[VOL-4548] openonuAdapterGo - memory leak seen in long term tests

Change-Id: Ie3eb2048cebf8bf8b2f2a99ccd927d462000223a
diff --git a/internal/pkg/core/device_handler.go b/internal/pkg/core/device_handler.go
index 58d42b1..332861b 100755
--- a/internal/pkg/core/device_handler.go
+++ b/internal/pkg/core/device_handler.go
@@ -4497,3 +4497,50 @@
 	}
 	return tpPathFound
 }
+
+// PrepareForGarbageCollection - remove references to prepare for garbage collection
+func (dh *deviceHandler) PrepareForGarbageCollection(ctx context.Context, aDeviceID string) {
+	logger.Debugw(ctx, "prepare for garbage collection", log.Fields{"device-id": aDeviceID})
+
+	// Note: This function must be called as a goroutine to prevent blocking of further processing!
+	// first let the objects rest for some time to give all asynchronously started
+	// cleanup routines a chance to come to an end
+	time.Sleep(5 * time.Second)
+
+	if dh.pOnuTP != nil {
+		dh.pOnuTP.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pOnuMetricsMgr != nil {
+		dh.pOnuMetricsMgr.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pAlarmMgr != nil {
+		dh.pAlarmMgr.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pSelfTestHdlr != nil {
+		dh.pSelfTestHdlr.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pLockStateFsm != nil {
+		dh.pLockStateFsm.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pUnlockStateFsm != nil {
+		dh.pUnlockStateFsm.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pOnuUpradeFsm != nil {
+		dh.pOnuUpradeFsm.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	if dh.pOnuOmciDevice != nil {
+		dh.pOnuOmciDevice.PrepareForGarbageCollection(ctx, aDeviceID)
+	}
+	for k, v := range dh.UniVlanConfigFsmMap {
+		v.PrepareForGarbageCollection(ctx, aDeviceID)
+		delete(dh.UniVlanConfigFsmMap, k)
+	}
+	dh.pOnuOmciDevice = nil
+	dh.pOnuTP = nil
+	dh.pOnuMetricsMgr = nil
+	dh.pAlarmMgr = nil
+	dh.pSelfTestHdlr = nil
+	dh.pLockStateFsm = nil
+	dh.pUnlockStateFsm = nil
+	dh.pOnuUpradeFsm = nil
+}
diff --git a/internal/pkg/core/openonu.go b/internal/pkg/core/openonu.go
index f0da31b..44bfae0 100755
--- a/internal/pkg/core/openonu.go
+++ b/internal/pkg/core/openonu.go
@@ -344,34 +344,18 @@
 		if err := handler.resetFsms(ctx, true); err != nil {
 			errorsList = append(errorsList, err)
 		}
-		forceKvDelete := false
-
-		// Clear PM data on the KV store
-		if handler.pOnuMetricsMgr != nil {
-			if err := handler.pOnuMetricsMgr.ClearAllPmData(ctx); err != nil {
-				errorsList = append(errorsList, err)
-				forceKvDelete = true
-			}
-		} else {
-			forceKvDelete = true
-		}
-		if err := handler.deleteDevicePersistencyData(ctx); err != nil {
-			errorsList = append(errorsList, err)
-			forceKvDelete = true
-		}
 		for _, uni := range handler.uniEntityMap {
 			if handler.GetFlowMonitoringIsRunning(uni.UniID) {
 				handler.stopFlowMonitoringRoutine[uni.UniID] <- true
 				logger.Debugw(ctx, "sent stop signal to self flow monitoring routine", log.Fields{"device-id": device.Id})
 			}
 		}
-		//don't leave any garbage - even in error case
-		oo.deleteDeviceHandlerToMap(handler)
-		if forceKvDelete {
-			if err := oo.forceDeleteDeviceKvData(ctx, device.Id); err != nil {
-				errorsList = append(errorsList, err)
-			}
+		//don't leave any garbage in kv-store
+		if err := oo.forceDeleteDeviceKvData(ctx, device.Id); err != nil {
+			errorsList = append(errorsList, err)
 		}
+		oo.deleteDeviceHandlerToMap(handler)
+		go handler.PrepareForGarbageCollection(ctx, handler.DeviceID)
 
 		if len(errorsList) > 0 {
 			logger.Errorw(ctx, "one-or-more-error-during-device-delete", log.Fields{"device-id": device.Id})