add monitor

monitor.go

@@ -0,0 +1,72 @@
+package delayqueue
+
+import (
+	"log"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// Monitor can get running status and events of DelayQueue
+type Monitor struct {
+	inner *DelayQueue
+}
+
+// NewMonitor0 creates a new Monitor by a RedisCli instance
+func NewMonitor0(name string, cli RedisCli, opts ...interface{}) *Monitor {
+	opts = append(opts, noCallbackOpt(1))
+	return &Monitor{
+		inner: NewQueue0(name, cli, nil, opts...),
+	}
+}
+
+// NewPublisher creates a new Publisher by a *redis.Client
+func NewMonitor(name string, cli *redis.Client, opts ...interface{}) *Monitor {
+	rc := &redisV9Wrapper{
+		inner: cli,
+	}
+	return NewMonitor0(name, rc, opts...)
+}
+
+// WithLogger customizes logger for queue
+func (m *Monitor) WithLogger(logger *log.Logger) *Monitor {
+	m.inner.logger = logger
+	return m
+}
+
+// GetPendingCount returns the number of messages which delivery time has not arrived
+func (m *Monitor) GetPendingCount() (int64, error) {
+	return m.inner.GetPendingCount()
+}
+
+// GetReadyCount returns the number of messages which have arrived delivery time but but have not been delivered yet
+func (m *Monitor) GetReadyCount() (int64, error) {
+	return m.inner.GetReadyCount()
+}
+
+// GetProcessingCount returns the number of messages which are being processed
+func (m *Monitor) GetProcessingCount() (int64, error) {
+	return m.inner.GetProcessingCount()
+}
+
+// ListenEvent register a listener which will be called when events occured in this queue
+// so it can be used to monitor running status
+// returns: close function, error
+func (m *Monitor) ListenEvent(listener EventListener) (func(), error) {
+	reportChan := genReportChannel(m.inner.name)
+	sub, closer, err := m.inner.redisCli.Subscribe(reportChan)
+	if err != nil {
+		return nil, err
+	}
+	go func() {
+		for payload := range sub {
+			event, err := decodeEvent(payload)
+			if err != nil {
+				m.inner.logger.Printf("[listen event] %v\n", event)
+			} else {
+				listener.OnEvent(event)
+			}
+		}
+	}()
+	return closer, nil
+}
+