feat: add swap usage query

selfprivacy_api/graphql/queries/monitoring.py

@@ -38,6 +38,13 @@ class MemoryMonitoring:
 
         return MonitoringQueries.memory_usage_overall(self.start, self.end, self.step)
 
+    @strawberry.field
+    def swap_usage_overall(self) -> MonitoringValuesResult:
+        if Prometheus().get_status() != ServiceStatus.ACTIVE:
+            return MonitoringQueryError(error="Prometheus is not running")
+
+        return MonitoringQueries.swap_usage_overall(self.start, self.end, self.step)
+
     @strawberry.field
     def average_usage_by_service(self) -> MonitoringMetricsResult:
         if Prometheus().get_status() != ServiceStatus.ACTIVE:

selfprivacy_api/utils/monitoring.py

@@ -264,6 +264,52 @@ class MonitoringQueries:
             )
         )
 
+    @staticmethod
+    def swap_usage_overall(
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
+        step: int = 60,  # seconds
+    ) -> MonitoringValuesResult:
+        """
+        Get swap memory usage.
+
+        Args:
+            start (datetime, optional): The start time.
+                Defaults to 20 minutes ago if not provided.
+            end (datetime, optional): The end time.
+                Defaults to current time if not provided.
+            step (int): Interval in seconds for querying swap memory usage data.
+        """
+
+        if start is None:
+            start = datetime.now() - timedelta(minutes=20)
+
+        if end is None:
+            end = datetime.now()
+
+        start_timestamp = int(start.timestamp())
+        end_timestamp = int(end.timestamp())
+
+        query = (
+            "100 - (100 * (node_memory_SwapFree_bytes / node_memory_SwapTotal_bytes))"
+        )
+
+        data = MonitoringQueries._send_range_query(
+            query, start_timestamp, end_timestamp, step, result_type="matrix"
+        )
+
+        if isinstance(data, MonitoringQueryError):
+            return data
+
+        return MonitoringValues(
+            values=list(
+                map(
+                    MonitoringQueries._prometheus_value_to_monitoring_value,
+                    data["result"][0]["values"],
+                )
+            )
+        )
+
     @staticmethod
     def memory_usage_max_by_slice(
         start: Optional[datetime] = None,