unified task package

common/task/periodic.go

@@ -0,0 +1,69 @@
+package task
+
+import (
+	"sync"
+	"time"
+)
+
+// Periodic is a task that runs periodically.
+type Periodic struct {
+	// Interval of the task being run
+	Interval time.Duration
+	// Execute is the task function
+	Execute func() error
+	// OnFailure will be called when Execute returns non-nil error
+	OnError func(error)
+
+	access sync.Mutex
+	timer  *time.Timer
+	closed bool
+}
+
+func (t *Periodic) checkedExecute() error {
+	t.access.Lock()
+	defer t.access.Unlock()
+
+	if t.closed {
+		return nil
+	}
+
+	if err := t.Execute(); err != nil {
+		return err
+	}
+
+	t.timer = time.AfterFunc(t.Interval, func() {
+		if err := t.checkedExecute(); err != nil && t.OnError != nil {
+			t.OnError(err)
+		}
+	})
+
+	return nil
+}
+
+// Start implements common.Runnable. Start must not be called multiple times without Close being called.
+func (t *Periodic) Start() error {
+	t.access.Lock()
+	t.closed = false
+	t.access.Unlock()
+
+	if err := t.checkedExecute(); err != nil {
+		t.closed = true
+		return err
+	}
+
+	return nil
+}
+
+// Close implements common.Closable.
+func (t *Periodic) Close() error {
+	t.access.Lock()
+	defer t.access.Unlock()
+
+	t.closed = true
+	if t.timer != nil {
+		t.timer.Stop()
+		t.timer = nil
+	}
+
+	return nil
+}