[fix] Don't evaluate threshold for historical data #666

openwisp_monitoring/monitoring/base/models.py

@@ -382,6 +382,10 @@ def check_threshold(self, value, time=None, retention_policy=None, send_alert=Tr
             alert_settings = self.alertsettings
         except ObjectDoesNotExist:
             return
+        if time and alert_settings._is_historical_data(time):
+            # Device is uploading historical data (could be due to a network outage).
+            # We don't want to send alerts in this scenario.
+            return
         is_healthy_changed = self._set_is_healthy(alert_settings, value)
         tolerance_healthy_changed_first_time = self._set_is_healthy_tolerant(
             alert_settings, value, time, retention_policy, send_alert
@@ -942,6 +946,13 @@ def operator(self):
             return self.config_dict["operator"]
         return self.custom_operator
 
+    def _is_historical_data(self, time):
+        """
+        Data older than 5 minutes is considered historical data.
+        """
+        recent_time = timezone.now() - timedelta(minutes=5)
+        return time < recent_time
+
     def _value_crossed(self, current_value):
         threshold_value = self.threshold
         method = "__gt__" if self.operator == ">" else "__lt__"

openwisp_monitoring/monitoring/tests/test_monitoring_notifications.py

@@ -319,6 +319,40 @@ def test_object_check_threshold_crossed_for_long_time(self):
         self.assertEqual(om.is_healthy_tolerant, True)
         self.assertEqual(Notification.objects.count(), 2)
 
+    def test_object_check_threshold_crossed_historical_data(self):
+        """
+        Do not evaluate threshold crossed for historical data
+        """
+        self._create_admin()
+        om = self._create_object_metric(name="load")
+        self._create_alert_settings(
+            metric=om, custom_operator=">", custom_threshold=90, custom_tolerance=10
+        )
+
+        self._write_metric(om, 99, time=start_time - timedelta(minutes=120))
+        om.refresh_from_db()
+        self.assertEqual(om.is_healthy, True)
+        self.assertEqual(om.is_healthy_tolerant, True)
+        self.assertEqual(Notification.objects.count(), 0)
+
+        self._write_metric(om, 99, time=start_time - timedelta(minutes=61))
+        om.refresh_from_db()
+        self.assertEqual(om.is_healthy, True)
+        self.assertEqual(om.is_healthy_tolerant, True)
+        self.assertEqual(Notification.objects.count(), 0)
+
+        self._write_metric(om, 99, time=start_time - timedelta(minutes=60))
+        om.refresh_from_db()
+        self.assertEqual(om.is_healthy, True)
+        self.assertEqual(om.is_healthy_tolerant, True)
+        self.assertEqual(Notification.objects.count(), 0)
+
+        self._write_metric(om, 99, time=start_time - timedelta(minutes=10))
+        om.refresh_from_db()
+        self.assertEqual(om.is_healthy, False)
+        self.assertEqual(om.is_healthy_tolerant, False)
+        self.assertEqual(Notification.objects.count(), 1)
+
     def test_flapping_metric_with_tolerance(self):
         self._create_admin()
         om = self._create_object_metric(name="ping")