Rename poller to scheduler

scheduler.go

@@ -0,0 +1,53 @@
+package asynq
+
+import (
+	"log"
+	"time"
+
+	"github.com/hibiken/asynq/internal/rdb"
+)
+
+type scheduler struct {
+	rdb *rdb.RDB
+
+	// channel to communicate back to the long running "scheduler" goroutine.
+	done chan struct{}
+
+	// poll interval on average
+	avgInterval time.Duration
+}
+
+func newScheduler(r *rdb.RDB, avgInterval time.Duration) *scheduler {
+	return &scheduler{
+		rdb:         r,
+		done:        make(chan struct{}),
+		avgInterval: avgInterval,
+	}
+}
+
+func (s *scheduler) terminate() {
+	log.Println("[INFO] Scheduler shutting down...")
+	// Signal the scheduler goroutine to stop polling.
+	s.done <- struct{}{}
+}
+
+// start starts the "scheduler" goroutine.
+func (s *scheduler) start() {
+	go func() {
+		for {
+			select {
+			case <-s.done:
+				log.Println("[INFO] Scheduler done.")
+				return
+			case <-time.After(s.avgInterval):
+				s.exec()
+			}
+		}
+	}()
+}
+
+func (s *scheduler) exec() {
+	if err := s.rdb.CheckAndEnqueue(); err != nil {
+		log.Printf("[ERROR] could not forward scheduled tasks: %v\n", err)
+	}
+}