fix the warnings for go test --race

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
       run: go get -u github.com/mattn/goveralls
 
     - name: Test
-      run: go test -v -covermode=count -coverprofile=coverage.out ./...
+      run: go test --race -v -covermode=atomic -coverprofile=coverage.out ./...
 
     - name: Update Coveralls
       env:

tasks.go

@@ -93,6 +93,8 @@ import (
 // Task contains the scheduled task details and control mechanisms. This struct is used during the creation of tasks.
 // It allows users to control how and when tasks are executed.
 type Task struct {
+	sync.Mutex
+
 	// id is the Unique ID created for each task. This ID is generated by the Add() function.
 	id string
 
@@ -139,6 +141,14 @@ type Task struct {
 	cancel context.CancelFunc
 }
 
+// safeOps safely change task's data
+func (t *Task) safeOps(f func()) {
+	t.Lock()
+	defer t.Unlock()
+
+	f()
+}
+
 // Scheduler stores the internal task list and provides an interface for task management.
 type Scheduler struct {
 	sync.RWMutex
@@ -243,6 +253,10 @@ func (schd *Scheduler) Del(name string) {
 
 	// Stop the task
 	defer t.cancel()
+
+	t.Lock()
+	defer t.Unlock()
+
 	if t.timer != nil {
 		defer t.timer.Stop()
 	}
@@ -290,7 +304,9 @@ func (schd *Scheduler) Stop() {
 func (schd *Scheduler) scheduleTask(t *Task) {
 	select {
 	case <-time.After(time.Until(t.StartAfter)):
-		t.timer = time.AfterFunc(t.Interval, func() { schd.execTask(t) })
+		t.safeOps(func() {
+			t.timer = time.AfterFunc(t.Interval, func() { schd.execTask(t) })
+		})
 		return
 	case <-t.ctx.Done():
 		return
@@ -309,6 +325,8 @@ func (schd *Scheduler) execTask(t *Task) {
 		}
 	}()
 	if !t.RunOnce {
-		t.timer.Reset(t.Interval)
+		t.safeOps(func() {
+			t.timer.Reset(t.Interval)
+		})
 	}
 }