Mini Project: Order Event Pipeline with Go and RabbitMQ

type OrderCreated struct {
	OrderID    string    `json:"order_id"`
	UserID     string    `json:"user_id"`
	Amount     int64     `json:"amount"`
	OccurredAt time.Time `json:"occurred_at"`
	EventID    string    `json:"event_id"`
}
 
func publishOrderCreated(ch *amqp.Channel, evt OrderCreated) error {
	body, err := json.Marshal(evt)
	if err != nil {
		return err
	}
 
	return ch.Publish("orders.topic", "order.created", false, false, amqp.Publishing{
		ContentType:  "application/json",
		DeliveryMode: amqp.Persistent,
		Body:         body,
		Timestamp:    time.Now(),
		MessageId:    evt.EventID,
	})
}

for msg := range msgs {
	if alreadyProcessed(msg.MessageId) {
		_ = msg.Ack(false)
		continue
	}
 
	if err := handleOrderCreated(msg.Body); err != nil {
		if isTemporary(err) {
			_ = msg.Nack(false, true)
		} else {
			_ = msg.Nack(false, false)
		}
		continue
	}
 
	markProcessed(msg.MessageId)
	_ = msg.Ack(false)
}