From 20b07fae6f190abe1a433e18364b74682aad0644 Mon Sep 17 00:00:00 2001
From: Sven Grossmann <Svennergr@gmail.com>
Date: Fri, 9 Sep 2022 12:04:51 +0200
Subject: [PATCH] fix bug in loki's adhoc filters (#54920)

---
 .../plugins/datasource/loki/datasource.test.ts   | 16 ++++++++++++++++
 public/app/plugins/datasource/loki/datasource.ts |  5 +++--
 .../querybuilder/shared/parsingUtils.ts          |  2 +-
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/public/app/plugins/datasource/loki/datasource.test.ts b/public/app/plugins/datasource/loki/datasource.test.ts
index b7efeb0004c..11da36c2698 100644
--- a/public/app/plugins/datasource/loki/datasource.test.ts
+++ b/public/app/plugins/datasource/loki/datasource.test.ts
@@ -639,6 +639,22 @@ describe('LokiDatasource', () => {
         it('then the correct label should be added for metrics query', () => {
           assertAdHocFilters('rate({bar="baz"}[5m])', 'rate({bar="baz", job="grafana"}[5m])', ds);
         });
+
+        it('then the correct label should be added for metrics query and variable', () => {
+          assertAdHocFilters('rate({bar="baz"}[$__interval])', 'rate({bar="baz", job="grafana"}[$__interval])', ds);
+        });
+
+        it('then the correct label should be added for logs query with empty selector', () => {
+          assertAdHocFilters('{}', '{job="grafana"}', ds);
+        });
+
+        it('then the correct label should be added for metrics query with empty selector', () => {
+          assertAdHocFilters('rate({}[5m])', 'rate({job="grafana"}[5m])', ds);
+        });
+
+        it('then the correct label should be added for metrics query with empty selector and variable', () => {
+          assertAdHocFilters('rate({}[$__interval])', 'rate({job="grafana"}[$__interval])', ds);
+        });
       });
       describe('and query has parser', () => {
         it('then the correct label should be added for logs query', () => {
diff --git a/public/app/plugins/datasource/loki/datasource.ts b/public/app/plugins/datasource/loki/datasource.ts
index 7ba38064dde..761de171144 100644
--- a/public/app/plugins/datasource/loki/datasource.ts
+++ b/public/app/plugins/datasource/loki/datasource.ts
@@ -43,6 +43,7 @@ import { getTemplateSrv, TemplateSrv } from 'app/features/templating/template_sr
 
 import { serializeParams } from '../../../core/utils/fetch';
 import { renderLegendFormat } from '../prometheus/legend';
+import { replaceVariables, returnVariables } from '../prometheus/querybuilder/shared/parsingUtils';
 
 import LanguageProvider from './LanguageProvider';
 import { transformBackendResult } from './backendResultTransformer';
@@ -698,14 +699,14 @@ export class LokiDatasource
 
   addAdHocFilters(queryExpr: string) {
     const adhocFilters = this.templateSrv.getAdhocFilters(this.name);
-    let expr = queryExpr;
+    let expr = replaceVariables(queryExpr);
 
     expr = adhocFilters.reduce((acc: string, filter: { key: string; operator: string; value: string }) => {
       const { key, operator, value } = filter;
       return this.addLabelToQuery(acc, key, operator, value);
     }, expr);
 
-    return expr;
+    return returnVariables(expr);
   }
 
   addLabelToQuery(queryExpr: string, key: string, operator: string, value: string) {
diff --git a/public/app/plugins/datasource/prometheus/querybuilder/shared/parsingUtils.ts b/public/app/plugins/datasource/prometheus/querybuilder/shared/parsingUtils.ts
index 9d939ebc5c0..21d0d1e268e 100644
--- a/public/app/plugins/datasource/prometheus/querybuilder/shared/parsingUtils.ts
+++ b/public/app/plugins/datasource/prometheus/querybuilder/shared/parsingUtils.ts
@@ -65,7 +65,7 @@ const varTypeFunc = [
  * Get back the text with variables in their original format.
  * @param expr
  */
-function returnVariables(expr: string) {
+export function returnVariables(expr: string) {
   return expr.replace(/__V_(\d)__(.+?)__V__(?:__F__(\w+)__F__)?/g, (match, type, v, f) => {
     return varTypeFunc[parseInt(type, 10)](v, f);
   });