an enum for consumer return value

consume.go

@@ -7,6 +7,20 @@ import (
 	"github.com/streadway/amqp"
 )
 
+// Action is an action that occurs after processed this delivery
+type Action int
+
+type Handler func(d Delivery) (action Action)
+
+const (
+	// Ack default ack this msg after you have successfully processed this delivery.
+	Ack Action = iota
+	// NackDiscard the message will be dropped or delivered to a server configured dead-letter queue.
+	NackDiscard
+	// NackRequeue deliver this message to a different consumer.
+	NackRequeue
+)
+
 // Consumer allows you to create and connect to queues for data consumption.
 type Consumer struct {
 	chManager *channelManager
@@ -69,7 +83,7 @@ func WithConsumerOptionsLogger(log Logger) func(options *ConsumerOptions) {
 // The provided handler is called once for each message. If the provided queue doesn't exist, it
 // will be created on the cluster
 func (consumer Consumer) StartConsuming(
-	handler func(d Delivery) bool,
+	handler Handler,
 	queue string,
 	routingKeys []string,
 	optionFuncs ...func(*ConsumeOptions),
@@ -136,7 +150,7 @@ func (consumer Consumer) StopConsuming(consumerName string, noWait bool) {
 // startGoroutinesWithRetries attempts to start consuming on a channel
 // with an exponential backoff
 func (consumer Consumer) startGoroutinesWithRetries(
-	handler func(d Delivery) bool,
+	handler Handler,
 	queue string,
 	routingKeys []string,
 	consumeOptions ConsumeOptions,
@@ -164,7 +178,7 @@ func (consumer Consumer) startGoroutinesWithRetries(
 // binds the queue to the routing key(s), and starts the goroutines
 // that will consume from the queue
 func (consumer Consumer) startGoroutines(
-	handler func(d Delivery) bool,
+	handler Handler,
 	queue string,
 	routingKeys []string,
 	consumeOptions ConsumeOptions,
@@ -246,12 +260,18 @@ func (consumer Consumer) startGoroutines(
 					handler(Delivery{msg})
 					continue
 				}
-				if handler(Delivery{msg}) {
+				switch handler(Delivery{msg}) {
+				case Ack:
 					err := msg.Ack(false)
 					if err != nil {
 						consumer.logger.Printf("can't ack message: %v", err)
 					}
-				} else {
+				case NackDiscard:
+					err := msg.Nack(false, false)
+					if err != nil {
+						consumer.logger.Printf("can't nack message: %v", err)
+					}
+				case NackRequeue:
 					err := msg.Nack(false, true)
 					if err != nil {
 						consumer.logger.Printf("can't nack message: %v", err)

examples/consumer/main.go

@@ -16,10 +16,9 @@ func main() {
 		log.Fatal(err)
 	}
 	err = consumer.StartConsuming(
-		func(d rabbitmq.Delivery) bool {
+		func(d rabbitmq.Delivery) (action rabbitmq.Action) {
 			log.Printf("consumed: %v", string(d.Body))
-			// true to ACK, false to NACK
-			return true
+			return
 		},
 		"my_queue",
 		[]string{"routing_key", "routing_key_2"},