Variables: Add datasource variable support (#1006)

packages/scenes/src/variables/variants/query/createQueryVariableRunner.ts

@@ -10,7 +10,12 @@ import {
 } from '@grafana/data';
 import { getRunRequest } from '@grafana/runtime';
 
-import { hasCustomVariableSupport, hasLegacyVariableSupport, hasStandardVariableSupport } from './guards';
+import {
+  hasCustomVariableSupport,
+  hasDataSourceVariableSupport,
+  hasLegacyVariableSupport,
+  hasStandardVariableSupport,
+} from './guards';
 
 import { QueryVariable } from './QueryVariable';
 import { DataQuery } from '@grafana/schema';
@@ -111,6 +116,31 @@ class CustomQueryRunner implements QueryRunner {
   }
 }
 
+const variableDummyRefId = 'variable-query';
+class DatasourceQueryRunner implements QueryRunner {
+  public constructor(private datasource: DataSourceApi, private _runRequest = getRunRequest()) {}
+
+  public getTarget(variable: QueryVariable) {
+    if (hasDataSourceVariableSupport(this.datasource)) {
+      if (typeof variable.state.query === 'string') {
+        return variable.state.query;
+      }
+
+      return { ...variable.state.query, refId: variable.state.query.refId ?? variableDummyRefId };
+    }
+
+    throw new Error("Couldn't create a target with supplied arguments.");
+  }
+
+  public runRequest(_: RunnerArgs, request: DataQueryRequest) {
+    if (!hasDataSourceVariableSupport(this.datasource)) {
+      return getEmptyMetricFindValueObservable();
+    }
+
+    return this._runRequest(this.datasource, request, this.datasource.query);
+  }
+}
+
 function getEmptyMetricFindValueObservable(): Observable<PanelData> {
   return of({ state: LoadingState.Done, series: [], timeRange: getDefaultTimeRange() });
 }
@@ -128,6 +158,10 @@ function createQueryVariableRunnerFactory(datasource: DataSourceApi): QueryRunne
     return new CustomQueryRunner(datasource);
   }
 
+  if (hasDataSourceVariableSupport(datasource)) {
+    return new DatasourceQueryRunner(datasource);
+  }
+
   throw new Error(`Couldn't create a query runner for datasource ${datasource.type}`);
 }
 

packages/scenes/src/variables/variants/query/guards.ts

@@ -110,3 +110,16 @@ export const hasCustomVariableSupport = <
     Boolean(variableSupport.editor)
   );
 };
+
+export const hasDataSourceVariableSupport = <
+  TQuery extends DataQuery = DataQuery,
+  TOptions extends DataSourceJsonData = DataSourceJsonData
+>(
+  datasource: DataSourceApi<TQuery, TOptions>
+): datasource is DataSourceWithCustomVariableSupport<TQuery, TOptions> => {
+  if (!datasource.variables) {
+    return false;
+  }
+
+  return datasource.variables.getType() === VariableSupportType.Datasource;
+};