := sql.NewPublisher(
+		sql.BeginnerFromStdSQL(db),
+		sql.PublisherConfig{
+			SchemaAdapter: sql.DefaultMySQLSchema{},
+		},
+		logger,
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	publishMessages(publisher)
+}
+
+func createDB() *stdSQL.DB {
+	conf := driver.NewConfig()
+	conf.Net = "tcp"
+	conf.User = "root"
+	conf.Addr = "mysql"
+	conf.DBName = "watermill"
+
+	db, err := stdSQL.Open("mysql", conf.FormatDSN())
+	if err != nil {
+		panic(err)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}
+
+func publishMessages(publisher message.Publisher) {
+	for {
+		msg := message.NewMessage(watermill.NewUUID(), []byte(`{"message": "Hello, world!"}`))
+
+		if err := publisher.Publish("example_topic", 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()
+	}
+}