DashboardScene: Add macro for interpolating __dashboard variable (#78172)

* DashbaordScene: Add macro for interpoladint __dashboard variable

* Review

* Test fix

* Test fix

public/app/features/dashboard-scene/scene/DashboardMacro.ts

@@ -0,0 +1,40 @@
+import { FormatVariable, SceneObject, sceneUtils } from '@grafana/scenes';
+
+import { getDashboardSceneFor } from '../utils/utils';
+
+/**
+ * Handles expressions like ${__dashboard.uid}
+ */
+class DashboardMacro implements FormatVariable {
+  public state: { name: string; type: string };
+
+  public constructor(
+    name: string,
+    private _sceneObject: SceneObject
+  ) {
+    this.state = { name: name, type: 'dashboard_macro' };
+  }
+
+  public getValue(fieldPath?: string): string {
+    const dashboard = getDashboardSceneFor(this._sceneObject);
+    switch (fieldPath) {
+      case 'uid':
+        return dashboard.state.uid || '';
+      case 'title':
+      case 'name':
+      case 'id':
+      default:
+        return dashboard.state.title;
+    }
+  }
+
+  public getValueText?(): string {
+    return '';
+  }
+}
+
+export function registerDashboardMacro() {
+  const unregister = sceneUtils.registerVariableMacro('__dashboard', DashboardMacro);
+
+  return () => unregister();
+}

public/app/features/dashboard-scene/serialization/transformSaveModelToScene.test.ts

@@ -113,9 +113,9 @@ describe('transformSaveModelToScene', () => {
 
       const scene = createDashboardSceneFromDashboardModel(oldModel);
 
-      expect(scene.state.$behaviors).toHaveLength(1);
+      expect(scene.state.$behaviors).toHaveLength(2);
-      expect(scene.state.$behaviors![0]).toBeInstanceOf(behaviors.CursorSync);
+      expect(scene.state.$behaviors![1]).toBeInstanceOf(behaviors.CursorSync);
-      expect((scene.state.$behaviors![0] as behaviors.CursorSync).state.sync).toEqual(DashboardCursorSync.Crosshair);
+      expect((scene.state.$behaviors![1] as behaviors.CursorSync).state.sync).toEqual(DashboardCursorSync.Crosshair);
     });
   });
 

public/app/features/dashboard-scene/serialization/transformSaveModelToScene.ts

@@ -32,6 +32,7 @@ import { DashboardDTO } from 'app/types';
 
 import { AlertStatesDataLayer } from '../scene/AlertStatesDataLayer';
 import { DashboardAnnotationsDataLayer } from '../scene/DashboardAnnotationsDataLayer';
+import { registerDashboardMacro } from '../scene/DashboardMacro';
 import { DashboardScene } from '../scene/DashboardScene';
 import { LibraryVizPanel } from '../scene/LibraryVizPanel';
 import { VizPanelLinks, VizPanelLinksMenu } from '../scene/PanelLinks';
@@ -249,6 +250,7 @@ export function createDashboardSceneFromDashboardModel(oldModel: DashboardModel)
     }),
     $variables: variables,
     $behaviors: [
+      registerDashboardMacro,
       new behaviors.CursorSync({
         sync: oldModel.graphTooltip,
       }),

public/app/features/dashboard-scene/serialization/transformSceneToSaveModel.test.ts

@@ -146,6 +146,15 @@ jest.mock('@grafana/runtime', () => ({
     },
   },
 }));
+
+jest.mock('@grafana/scenes', () => ({
+  ...jest.requireActual('@grafana/scenes'),
+  sceneUtils: {
+    ...jest.requireActual('@grafana/scenes').sceneUtils,
+    registerVariableMacro: jest.fn(),
+  },
+}));
+
 describe('transformSceneToSaveModel', () => {
   describe('Given a simple scene with variables', () => {
     it('Should transform back to persisted model', () => {