Merge pull request #531 from PalanQu/queue-stop

feat: support Stop() in queue

Author: asciimoo

queue/queue.go

@@ -30,7 +30,8 @@ type Queue struct {
 	Threads int
 	storage Storage
 	wake    chan struct{}
-	mut     sync.Mutex // guards wake
+	mut     sync.Mutex // guards wake and running
+	running bool
 }
 
 // InMemoryQueueStorage is the default implementation of the Storage interface.
@@ -62,6 +63,7 @@ func New(threads int, s Storage) (*Queue, error) {
 	return &Queue{
 		Threads: threads,
 		storage: s,
+		running: true,
 	}, nil
 }
 
@@ -122,11 +124,12 @@ func (q *Queue) Size() (int, error) {
 // The given Storage must not be used directly while Run blocks.
 func (q *Queue) Run(c *colly.Collector) error {
 	q.mut.Lock()
-	if q.wake != nil {
+	if q.wake != nil && q.running == true {
 		q.mut.Unlock()
 		panic("cannot call duplicate Queue.Run")
 	}
 	q.wake = make(chan struct{})
+	q.running = true
 	q.mut.Unlock()
 
 	requestc := make(chan *colly.Request)
@@ -139,6 +142,13 @@ func (q *Queue) Run(c *colly.Collector) error {
 	return <-errc
 }
 
+// Stop will stop the running queue
+func (q *Queue) Stop() {
+	q.mut.Lock()
+	q.running = false
+	q.mut.Unlock()
+}
+
 func (q *Queue) loop(c *colly.Collector, requestc chan<- *colly.Request, complete <-chan struct{}, errc chan<- error) {
 	var active int
 	for {
@@ -147,7 +157,7 @@ func (q *Queue) loop(c *colly.Collector, requestc chan<- *colly.Request, complet
 			errc <- err
 			break
 		}
-		if size == 0 && active == 0 {
+		if size == 0 && active == 0 || !q.running {
 			// Terminate when
 			//   1. No active requests
 			//   2. Emtpy queue