From 0caeaaafe3c37230b3e2b477a317d2416aaf57b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Farkas?= <gabor.farkas@gmail.com>
Date: Sat, 21 May 2022 16:46:39 +0200
Subject: [PATCH] loki: add back frontend-mode metadata queries (#49297)

---
 public/app/plugins/datasource/loki/datasource.test.ts |  6 ++----
 public/app/plugins/datasource/loki/datasource.ts      | 11 +++++++++--
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/public/app/plugins/datasource/loki/datasource.test.ts b/public/app/plugins/datasource/loki/datasource.test.ts
index c792e24a564..1919f610ee2 100644
--- a/public/app/plugins/datasource/loki/datasource.test.ts
+++ b/public/app/plugins/datasource/loki/datasource.test.ts
@@ -1002,7 +1002,7 @@ describe('LokiDatasource', () => {
   describe('importing queries', () => {
     it('keeps all labels when no labels are loaded', async () => {
       const ds = createLokiDSForTests();
-      ds.getResource = () => Promise.resolve({ data: [] });
+      fetchMock.mockImplementation(() => of(createFetchResponse({ data: [] })));
       const queries = await ds.importFromAbstractQueries([
         {
           refId: 'A',
@@ -1017,9 +1017,7 @@ describe('LokiDatasource', () => {
 
     it('filters out non existing labels', async () => {
       const ds = createLokiDSForTests();
-      ds.getResource = () => {
-        return Promise.resolve({ data: ['foo'] });
-      };
+      fetchMock.mockImplementation(() => of(createFetchResponse({ data: ['foo'] })));
       const queries = await ds.importFromAbstractQueries([
         {
           refId: 'A',
diff --git a/public/app/plugins/datasource/loki/datasource.ts b/public/app/plugins/datasource/loki/datasource.ts
index ded5e3619dc..828b3be499b 100644
--- a/public/app/plugins/datasource/loki/datasource.ts
+++ b/public/app/plugins/datasource/loki/datasource.ts
@@ -467,8 +467,15 @@ export class LokiDatasource
     if (url.startsWith('/')) {
       throw new Error(`invalid metadata request url: ${url}`);
     }
-    const res = await this.getResource(url, params);
-    return res.data || [];
+
+    if (this.useBackendMode) {
+      const res = await this.getResource(url, params);
+      return res.data || [];
+    } else {
+      const lokiURL = `${LOKI_ENDPOINT}/${url}`;
+      const res = await lastValueFrom(this._request(lokiURL, params, { hideFromInspector: true }));
+      return res.data.data || [];
+    }
   }
 
   async metricFindQuery(query: string) {