From cd6809685f3fd296f5ef4f24b32c9d508938f02a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=A4ggmark?= <hugo.haggmark@grafana.com>
Date: Mon, 10 Feb 2020 06:29:52 +0100
Subject: [PATCH] BackendSrv: Returns correct error when a request is cancelled
 (#21992)

Fixes #21991
---
 public/app/core/services/backend_srv.ts   | 19 +++++-----
 public/app/core/specs/backend_srv.test.ts | 43 +++++++++--------------
 2 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/public/app/core/services/backend_srv.ts b/public/app/core/services/backend_srv.ts
index b7a92d9abbe..73f6e24f028 100644
--- a/public/app/core/services/backend_srv.ts
+++ b/public/app/core/services/backend_srv.ts
@@ -1,6 +1,6 @@
 import omitBy from 'lodash/omitBy';
 import { from, merge, MonoTypeOperatorFunction, Observable, Subject, throwError } from 'rxjs';
-import { catchError, filter, map, mergeMap, retryWhen, share, takeUntil, tap } from 'rxjs/operators';
+import { catchError, filter, map, mergeMap, retryWhen, share, takeUntil, tap, throwIfEmpty } from 'rxjs/operators';
 import { fromFetch } from 'rxjs/fetch';
 import { BackendSrv as BackendService, BackendSrvRequest } from '@grafana/runtime';
 import { AppEvents } from '@grafana/data';
@@ -214,13 +214,6 @@ export class BackendSrv implements BackendService {
     return merge(successStream, failureStream)
       .pipe(
         catchError((err: ErrorResponse) => {
-          if (err.status === this.HTTP_REQUEST_CANCELED) {
-            return throwError({
-              err,
-              cancelled: true,
-            });
-          }
-
           // populate error obj on Internal Error
           if (typeof err.data === 'string' && err.status === 500) {
             err.data = {
@@ -253,7 +246,15 @@ export class BackendSrv implements BackendService {
               return cancelRequest;
             })
           )
-        )
+        ),
+        // when a request is cancelled by takeUntil it will complete without emitting anything
+        // throwIfEmpty will then throw an error with cancelled set to true
+        throwIfEmpty(() => ({
+          cancelled: true,
+          status: this.HTTP_REQUEST_CANCELED,
+          statusText: 'Request was aborted',
+          request: { url: parseUrlFromOptions(options), ...parseInitFromOptions(options) },
+        }))
       )
       .toPromise();
   }
diff --git a/public/app/core/specs/backend_srv.test.ts b/public/app/core/specs/backend_srv.test.ts
index 7c22c0021f1..508556ffd17 100644
--- a/public/app/core/specs/backend_srv.test.ts
+++ b/public/app/core/specs/backend_srv.test.ts
@@ -416,8 +416,22 @@ describe('backendSrv', () => {
           },
         });
 
-        const slowResponse = await slowRequest;
-        expect(slowResponse).toEqual(undefined);
+        await slowRequest.catch(error => {
+          expect(error).toEqual({
+            cancelled: true,
+            status: -1,
+            statusText: 'Request was aborted',
+            request: {
+              url,
+              method: 'GET',
+              body: undefined,
+              headers: {
+                'Content-Type': 'application/json',
+                Accept: 'application/json, text/plain, */*',
+              },
+            },
+          });
+        });
         expect(unsubscribe).toHaveBeenCalledTimes(1);
       });
     });
@@ -480,31 +494,6 @@ describe('backendSrv', () => {
       });
     });
 
-    describe('when making a HTTP_REQUEST_CANCELED call', () => {
-      it('then it should throw cancelled error', async () => {
-        const { backendSrv, appEventsMock, logoutMock, expectDataSourceRequestCallChain } = getTestContext({
-          ok: false,
-          status: -1,
-          statusText: 'HTTP_REQUEST_CANCELED',
-          data: { message: 'HTTP_REQUEST_CANCELED' },
-        });
-        const url = '/api/dashboard/';
-        await backendSrv.datasourceRequest({ url, method: 'GET' }).catch(error => {
-          expect(error).toEqual({
-            err: {
-              status: -1,
-              statusText: 'HTTP_REQUEST_CANCELED',
-              data: { message: 'HTTP_REQUEST_CANCELED' },
-            },
-            cancelled: true,
-          });
-          expect(appEventsMock.emit).not.toHaveBeenCalled();
-          expect(logoutMock).not.toHaveBeenCalled();
-          expectDataSourceRequestCallChain({ url, method: 'GET' });
-        });
-      });
-    });
-
     describe('when making an Internal Error call', () => {
       it('then it should throw cancelled error', async () => {
         const { backendSrv, appEventsMock, logoutMock, expectDataSourceRequestCallChain } = getTestContext({