Re-render smartctl service file on config changed (#262)

src/service.py

@@ -136,7 +136,7 @@ def _render_service(self, params: Dict[str, str]) -> bool:
         return write_to_file(self.exporter_service_path, content)
 
     def render_config(self) -> bool:
-        """Render exporter config file.."""
+        """Render exporter config file."""
         if self.exporter_config_path is not None:
             content = self._render_config_content()
             return write_to_file(self.exporter_config_path, content, mode=0o600)
@@ -287,6 +287,19 @@ def render_service(self) -> bool:
         )
         return service_rendered
 
+    def render_config(self) -> bool:
+        """Override base render_config to render the service file.
+
+        This is because smartctl_exporter doesn't support providing config file.
+        The config options need to be provided as flags while exectuting
+        smartctl_exporter. So, the service file must be re-rendered when a config
+        value is changed.
+        """
+        service_rendered = self.render_service()
+        if service_rendered:
+            systemd.daemon_reload()
+        return service_rendered
+
     @staticmethod
     def hw_tools() -> List[HWTool]:
         """Return list hardware tools to watch."""

tests/unit/test_service.py

@@ -585,6 +585,10 @@ class TestSmartMetricExporter(unittest.TestCase):
 
     def setUp(self) -> None:
         """Set up harness for each test case."""
+        systemd_lib_patcher = mock.patch.object(service, "systemd")
+        self.mock_systemd = systemd_lib_patcher.start()
+        self.addCleanup(systemd_lib_patcher.stop)
+
         search_path = pathlib.Path(f"{__file__}/../../..").resolve()
         self.mock_config = {
             "smartctl-exporter-port": 10201,
@@ -608,6 +612,20 @@ def test_render_service(self):
             }
         )
 
+    @parameterized.expand(
+        [
+            (True,),
+            (False,),
+        ]
+    )
+    def test_render_config(self, service_render_success):
+        """Test render config."""
+        self.exporter.render_service = mock.MagicMock()
+        self.exporter.render_service.return_value = service_render_success
+
+        result = self.exporter.render_config()
+        self.assertEqual(result, service_render_success)
+
     def test_hw_tools(self):
         self.assertEqual(self.exporter.hw_tools(), [HWTool.SMARTCTL])