[#642] writecache: Remove usage of close channel in badger

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

pkg/local_object_storage/writecache/writecachebadger/flush.go

@@ -39,18 +39,16 @@ type collector struct {
 	cache     *cache
 	scheduled int
 	processed int
-	cancel    func()
 }
 
-func (c *collector) Send(buf *z.Buffer) error {
+func (c *collector) send(ctx context.Context, cancel func(), buf *z.Buffer) error {
 	list, err := badger.BufferToKVList(buf)
 	if err != nil {
 		return err
 	}
 	for _, kv := range list.Kv {
 		select {
-		case <-c.cache.closeCh:
-			c.cancel()
+		case <-ctx.Done():
 			return nil
 		default:
 		}
@@ -58,7 +56,7 @@ func (c *collector) Send(buf *z.Buffer) error {
 			return nil
 		}
 		if c.scheduled >= flushBatchSize {
-			c.cancel()
+			cancel()
 			return nil
 		}
 		if got, want := len(kv.Key), len(internalKey{}); got != want {
@@ -90,8 +88,7 @@ func (c *collector) Send(buf *z.Buffer) error {
 			data: val,
 			obj:  obj,
 		}:
-		case <-c.cache.closeCh:
-			c.cancel()
+		case <-ctx.Done():
 			return nil
 		}
 	}
@@ -99,10 +96,10 @@ func (c *collector) Send(buf *z.Buffer) error {
 }
 
 // runFlushLoop starts background workers which periodically flush objects to the blobstor.
-func (c *cache) runFlushLoop() {
+func (c *cache) runFlushLoop(ctx context.Context) {
 	for i := 0; i < c.workersCount; i++ {
 		c.wg.Add(1)
-		go c.workerFlushSmall()
+		go c.workerFlushSmall(ctx)
 	}
 
 	c.wg.Add(1)
@@ -115,19 +112,19 @@ func (c *cache) runFlushLoop() {
 		for {
 			select {
 			case <-tt.C:
-				c.flushSmallObjects()
+				c.flushSmallObjects(ctx)
 				tt.Reset(defaultFlushInterval)
-			case <-c.closeCh:
+			case <-ctx.Done():
 				return
 			}
 		}
 	}()
 }
 
-func (c *cache) flushSmallObjects() {
+func (c *cache) flushSmallObjects(ctx context.Context) {
 	for {
 		select {
-		case <-c.closeCh:
+		case <-ctx.Done():
 			return
 		default:
 		}
@@ -144,14 +141,15 @@ func (c *cache) flushSmallObjects() {
 			c.modeMtx.RUnlock()
 			return
 		}
-		ctx, cancel := context.WithCancel(context.TODO())
+		ctx, cancel := context.WithCancel(ctx)
 		coll := collector{
-			cache:  c,
-			cancel: cancel,
+			cache: c,
 		}
 		stream := c.db.NewStream()
 		// All calls to Send are done by a single goroutine
-		stream.Send = coll.Send
+		stream.Send = func(buf *z.Buffer) error {
+			return coll.send(ctx, cancel, buf)
+		}
 		if err := stream.Orchestrate(ctx); err != nil {
 			c.log.Debug(fmt.Sprintf(
 				"error during flushing object from wc: %s", err))
@@ -176,7 +174,7 @@ func (c *cache) reportFlushError(msg string, addr string, err error) {
 }
 
 // workerFlushSmall writes small objects to the main storage.
-func (c *cache) workerFlushSmall() {
+func (c *cache) workerFlushSmall(ctx context.Context) {
 	defer c.wg.Done()
 
 	var objInfo objectInfo
@@ -184,11 +182,11 @@ func (c *cache) workerFlushSmall() {
 		// Give priority to direct put.
 		select {
 		case objInfo = <-c.flushCh:
-		case <-c.closeCh:
+		case <-ctx.Done():
 			return
 		}
 
-		err := c.flushObject(context.TODO(), objInfo.obj, objInfo.data, writecache.StorageTypeDB)
+		err := c.flushObject(ctx, objInfo.obj, objInfo.data, writecache.StorageTypeDB)
 		if err == nil {
 			c.deleteFromDB([]internalKey{addr2key(objInfo.addr)})
 		}