Elasticsearch: revert to isoWeek when resolving weekly indices (#31709)

* Elasticsearch: revert to isoWeek when resolving weekly indices

* Add type assertion explainer

packages/grafana-data/src/datetime/moment_wrapper.ts

@@ -1,6 +1,6 @@
 import { TimeZone } from '../types/time';
 /* eslint-disable id-blacklist, no-restricted-imports, @typescript-eslint/ban-types */
-import moment, { Moment, MomentInput, DurationInputArg1 } from 'moment';
+import moment, { Moment, MomentInput, DurationInputArg1, DurationInputArg2 } from 'moment';
 export interface DateTimeBuiltinFormat {
   __momentBuiltinFormatBrand: any;
 }
@@ -17,6 +17,7 @@ export type DurationUnit =
   | 'M'
   | 'week'
   | 'weeks'
+  | 'isoWeek'
   | 'w'
   | 'day'
   | 'days'
@@ -96,7 +97,8 @@ export const toUtc = (input?: DateTimeInput, formatInput?: FormatInput): DateTim
 };
 
 export const toDuration = (input?: DurationInput, unit?: DurationUnit): DateTimeDuration => {
-  return moment.duration(input as DurationInputArg1, unit) as DateTimeDuration;
+  // moment built-in types are a bit flaky, for example `isoWeek` is not in the type definition but it's present in the js source.
+  return moment.duration(input as DurationInputArg1, unit as DurationInputArg2) as DateTimeDuration;
 };
 
 export const dateTime = (input?: DateTimeInput, formatInput?: FormatInput): DateTime => {

public/app/plugins/datasource/elasticsearch/index_pattern.ts

@@ -12,7 +12,7 @@ type IntervalMap = Record<
 const intervalMap: IntervalMap = {
   Hourly: { startOf: 'hour', amount: 'hours' },
   Daily: { startOf: 'day', amount: 'days' },
-  Weekly: { startOf: 'week', amount: 'weeks' },
+  Weekly: { startOf: 'isoWeek', amount: 'weeks' },
   Monthly: { startOf: 'month', amount: 'months' },
   Yearly: { startOf: 'year', amount: 'years' },
 };

public/app/plugins/datasource/elasticsearch/specs/index_pattern.test.ts

@@ -55,6 +55,20 @@ describe('IndexPattern', () => {
         expect(pattern.getIndexList(from, to)).toEqual(expected);
       });
     });
+
+    describe('weekly', () => {
+      it('should return correct index list', () => {
+        const pattern = new IndexPattern('[asd-]YYYY.WW', 'Weekly');
+        // Sunday, February 21, 2021 1:00:00 AM
+        const from = dateTime(new Date(1613869200000));
+        // Friday, March 5, 2021 1:00:00 AM
+        const to = dateTime(new Date(1614906000000));
+
+        const expected = ['asd-2021.07', 'asd-2021.08', 'asd-2021.09'];
+
+        expect(pattern.getIndexList(from, to)).toEqual(expected);
+      });
+    });
   });
 
   describe('when getting index list from single date', () => {