loki: do not use backend-mode when keepCookies is used (#49222)

public/app/plugins/datasource/loki/datasource.ts

@@ -105,6 +105,7 @@ export class LokiDatasource
   private streams = new LiveStreams();
   languageProvider: LanguageProvider;
   maxLines: number;
+  useBackendMode: boolean;
 
   constructor(
     private instanceSettings: DataSourceInstanceSettings<LokiOptions>,
@@ -116,6 +117,9 @@ export class LokiDatasource
     this.languageProvider = new LanguageProvider(this);
     const settingsData = instanceSettings.jsonData || {};
     this.maxLines = parseInt(settingsData.maxLines ?? '0', 10) || DEFAULT_MAX_LINES;
+    const keepCookiesUsed = (settingsData.keepCookies ?? []).length > 0;
+    // only use backend-mode when keep-cookies is not used
+    this.useBackendMode = !keepCookiesUsed && (config.featureToggles.lokiBackendMode ?? false);
   }
 
   _request(apiUrl: string, data?: any, options?: Partial<BackendSrvRequest>): Observable<Record<string, any>> {
@@ -168,7 +172,7 @@ export class LokiDatasource
       ...this.getRangeScopedVars(request.range),
     };
 
-    if (config.featureToggles.lokiBackendMode) {
+    if (this.useBackendMode) {
       // we "fix" the loki queries to have `.queryType` and not have `.instant` and `.range`
       const fixedRequest = {
         ...request,

public/app/plugins/datasource/loki/types.ts

@@ -57,6 +57,7 @@ export interface LokiOptions extends DataSourceJsonData {
   maxLines?: string;
   derivedFields?: DerivedFieldConfig[];
   alertmanager?: string;
+  keepCookies?: string[];
 }
 
 export interface LokiStats {