Close provider on ipfs shutdown

License: MIT
Signed-off-by: Michael Avila <davidmichaelavila@gmail.com>

offline.go

@@ -14,3 +14,7 @@ func (op *offlineProvider) Run() {}
 func (op *offlineProvider) Provide(cid cid.Cid) error {
 	return nil
 }
+
+func (op *offlineProvider) Close() error {
+	return nil
+}

provider.go

@@ -20,6 +20,8 @@ type Provider interface {
 	Run()
 	// Provide takes a cid and makes an attempt to announce it to the network
 	Provide(cid.Cid) error
+	// Close stops the provider
+	Close() error
 }
 
 type provider struct {
@@ -39,6 +41,12 @@ func NewProvider(ctx context.Context, queue *Queue, contentRouting routing.Conte
 	}
 }
 
+// Close stops the provider
+func (p *provider) Close() error {
+	p.queue.Close()
+	return nil
+}
+
 // Start workers to handle provide requests.
 func (p *provider) Run() {
 	p.handleAnnouncements()

queue.go

@@ -27,6 +27,8 @@ type Queue struct {
 	ds      datastore.Datastore // Must be threadsafe
 	dequeue chan cid.Cid
 	enqueue chan cid.Cid
+	close   context.CancelFunc
+	closed  chan struct{}
 }
 
 // NewQueue creates a queue for cids
@@ -36,19 +38,29 @@ func NewQueue(ctx context.Context, name string, ds datastore.Datastore) (*Queue,
 	if err != nil {
 		return nil, err
 	}
+	cancelCtx, cancel := context.WithCancel(ctx)
 	q := &Queue{
 		name:    name,
-		ctx:     ctx,
+		ctx:     cancelCtx,
 		head:    head,
 		tail:    tail,
 		ds:      namespaced,
 		dequeue: make(chan cid.Cid),
 		enqueue: make(chan cid.Cid),
+		close:   cancel,
+		closed:  make(chan struct{}, 1),
 	}
 	q.work()
 	return q, nil
 }
 
+// Close stops the queue
+func (q *Queue) Close() error {
+	q.close()
+	<-q.closed
+	return nil
+}
+
 // Enqueue puts a cid in the queue
 func (q *Queue) Enqueue(cid cid.Cid) {
 	select {
@@ -103,6 +115,10 @@ func (q *Queue) work() {
 		var k datastore.Key = datastore.Key{}
 		var c cid.Cid = cid.Undef
 
+		defer func() {
+			close(q.closed)
+		}()
+
 		for {
 			if c == cid.Undef {
 				k, c = q.nextEntry()