Add Throughput chart error handling

The throughput chart currently does not display errors on
the frontend.

This MR introduces a nice FE error message display.

ee/app/assets/javascripts/analytics/merge_request_analytics/components/throughput_chart.vue

@@ -3,7 +3,7 @@ import { GlAreaChart } from '@gitlab/ui/dist/charts';
 import { GlAlert, GlLoadingIcon } from '@gitlab/ui';
 import { getDateInPast } from '~/lib/utils/datetime_utility';
 import throughputChartQueryBuilder from '../graphql/throughput_chart_query_builder';
-import { DEFAULT_NUMBER_OF_DAYS, THROUGHPUT_STRINGS } from '../constants';
+import { DEFAULT_NUMBER_OF_DAYS, THROUGHPUT_CHART_STRINGS } from '../constants';
 
 export default {
   name: 'ThroughputChart',
@@ -18,6 +18,7 @@ export default {
       throughputChartData: [],
       startDate: getDateInPast(new Date(), DEFAULT_NUMBER_OF_DAYS),
       endDate: new Date(),
+      hasError: false,
     };
   },
   apollo: {
@@ -30,13 +31,16 @@ export default {
           fullPath: this.fullPath,
         };
       },
+      error() {
+        this.hasError = true;
+      },
     },
   },
   computed: {
     chartOptions() {
       return {
         xAxis: {
-          name: THROUGHPUT_STRINGS.X_AXIS_TITLE,
+          name: THROUGHPUT_CHART_STRINGS.X_AXIS_TITLE,
           type: 'category',
           axisLabel: {
             formatter: value => {
@@ -45,33 +49,42 @@ export default {
           },
         },
         yAxis: {
-          name: THROUGHPUT_STRINGS.Y_AXIS_TITLE,
+          name: THROUGHPUT_CHART_STRINGS.Y_AXIS_TITLE,
         },
       };
     },
     formattedThroughputChartData() {
+      if (!this.throughputChartData) return [];
+
       const data = Object.keys(this.throughputChartData)
         .slice(0, -1) // Remove the __typeName key
         .map(value => [value, this.throughputChartData[value].count]);
 
       return [
         {
-          name: THROUGHPUT_STRINGS.Y_AXIS_TITLE,
+          name: THROUGHPUT_CHART_STRINGS.Y_AXIS_TITLE,
           data,
         },
       ];
     },
     chartDataLoading() {
-      return this.$apollo.queries.throughputChartData.loading;
+      return !this.hasError && this.$apollo.queries.throughputChartData.loading;
     },
     chartDataAvailable() {
-      return this.formattedThroughputChartData[0].data.length;
+      return this.formattedThroughputChartData[0]?.data.length;
+    },
+    alertDetails() {
+      return {
+        class: this.hasError ? 'danger' : 'info',
+        message: this.hasError
+          ? THROUGHPUT_CHART_STRINGS.ERROR_FETCHING_DATA
+          : THROUGHPUT_CHART_STRINGS.NO_DATA,
+      };
     },
   },
   strings: {
-    chartTitle: THROUGHPUT_STRINGS.CHART_TITLE,
-    chartDescription: THROUGHPUT_STRINGS.CHART_DESCRIPTION,
-    noData: THROUGHPUT_STRINGS.NO_DATA,
+    chartTitle: THROUGHPUT_CHART_STRINGS.CHART_TITLE,
+    chartDescription: THROUGHPUT_CHART_STRINGS.CHART_DESCRIPTION,
   },
 };
 </script>
@@ -87,6 +100,8 @@ export default {
       :data="formattedThroughputChartData"
       :option="chartOptions"
     />
-    <gl-alert v-else :dismissible="false" class="gl-mt-4">{{ $options.strings.noData }}</gl-alert>
+    <gl-alert v-else :variant="alertDetails.class" :dismissible="false" class="gl-mt-4">{{
+      alertDetails.message
+    }}</gl-alert>
   </div>
 </template>

ee/app/assets/javascripts/analytics/merge_request_analytics/constants.js

 import { __ } from '~/locale';
 
 export const DEFAULT_NUMBER_OF_DAYS = 365;
-export const THROUGHPUT_STRINGS = {
+export const THROUGHPUT_CHART_STRINGS = {
   CHART_TITLE: __('Throughput'),
   Y_AXIS_TITLE: __('Merge Requests merged'),
   X_AXIS_TITLE: __('Month'),
   CHART_DESCRIPTION: __('The number of merge requests merged by month.'),
-  NO_DATA: __('There is no data available.'),
+  NO_DATA: __('There is no chart data available.'),
+  ERROR_FETCHING_DATA: __('There was an error while fetching the chart data.'),
 };

ee/spec/frontend/analytics/merge_request_analytics/components/throughput_chart_spec.js

