Graphite: Display an error message when finding metrics fails

public/app/plugins/datasource/graphite/query_ctrl.ts

@@ -24,8 +24,9 @@ export class GraphiteQueryCtrl extends QueryCtrl {
   supportsTags: boolean;
   paused: boolean;
 
-  // to avoid error flooding, it's shown only once per session
+  // to avoid error flooding, these errors are shown only once per session
   private _tagsAutoCompleteErrorShown = false;
+  private _metricAutoCompleteErrorShown = false;
 
   /** @ngInject */
   constructor(
@@ -110,7 +111,7 @@ export class GraphiteQueryCtrl extends QueryCtrl {
         }
       })
       .catch((err: any) => {
-        dispatch(notifyApp(createErrorNotification('Error', err)));
+        this.handleMetricsAutoCompleteError(err);
       });
   }
 
@@ -183,6 +184,7 @@ export class GraphiteQueryCtrl extends QueryCtrl {
         }
       })
       .catch((err: any): any[] => {
+        this.handleMetricsAutoCompleteError(err);
         return [];
       });
   }
@@ -437,6 +439,14 @@ export class GraphiteQueryCtrl extends QueryCtrl {
       dispatch(notifyApp(createErrorNotification(`Fetching tags failed: ${error.message}.`)));
     }
   }
+
+  private handleMetricsAutoCompleteError(error: Error): void {
+    console.log(error);
+    if (!this._metricAutoCompleteErrorShown) {
+      this._metricAutoCompleteErrorShown = true;
+      dispatch(notifyApp(createErrorNotification(`Fetching metrics failed: ${error.message}.`)));
+    }
+  }
 }
 
 function mapToDropdownOptions(results: any[]) {

public/app/plugins/datasource/graphite/specs/query_ctrl.test.ts

@@ -193,10 +193,61 @@ describe('GraphiteQueryCtrl', () => {
     });
   });
 
+  describe('when autocomplete for metric names is not available', () => {
+    silenceConsoleOutput();
+    beforeEach(() => {
+      ctx.ctrl.datasource.getTagsAutoComplete = jest.fn().mockReturnValue(Promise.resolve([]));
+      ctx.ctrl.datasource.metricFindQuery = jest.fn().mockReturnValue(
+        new Promise(() => {
+          throw new Error();
+        })
+      );
+    });
+
+    it('getAltSegments should handle autocomplete errors', async () => {
+      await expect(async () => {
+        await ctx.ctrl.getAltSegments(0, 'any');
+        expect(mockDispatch).toBeCalledWith(
+          expect.objectContaining({
+            type: 'appNotifications/notifyApp',
+          })
+        );
+      }).not.toThrow();
+    });
+
+    it('getAltSegments should display the error message only once', async () => {
+      await ctx.ctrl.getAltSegments(0, 'any');
+      expect(mockDispatch.mock.calls.length).toBe(1);
+
+      await ctx.ctrl.getAltSegments(0, 'any');
+      expect(mockDispatch.mock.calls.length).toBe(1);
+    });
+
+    it('checkOtherSegments should handle autocomplete errors', async () => {
+      await expect(async () => {
+        await ctx.ctrl.checkOtherSegments(1, false);
+        expect(mockDispatch).toBeCalledWith(
+          expect.objectContaining({
+            type: 'appNotifications/notifyApp',
+          })
+        );
+      }).not.toThrow();
+    });
+
+    it('checkOtherSegments should display the error message only once', async () => {
+      await ctx.ctrl.checkOtherSegments(1, false);
+      expect(mockDispatch.mock.calls.length).toBe(1);
+
+      await ctx.ctrl.checkOtherSegments(1, false);
+      expect(mockDispatch.mock.calls.length).toBe(1);
+    });
+  });
+
   describe('when autocomplete for tags is not available', () => {
     silenceConsoleOutput();
     beforeEach(() => {
-      ctx.ctrl.datasource.getTagsAutoComplete.mockReturnValue(
+      ctx.datasource.metricFindQuery = jest.fn().mockReturnValue(Promise.resolve([]));
+      ctx.datasource.getTagsAutoComplete = jest.fn().mockReturnValue(
         new Promise(() => {
           throw new Error();
         })