refactor(goroutine): improve concurrency safety and testing (#122)

- Enable race condition detection in Go tests by adding `-race` flag
- Refactor `Queue` to use a local variable for `workerCount` with proper locking
- Refactor `Ring` to use a local variable for `count` with proper locking and defer unlocking
- Replace direct access to `busyWorkers` metric with `BusyWorkers()` method in tests

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Author: appleboy

.github/workflows/go.yml

@@ -66,7 +66,7 @@ jobs:
             ${{ runner.os }}-go-
       - name: Run Tests
         run: |
-          go test -v -covermode=atomic -coverprofile=coverage.out
+          go test -race -v -covermode=atomic -coverprofile=coverage.out
 
       - name: Run Benchmark
         run: |

queue.go

@@ -57,7 +57,10 @@ func NewQueue(opts ...Option) (*Queue, error) {
 
 // Start to enable all worker
 func (q *Queue) Start() {
-	if q.workerCount == 0 {
+	q.Lock()
+	count := q.workerCount
+	q.Unlock()
+	if count == 0 {
 		return
 	}
 	q.routineGroup.Run(func() {
@@ -262,7 +265,9 @@ func (q *Queue) handle(m *job.Message) error {
 
 // UpdateWorkerCount to update worker number dynamically.
 func (q *Queue) UpdateWorkerCount(num int) {
+	q.Lock()
 	q.workerCount = num
+	q.Unlock()
 	q.schedule()
 }
 

ring.go

@@ -37,7 +37,10 @@ func (s *Ring) Shutdown() error {
 	}
 
 	s.stopOnce.Do(func() {
-		if s.count > 0 {
+		s.Lock()
+		count := s.count
+		s.Unlock()
+		if count > 0 {
 			<-s.exit
 		}
 	})
@@ -75,10 +78,11 @@ func (s *Ring) Request() (core.QueuedMessage, error) {
 		return nil, ErrQueueHasBeenClosed
 	}
 
+	s.Lock()
+	defer s.Unlock()
 	if s.count == 0 {
 		return nil, ErrNoTaskInQueue
 	}
-	s.Lock()
 	data := s.taskQueue[s.head]
 	s.taskQueue[s.head] = nil
 	s.head = (s.head + 1) % len(s.taskQueue)
@@ -87,7 +91,6 @@ func (s *Ring) Request() (core.QueuedMessage, error) {
 	if n := len(s.taskQueue) / 2; n > 2 && s.count <= n {
 		s.resize(n)
 	}
-	s.Unlock()
 
 	return data, nil
 }

ring_test.go

@@ -142,7 +142,7 @@ func TestCancelJobAfterShutdown(t *testing.T) {
 	assert.NoError(t, q.Queue(m, job.AllowOption{Timeout: job.Time(100 * time.Millisecond)}))
 	q.Start()
 	time.Sleep(10 * time.Millisecond)
-	assert.Equal(t, 2, int(q.metric.busyWorkers))
+	assert.Equal(t, 2, q.BusyWorkers())
 	q.Release()
 }