@@ -2,7 +2,7 @@ import { shallowMount } from '@vue/test-utils';
 import { GlAlert, GlLoadingIcon } from '@gitlab/ui';
 import { GlAreaChart } from '@gitlab/ui/dist/charts';
 import ThroughputChart from 'ee/analytics/merge_request_analytics/components/throughput_chart.vue';
-import { THROUGHPUT_STRINGS } from 'ee/analytics/merge_request_analytics/constants';
+import { THROUGHPUT_CHART_STRINGS } from 'ee/analytics/merge_request_analytics/constants';
 import { throughputChartData } from '../mock_data';
 
 const fullPath = 'gitlab-org/gitlab';
@@ -48,20 +48,20 @@ describe('ThroughputChart', () => {
     it('displays the chart title', () => {
       const chartTitle = wrapper.find('[data-testid="chartTitle"').text();
 
-      expect(chartTitle).toBe(THROUGHPUT_STRINGS.CHART_TITLE);
+      expect(chartTitle).toBe(THROUGHPUT_CHART_STRINGS.CHART_TITLE);
     });
 
     it('displays the chart description', () => {
       const chartDescription = wrapper.find('[data-testid="chartDescription"').text();
 
-      expect(chartDescription).toBe(THROUGHPUT_STRINGS.CHART_DESCRIPTION);
+      expect(chartDescription).toBe(THROUGHPUT_CHART_STRINGS.CHART_DESCRIPTION);
     });
 
     it('displays an empty state message when there is no data', () => {
       const alert = wrapper.find(GlAlert);
 
       expect(alert.exists()).toBe(true);
-      expect(alert.text()).toBe(THROUGHPUT_STRINGS.NO_DATA);
+      expect(alert.text()).toBe(THROUGHPUT_CHART_STRINGS.NO_DATA);
     });
 
     it('does not display a loading icon', () => {
@@ -86,7 +86,7 @@ describe('ThroughputChart', () => {
       displaysComponent(GlAreaChart, false);
     });
 
-    it('does not display the no data message', () => {
+    it('does not display a no data message', () => {
       displaysComponent(GlAlert, false);
     });
   });
@@ -104,8 +104,29 @@ describe('ThroughputChart', () => {
       displaysComponent(GlLoadingIcon, false);
     });
 
-    it('does not display the no data message', () => {
+    it('does not display a no data message', () => {
       displaysComponent(GlAlert, false);
     });
   });
+
+  describe('with errors', () => {
+    beforeEach(() => {
+      createComponent({ data: { hasError: true } });
+    });
+
+    it('does not display the chart', () => {
+      displaysComponent(GlAreaChart, false);
+    });
+
+    it('does not display a loading icon', () => {
+      displaysComponent(GlLoadingIcon, false);
+    });
+
+    it('displays an error message', () => {
+      const alert = wrapper.find(GlAlert);
+
+      expect(alert.exists()).toBe(true);
+      expect(alert.text()).toBe(THROUGHPUT_CHART_STRINGS.ERROR_FETCHING_DATA);
+    });
+  });
 });

locale/gitlab.pot

@@ -24443,7 +24443,7 @@ msgstr ""
 msgid "There is already a repository with that name on disk"
 msgstr ""
 
-msgid "There is no data available."
+msgid "There is no chart data available."
 msgstr ""
 
 msgid "There is no data available. Please change your selection."
@@ -24611,6 +24611,9 @@ msgstr ""
 msgid "There was an error when unsubscribing from this label."
 msgstr ""
 
+msgid "There was an error while fetching the chart data."
+msgstr ""
+
 msgid "There was an error while fetching value stream analytics data."
 msgstr ""