Alerting: update response text assertion (#43291)

public/app/features/alerting/unified/api/ruler.ts

@@ -1,10 +1,15 @@
 import { lastValueFrom } from 'rxjs';
-import { getBackendSrv } from '@grafana/runtime';
+import { FetchResponse, getBackendSrv } from '@grafana/runtime';
 
 import { PostableRulerRuleGroupDTO, RulerRuleGroupDTO, RulerRulesConfigDTO } from 'app/types/unified-alerting-dto';
 import { getDatasourceAPIId, GRAFANA_RULES_SOURCE_NAME } from '../utils/datasource';
 import { RULER_NOT_SUPPORTED_MSG } from '../utils/constants';
 
+interface ErrorResponseMessage {
+  message?: string;
+  error?: string;
+}
+
 // upsert a rule group. use this to update rules
 export async function setRulerRuleGroup(
   dataSourceName: string,
@@ -97,28 +102,47 @@ async function rulerGetRequest<T>(url: string, empty: T, params?: Record<string,
       })
     );
     return response.data;
-  } catch (e) {
+  } catch (error) {
-    if (e?.status === 404) {
+    if (!isResponseError(error)) {
-      if (e?.data?.message?.includes('group does not exist') || e?.data?.message?.includes('no rule groups found')) {
+      throw error;
+    }
+
+    const notFoundError = error.status === 404;
+    const rulerNotSupported =
+      error.status === 500 &&
+      error.data.error?.includes('unexpected content type from upstream. expected YAML, got text/html');
+
+    if (notFoundError) {
+      // the endpoint will return 404 but confirm that it's a Cortex endpoint
+      if (isCortexErrorResponse(error)) {
         return empty;
       }
+      // any other 404 should throw an exception
       throw new Error('404 from rules config endpoint. Perhaps ruler API is not enabled?');
-    } else if (
+    } else if (rulerNotSupported) {
-      e?.status === 500 &&
+      // assert if the endoint is not supported at all
-      e?.data?.message?.includes('unexpected content type from upstream. expected YAML, got text/html')
-    ) {
       throw {
-        ...e,
+        ...error,
         data: {
-          ...e?.data,
+          ...error.data,
           message: RULER_NOT_SUPPORTED_MSG,
         },
       };
     }
-    throw e;
+    throw error;
   }
 }
 
+function isResponseError(error: unknown): error is FetchResponse<ErrorResponseMessage> {
+  const hasErrorMessage = (error as FetchResponse<ErrorResponseMessage>).data != null;
+  const hasErrorCode = Number.isFinite((error as FetchResponse<ErrorResponseMessage>).status);
+  return hasErrorCode && hasErrorMessage;
+}
+
+function isCortexErrorResponse(error: FetchResponse<ErrorResponseMessage>) {
+  return error.data.error?.includes('group does not exist') || error.data.error?.includes('no rule groups found');
+}
+
 export async function deleteNamespace(dataSourceName: string, namespace: string): Promise<void> {
   await lastValueFrom(
     getBackendSrv().fetch<unknown>({