[#424] writecache: Drop metrics when close

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/engine/writecache.go

@@ -102,3 +102,7 @@ func (m *writeCacheMetrics) Evict(st writecache.StorageType) {
 	m.metrics.DecActualCount(m.shardID, st.String())
 	m.metrics.IncOperationCounter(m.shardID, "Evict", metrics.NullBool{}, st.String())
 }
+
+func (m *writeCacheMetrics) Close() {
+	m.metrics.Close(m.shardID)
+}

pkg/local_object_storage/writecache/metrics.go

@@ -28,6 +28,7 @@ type Metrics interface {
 	SetEstimateSize(db, fstree uint64)
 	SetMode(m mode.Mode)
 	SetActualCounters(db, fstree uint64)
+	Close()
 }
 
 type metricsStub struct{}
@@ -47,3 +48,5 @@ func (s *metricsStub) SetActualCounters(uint64, uint64) {}
 func (s *metricsStub) Flush(bool, StorageType) {}
 
 func (s *metricsStub) Evict(StorageType) {}
+
+func (s *metricsStub) Close() {}

pkg/local_object_storage/writecache/writecache.go

@@ -170,5 +170,6 @@ func (c *cache) Close() error {
 			c.db = nil
 		}
 	}
+	c.metrics.Close()
 	return nil
 }

pkg/metrics/writecache.go

@@ -34,6 +34,8 @@ type WriteCacheMetrics interface {
 	SetMode(shardID string, mode string)
 
 	IncOperationCounter(shardID string, operation string, success NullBool, storageType string)
+
+	Close(shardID string)
 }
 
 type writeCacheMetrics struct {
@@ -155,6 +157,14 @@ func (m *writeCacheMetrics) IncOperationCounter(shardID string, operation string
 	}).Inc()
 }
 
+func (m *writeCacheMetrics) Close(shardID string) {
+	m.SetMode(shardID, "CLOSED")
+	m.methodDuration.DeletePartialMatch(prometheus.Labels{wcShardID: shardID})
+	m.operationCounter.DeletePartialMatch(prometheus.Labels{wcShardID: shardID})
+	m.actualCount.DeletePartialMatch(prometheus.Labels{wcShardID: shardID})
+	m.estimatedSize.DeletePartialMatch(prometheus.Labels{wcShardID: shardID})
+}
+
 func newWCGaugeVec(name, help string, labels []string) *prometheus.GaugeVec {
 	return metrics.NewGaugeVec(prometheus.GaugeOpts{
 		Namespace: namespace,