Configure Grafana DashBoards dinamically (#392)

If an exporter is not present, there is no need of rendering a
dashboard for an specific exporter. E.g: a machine without NVIDIA
doesn't need to render an empty Dashboard for GPU

Fix: #366

src/charm.py

@@ -55,6 +55,7 @@ def __init__(self, *args: Any) -> None:
             self,
             refresh_events=[self.on.config_changed, self.on.upgrade_charm],
             scrape_configs=self._scrape_config,
+            dashboard_dirs=self._dashboards(),
         )
 
         self.num_cos_agent_relations = self.get_num_cos_agent_relations("cos-agent")
@@ -326,6 +327,18 @@ def _scrape_config(self) -> List[Dict[str, Any]]:
                 )
         return scrape_config
 
+    def _dashboards(self) -> List[str]:
+        """Create the dashboards as needed."""
+        dashboards = []
+        for exporter in self.exporters:
+            if isinstance(exporter, HardwareExporter):
+                dashboards.append("./src/dashboards_hardware_exporter")
+            if isinstance(exporter, SmartCtlExporter):
+                dashboards.append("./src/dashboards_smart_ctl")
+            if isinstance(exporter, DCGMExporter):
+                dashboards.append("./src/dashboards_dcgm")
+        return dashboards
+
     @property
     def cos_agent_related(self) -> bool:
         """Return True if cos-agent relation is present."""

tests/unit/test_charm.py

@@ -48,7 +48,8 @@ def _get_notice_count(self, hook):
                 notice_count += 1
         return notice_count
 
-    def test_harness(self) -> None:
+    @mock.patch("charm.HardwareObserverCharm._dashboards")
+    def test_harness(self, _) -> None:
         """Test charm initialize."""
         self.harness.begin()
         self.assertFalse(self.harness.charm._stored.resource_installed)
@@ -77,11 +78,19 @@ def test_harness(self) -> None:
             ),
         ]
     )
+    @mock.patch("charm.HardwareObserverCharm._dashboards")
     @mock.patch("charm.DCGMExporter")
     @mock.patch("charm.SmartCtlExporter")
     @mock.patch("charm.HardwareExporter")
     def test_exporters(
-        self, _, stored_tools, expect, mock_hw_exporter, mock_smart_exporter, mock_dcgm_exporter
+        self,
+        _,
+        stored_tools,
+        expect,
+        mock_hw_exporter,
+        mock_smart_exporter,
+        mock_dcgm_exporter,
+        mock_dashboards,
     ):
         with mock.patch(
             "charm.HardwareObserverCharm.stored_tools",
@@ -452,6 +461,7 @@ def test_update_status(  # noqa: C901
             ),
         ]
     )
+    @mock.patch("charm.HardwareObserverCharm._dashboards")
     @mock.patch(
         "charm.detect_available_tools",
     )
@@ -462,6 +472,7 @@ def test_detect_hardware_action(
         detected_available_tools,
         expect_output,
         mock_detect_available_tools,
+        _,
     ) -> None:
         """Test action detect-hardware."""
         mock_detect_available_tools.return_value = detected_available_tools
@@ -793,7 +804,8 @@ def test_validate_configs(
             result = self.harness.charm.validate_configs()
             self.assertEqual(result, expect)
 
-    def test_stored_tools_remove_legacy_smartctl(self):
+    @mock.patch("charm.HardwareObserverCharm._dashboards")
+    def test_stored_tools_remove_legacy_smartctl(self, _):
         self.harness.begin()
         self.harness.charm._stored.stored_tools = {"smartctl"}
         assert self.harness.charm.stored_tools == set()
@@ -832,3 +844,34 @@ def test_scrape_config_no_specific_hardware(
             {"scrape_timeout": "10s"},
             {"metrics_path": "/metrics", "static_configs": [{"targets": ["localhost:10201"]}]},
         ]
+
+    @mock.patch("service.get_bmc_address")
+    @mock.patch("charm.HardwareObserverCharm.exporters", new_callable=mock.PropertyMock)
+    def test_dashboards(self, mock_exporters, _):
+        self.harness.begin()
+        config = self.harness.charm.model.config
+        hw_exporter = HardwareExporter(Path(), config, set())
+        smartctl_exporter = SmartCtlExporter(config)
+        dcgm_exporter = DCGMExporter(config)
+
+        mock_exporters.return_value = [hw_exporter, smartctl_exporter, dcgm_exporter]
+
+        assert self.harness.charm._dashboards() == [
+            "./src/dashboards_hardware_exporter",
+            "./src/dashboards_smart_ctl",
+            "./src/dashboards_dcgm",
+        ]
+
+    @mock.patch("charm.HardwareObserverCharm.exporters", new_callable=mock.PropertyMock)
+    def test_dashboards_no_specific_hardware(
+        self,
+        mock_exporters,
+    ):
+        # simulate a hardware that does not have NVIDIA or tools to install hw exporter
+        self.harness.begin()
+        config = self.harness.charm.model.config
+        smartctl_exporter = SmartCtlExporter(config)
+
+        mock_exporters.return_value = [smartctl_exporter]
+
+        assert self.harness.charm._dashboards() == ["./src/dashboards_smart_ctl"]

tests/unit/test_hw_tools.py

@@ -125,9 +125,14 @@ def test_make_executable_error_handling(self, mock_os):
 
 class TestHWToolHelper(unittest.TestCase):
     def setUp(self):
+        mock_dashboards = mock.patch.object(HardwareObserverCharm, "_dashboards")
+        self.mock_dashboards = mock_dashboards.start()
+
         self.harness = ops.testing.Harness(HardwareObserverCharm)
         self.harness.begin()
+
         self.addCleanup(self.harness.cleanup)
+        self.addCleanup(mock_dashboards.stop)
 
         self.hw_tool_helper = HWToolHelper()