add monitor

events.go

@@ -0,0 +1,64 @@
+package delayqueue
+
+import (
+	"errors"
+	"strconv"
+	"strings"
+)
+
+const (
+	// NewMessageEvent emmited when send message
+	NewMessageEvent = iota + 1
+	// ReadyEvent emmited when messages has reached delivery time
+	ReadyEvent
+	// DeliveredEvent emmited when messages has been delivered to consumer
+	DeliveredEvent
+	// AckEvent emmited when receive message successfully consumed callback
+	AckEvent
+	// AckEvent emmited when receive message consumption failure callback
+	NackEvent
+	// RetryEvent emmited when message re-delivered to consumer
+	RetryEvent
+	// FinalFailedEvent emmited when message reaches max retry attempts
+	FinalFailedEvent
+)
+
+// Event contains internal event information during the queue operation and can be used to monitor the queue status.
+type Event struct {
+	// Code represents event type, such as NewMessageEvent, ReadyEvent
+	Code int
+	// Timestamp is the event time
+	Timestamp int64
+	// MsgCount represents the number of messages related to the event
+	MsgCount int
+}
+
+func encodeEvent(e *Event) string {
+	return strconv.Itoa(e.Code) +
+		" " + strconv.FormatInt(e.Timestamp, 10) +
+		" " + strconv.Itoa(e.MsgCount)
+}
+
+func decodeEvent(payload string) (*Event, error) {
+	items := strings.Split(payload, " ")
+	if len(items) != 3 {
+		return nil, errors.New("[decode event error! wrong item count, payload: " + payload)
+	}
+	code, err := strconv.Atoi(items[0])
+	if err != nil {
+		return nil, errors.New("decode event error! wrong event code, payload: " + payload)
+	}
+	timestamp, err := strconv.ParseInt(items[1], 10, 64)
+	if err != nil {
+		return nil, errors.New("decode event error! wrong timestamp, payload: " + payload)
+	}
+	count, err := strconv.Atoi(items[2])
+	if err != nil {
+		return nil, errors.New("decode event error! wrong msg count, payload: " + payload)
+	}
+	return &Event{
+		Code:      code,
+		Timestamp: timestamp,
+		MsgCount:  count,
+	}, nil
+}