fix: parse custom and query variables using our special function (#760)

Author: simPod

src/DataSource.ts

@@ -29,6 +29,8 @@ import {
 import { VariableSupport } from './variable/VariableSupport';
 import { doFetch } from './doFetch';
 import { MetricFindQuery } from './MetricFindQuery';
+import { match, P } from 'ts-pattern';
+import { valueFromVariableWithMultiSupport } from './variable/valueFromVariableWithMultiSupport';
 
 export class DataSource extends DataSourceApi<GrafanaQuery, GenericOptions> {
   url: string;
@@ -305,7 +307,12 @@ export class DataSource extends DataSourceApi<GrafanaQuery, GenericOptions> {
         return;
       }
 
-      const value = getTemplateSrv().replace('$' + variable.name, scopedVars, 'json');
+      const value = match(variable)
+        .with({ type: P.union('custom', 'query') }, (v) => valueFromVariableWithMultiSupport(v))
+        .with({ type: P.union('constant', 'datasource', 'groupby', 'interval', 'snapshot', 'textbox') }, (v) =>
+          getTemplateSrv().replace('$' + variable.name, scopedVars, 'json')
+        )
+        .exhaustive();
 
       variableOptions[variable.name] = {
         text: variable.current.text,

src/variable/valueFromVariableWithMultiSupport.ts

@@ -0,0 +1,23 @@
+import { VariableWithMultiSupport } from '@grafana/data';
+import { isEqual } from 'lodash';
+
+export const valueFromVariableWithMultiSupport = (variable: VariableWithMultiSupport) => {
+  let variableValue = variable.current.value;
+  if (variableValue === '$__all' || isEqual(variableValue, ['$__all'])) {
+    if (variable.allValue === null || variable.allValue === '' || variable.allValue === undefined) {
+      variableValue = variable.options.slice(1).map((variableOption) => {
+        if (typeof variableOption.value !== 'string') {
+          const error = new Error('Variable option value is not a string');
+          console.error(error.message, variableOption, variable);
+
+          throw error;
+        }
+        return variableOption.value;
+      });
+    } else {
+      variableValue = variable.allValue;
+    }
+  }
+
+  return variableValue;
+};