Refactor redfish login and logout methods.

redfish context manager could potentially failed during __enter__ which
might causes the __exit__ function never called. We should ensure the
redfish client is logged out in any exception. This can be achieved by
adding a finally block to the try-except block.

prometheus_hardware_exporter/collector.py

@@ -995,41 +995,51 @@ def fetch(self) -> List[Payload]:
         if not service_status:
             return payloads
 
+        redfish_helper = None
         try:
-            with RedfishHelper(self.config) as redfish_helper:
-                payloads.append(Payload(name="redfish_call_success", value=1.0))
-
-                processor_count: Dict[str, int]
-                processor_data: Dict[str, List]
-                storage_controller_count: Dict[str, int]
-                storage_controller_data: Dict[str, List]
-                storage_drive_count: Dict[str, int]
-                storage_drive_data: Dict[str, List]
-                memory_dimm_count: Dict[str, int]
-                memory_dimm_data: Dict[str, List]
-
-                sensor_data: Dict[str, List] = redfish_helper.get_sensor_data()
-                processor_count, processor_data = redfish_helper.get_processor_data()
-                (
-                    storage_controller_count,
-                    storage_controller_data,
-                ) = redfish_helper.get_storage_controller_data()
-                network_adapter_count: Dict[str, Any] = redfish_helper.get_network_adapter_data()
-                chassis_data: Dict[str, Dict] = redfish_helper.get_chassis_data()
-                storage_drive_count, storage_drive_data = redfish_helper.get_storage_drive_data()
-                memory_dimm_count, memory_dimm_data = redfish_helper.get_memory_dimm_data()
-                smart_storage_health_data: Dict[str, Any] = (
-                    redfish_helper.get_smart_storage_health_data()
-                )
+            redfish_helper = RedfishHelper(self.config)
+            redfish_helper.login()
+            payloads.append(Payload(name="redfish_call_success", value=1.0))
+
+            processor_count: Dict[str, int]
+            processor_data: Dict[str, List]
+            storage_controller_count: Dict[str, int]
+            storage_controller_data: Dict[str, List]
+            storage_drive_count: Dict[str, int]
+            storage_drive_data: Dict[str, List]
+            memory_dimm_count: Dict[str, int]
+            memory_dimm_data: Dict[str, List]
+
+            sensor_data: Dict[str, List] = redfish_helper.get_sensor_data()
+            processor_count, processor_data = redfish_helper.get_processor_data()
+            (
+                storage_controller_count,
+                storage_controller_data,
+            ) = redfish_helper.get_storage_controller_data()
+            network_adapter_count: Dict[str, Any] = redfish_helper.get_network_adapter_data()
+            chassis_data: Dict[str, Dict] = redfish_helper.get_chassis_data()
+            storage_drive_count, storage_drive_data = redfish_helper.get_storage_drive_data()
+            memory_dimm_count, memory_dimm_data = redfish_helper.get_memory_dimm_data()
+            smart_storage_health_data: Dict[str, Any] = (
+                redfish_helper.get_smart_storage_health_data()
+            )
         except (
             ConnectionError,
             InvalidCredentialsError,
             RetriesExhaustedError,
             SessionCreationError,
         ) as err:
-            logger.exception("Exception occurred while getting redfish object: %s", err)
+            logger.exception("Exception occurred while using redfish object: %s", err)
+            payloads.append(Payload(name="redfish_call_success", value=0.0))
+            return payloads
+        except Exception as err:  # pylint: disable=W0718
+            logger.exception("Exception occurred while using redfish object: %s", err)
             payloads.append(Payload(name="redfish_call_success", value=0.0))
             return payloads
+        finally:
+            # Guarding against `RedfishHelper` crashes, and `redfish_helper` remains `None`
+            if redfish_helper:
+                redfish_helper.logout()
 
         metrics: Dict[str, Any] = {
             "sensor_data": sensor_data,

prometheus_hardware_exporter/collectors/redfish.py

@@ -7,7 +7,6 @@
 from cachetools.func import ttl_cache
 from redfish import redfish_client
 from redfish.rest.v1 import (
-    HttpClient,
     InvalidCredentialsError,
     RestResponse,
     RetriesExhaustedError,
@@ -76,30 +75,32 @@ def __init__(self, config: Config) -> None:
         self.password = config.redfish_password
         self.timeout = config.redfish_client_timeout
         self.max_retry = config.redfish_client_max_retry
-        self.redfish_obj: HttpClient
-
-    def __enter__(self) -> Self:
-        """Login to redfish while entering context manager."""
-        logger.debug("(service) Trying to login to redfish service ...")
         self.redfish_obj = redfish_client(
             base_url=self.host,
             username=self.username,
             password=self.password,
             timeout=self.timeout,
             max_retry=self.max_retry,
         )
-        self.redfish_obj.login(auth="session")
+
+    def __enter__(self) -> Self:
+        """Login as a context manager."""
+        self.login()
         return self
 
     def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None:
-        """Logout from redfish while exiting context manager."""
+        """Logout as a context manager."""
         self.logout()
 
+    def login(self) -> None:
+        """Login to redfish."""
+        logger.debug("(service) Trying to login to redfish service ...")
+        self.redfish_obj.login(auth="session")
+
     def logout(self) -> None:
         """Logout from redfish."""
-        if self.redfish_obj is not None:
-            self.redfish_obj.logout()
-            logger.debug("(service) Logged out from redfish service ...")
+        self.redfish_obj.logout()
+        logger.debug("(service) Logged out from redfish service ...")
 
     def get_sensor_data(self) -> Dict[str, List]:
         """Get sensor data.
@@ -136,12 +137,12 @@ def _retrieve_redfish_sensor_data(self) -> List[Any]:
         sensors = redfish_utilities.get_sensors(self.redfish_obj)
         return sensors
 
-    def _verify_redfish_call(self, redfish_obj: HttpClient, uri: str) -> Optional[Dict[str, Any]]:
+    def _verify_redfish_call(self, uri: str) -> Optional[Dict[str, Any]]:
         """Return REST response for GET request API call on the URI.
 
