91 lines
1.9 KiB
Go
91 lines
1.9 KiB
Go
// Sources for https://watermill.io/docs/getting-started/
|
|
package main
|
|
|
|
import (
|
|
"context"
|
|
"database/sql"
|
|
"log"
|
|
"time"
|
|
|
|
"github.com/ThreeDotsLabs/watermill"
|
|
"github.com/ThreeDotsLabs/watermill-sqlite/wmsqlitemodernc"
|
|
"github.com/ThreeDotsLabs/watermill/message"
|
|
_ "modernc.org/sqlite"
|
|
)
|
|
|
|
func main() {
|
|
db := createDB()
|
|
defer db.Close()
|
|
logger := watermill.NewStdLogger(false, false)
|
|
|
|
subscriber, err := wmsqlitemodernc.NewSubscriber(
|
|
db,
|
|
wmsqlitemodernc.SubscriberOptions{
|
|
InitializeSchema: true,
|
|
Logger: logger,
|
|
},
|
|
)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
messages, err := subscriber.Subscribe(context.Background(), "example_topic")
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
go process(messages)
|
|
|
|
publisher, err := wmsqlitemodernc.NewPublisher(
|
|
db,
|
|
wmsqlitemodernc.PublisherOptions{
|
|
InitializeSchema: true,
|
|
Logger: logger,
|
|
},
|
|
)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
publishMessages(publisher)
|
|
}
|
|
|
|
func createDB() *sql.DB {
|
|
connectionDSN := ":memory:" // or "db.sqlite3?journal_mode=WAL&busy_timeout=1000&cache=shared"
|
|
db, err := sql.Open("sqlite", connectionDSN)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
// limit the number of concurrent connections to one
|
|
// this is a limitation of `modernc.org/sqlite` driver
|
|
db.SetMaxOpenConns(1)
|
|
|
|
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()
|
|
}
|
|
}
|