         Returns None if URI isn't present.
         """
-        resp: RestResponse = redfish_obj.get(uri)
+        resp: RestResponse = self.redfish_obj.get(uri)
         if resp.status == 200:
             return resp.dict
         logger.debug("Not able to query from URI: %s.", uri)
@@ -343,7 +344,7 @@ def get_network_adapter_data(self) -> Dict[str, int]:
             # eg: /redfish/v1/Chassis/1/NetworkAdapters
             network_adapters_root_uri = network_adapters_root_uri_pattern.format(chassis_id)
             network_adapters: Optional[Dict[str, Any]] = self._verify_redfish_call(
-                self.redfish_obj, network_adapters_root_uri
+                network_adapters_root_uri
             )
             if not network_adapters:
                 logger.debug("No network adapters could be found on chassis id: %s", chassis_id)
@@ -579,7 +580,7 @@ def get_smart_storage_health_data(self) -> Dict[str, Any]:
         for chassis_id in chassis_ids:
             smart_storage_uri = smart_storage_root_uri_pattern.format(chassis_id)
             smart_storage_data: Optional[Dict[str, Any]] = self._verify_redfish_call(
-                self.redfish_obj, smart_storage_uri
+                smart_storage_uri
             )
             if not smart_storage_data:
                 logger.debug("Smart Storage URI endpoint not found for chassis ID: %s", chassis_id)

tests/unit/test_collector.py

@@ -635,12 +635,17 @@ def _discover(*args, **kwargs):
         mock_redfish_client.assert_not_called()
 
     @patch("prometheus_hardware_exporter.collector.logger")
+    @patch("prometheus_hardware_exporter.collector.RedfishHelper")
     @patch("prometheus_hardware_exporter.collectors.redfish.redfish_client")
     @patch(
         "prometheus_hardware_exporter.collectors.redfish.RedfishHelper.get_cached_discover_method"
     )
     def test_redfish_no_login(
-        self, mock_get_cached_discover_method, mock_redfish_client, mock_logger
+        self,
+        mock_get_cached_discover_method,
+        mock_redfish_client,
+        mock_redfish_helper,
+        mock_logger,
     ):
         """Test redfish collector when redfish login doesn't work."""
 
@@ -652,29 +657,33 @@ def _discover(*args, **kwargs):
 
         mock_get_cached_discover_method.side_effect = cached_discover
         redfish_collector = RedfishCollector(Mock())
-        redfish_collector.redfish_helper = Mock()
+
+        mock_helper = Mock()
+        mock_redfish_helper.return_value = mock_helper
 
         for err in [
+            Exception(),
             ConnectionError(),
             InvalidCredentialsError(),
             SessionCreationError(),
             RetriesExhaustedError(),
         ]:
-            mock_redfish_client.side_effect = err
+            mock_helper.login.side_effect = err
             payloads = redfish_collector.collect()
 
             # Check whether these 2 payloads are present
             # redfish_service_available which is set to value 1
             # redfish_call_success which is set to value 0
             self.assertEqual(len(list(payloads)), 2)
             mock_logger.exception.assert_called_with(
-                "Exception occurred while getting redfish object: %s", err
+                "Exception occurred while using redfish object: %s", err
             )
-        mock_redfish_client.assert_called()
+        mock_redfish_helper.assert_called()
+        mock_helper.login.assert_called()
+        mock_helper.logout.assert_called()
 
     @patch("prometheus_hardware_exporter.collector.logger")
-    @patch("prometheus_hardware_exporter.collectors.redfish.RedfishHelper.__exit__")
-    @patch("prometheus_hardware_exporter.collectors.redfish.RedfishHelper.__enter__")
+    @patch("prometheus_hardware_exporter.collector.RedfishHelper")
     @patch("prometheus_hardware_exporter.collectors.redfish.redfish_client")
     @patch(
         "prometheus_hardware_exporter.collectors.redfish.RedfishHelper.get_cached_discover_method"
@@ -683,8 +692,7 @@ def test_redfish_installed_and_okay(
         self,
         mock_get_cached_discover_method,
         mock_redfish_client,
-        mock_redfish_helper_enter,
-        mock_redfish_helper_exit,
+        mock_redfish_helper,
         mock_logger,
     ):
         """Test redfish collector and check if all metrics are present in payload."""
@@ -700,7 +708,7 @@ def _discover(*args, **kwargs):
         redfish_collector = RedfishCollector(Mock())
 
         mock_helper = Mock()
-        mock_redfish_helper_enter.return_value = mock_helper
+        mock_redfish_helper.return_value = mock_helper
 
         mock_get_sensor_data = Mock()
         mock_get_processor_data = Mock()
@@ -861,6 +869,8 @@ def _discover(*args, **kwargs):
         for payload in payloads:
             self.assertIn(payload.name, available_metrics)
 
+        mock_helper.login.assert_called()
+        mock_helper.logout.assert_called()
         mock_logger.warning.assert_called_with(
             "Failed to get %s via redfish", "network_adapter_count"
         )