[Discover] Extract fetch observable initialization to separate function (#108831)

* Don't trigger autorefresh when there's no time picker
- because there's no UI for that

* Refactor and add test

* Add doc and test

* Refactor

* Remove index pattern without timefield filtering

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

src/plugins/discover/public/application/apps/main/services/use_saved_search.ts

@@ -6,15 +6,14 @@
  * Side Public License, v 1.
  */
 import { useCallback, useEffect, useMemo, useRef } from 'react';
-import { BehaviorSubject, merge, Subject } from 'rxjs';
-import { debounceTime, filter, tap } from 'rxjs/operators';
+import { BehaviorSubject, Subject } from 'rxjs';
 import { DiscoverServices } from '../../../../build_services';
 import { DiscoverSearchSessionManager } from './discover_search_session';
 import { SearchSource } from '../../../../../../data/common';
 import { GetStateReturn } from './discover_state';
 import { ElasticSearchHit } from '../../../doc_views/doc_views_types';
 import { RequestAdapter } from '../../../../../../inspector/public';
-import { AutoRefreshDoneFn } from '../../../../../../data/public';
+import type { AutoRefreshDoneFn } from '../../../../../../data/public';
 import { validateTimeRange } from '../utils/validate_time_range';
 import { Chart } from '../components/chart/point_series';
 import { useSingleton } from '../utils/use_singleton';
@@ -23,6 +22,7 @@ import { FetchStatus } from '../../../types';
 import { fetchAll } from '../utils/fetch_all';
 import { useBehaviorSubject } from '../utils/use_behavior_subject';
 import { sendResetMsg } from './use_saved_search_messages';
+import { getFetch$ } from '../utils/get_fetch_observable';
 
 export interface SavedSearchData {
   main$: DataMain$;
@@ -134,6 +134,7 @@ export const useSavedSearch = ({
    */
   const refs = useRef<{
     abortController?: AbortController;
+    autoRefreshDone?: AutoRefreshDoneFn;
   }>({});
 
   /**
@@ -145,29 +146,17 @@ export const useSavedSearch = ({
      * handler emitted by `timefilter.getAutoRefreshFetch$()`
      * to notify when data completed loading and to start a new autorefresh loop
      */
-    let autoRefreshDoneCb: AutoRefreshDoneFn | undefined;
-    const fetch$ = merge(
+    const setAutoRefreshDone = (fn: AutoRefreshDoneFn | undefined) => {
+      refs.current.autoRefreshDone = fn;
+    };
+    const fetch$ = getFetch$({
+      setAutoRefreshDone,
+      data,
+      main$,
       refetch$,
-      filterManager.getFetches$(),
-      timefilter.getFetch$(),
-      timefilter.getAutoRefreshFetch$().pipe(
-        tap((done) => {
-          autoRefreshDoneCb = done;
-        }),
-        filter(() => {
-          /**
-           * filter to prevent auto-refresh triggered fetch when
-           * loading is still ongoing
-           */
-          const currentFetchStatus = main$.getValue().fetchStatus;
-          return (
-            currentFetchStatus !== FetchStatus.LOADING && currentFetchStatus !== FetchStatus.PARTIAL
-          );
-        })
-      ),
-      data.query.queryString.getUpdates$(),
-      searchSessionManager.newSearchSessionIdFromURL$.pipe(filter((sessionId) => !!sessionId))
-    ).pipe(debounceTime(100));
+      searchSessionManager,
+      searchSource,
+    });
 
     const subscription = fetch$.subscribe((val) => {
       if (!validateTimeRange(timefilter.getTime(), services.toastNotifications)) {
@@ -190,8 +179,8 @@ export const useSavedSearch = ({
         }).subscribe({
           complete: () => {
             // if this function was set and is executed, another refresh fetch can be triggered
-            autoRefreshDoneCb?.();
-            autoRefreshDoneCb = undefined;
+            refs.current.autoRefreshDone?.();
+            refs.current.autoRefreshDone = undefined;
           },
         });
       } catch (error) {

src/plugins/discover/public/application/apps/main/utils/get_fetch_observable.ts

@@ -0,0 +1,61 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+import { merge } from 'rxjs';
+import { debounceTime, filter, tap } from 'rxjs/operators';
+
+import { FetchStatus } from '../../../types';
+import type {
+  AutoRefreshDoneFn,
+  DataPublicPluginStart,
+  SearchSource,
+} from '../../../../../../data/public';
+import { DataMain$, DataRefetch$ } from '../services/use_saved_search';
+import { DiscoverSearchSessionManager } from '../services/discover_search_session';
+
+/**
+ * This function returns an observable that's used to trigger data fetching
+ */
+export function getFetch$({
+  setAutoRefreshDone,
+  data,
+  main$,
+  refetch$,
+  searchSessionManager,
+}: {
+  setAutoRefreshDone: (val: AutoRefreshDoneFn | undefined) => void;
+  data: DataPublicPluginStart;
+  main$: DataMain$;
+  refetch$: DataRefetch$;
+  searchSessionManager: DiscoverSearchSessionManager;
+  searchSource: SearchSource;
+}) {
+  const { timefilter } = data.query.timefilter;
+  const { filterManager } = data.query;
+  return merge(
+    refetch$,
+    filterManager.getFetches$(),
+    timefilter.getFetch$(),
+    timefilter.getAutoRefreshFetch$().pipe(
+      tap((done) => {
+        setAutoRefreshDone(done);
+      }),
+      filter(() => {
+        const currentFetchStatus = main$.getValue().fetchStatus;
+        return (
+          /**
+           * filter to prevent auto-refresh triggered fetch when
+           * loading is still ongoing
+           */
+          currentFetchStatus !== FetchStatus.LOADING && currentFetchStatus !== FetchStatus.PARTIAL
+        );
+      })
+    ),
+    data.query.queryString.getUpdates$(),
+    searchSessionManager.newSearchSessionIdFromURL$.pipe(filter((sessionId) => !!sessionId))
+  ).pipe(debounceTime(100));
+}

src/plugins/discover/public/application/apps/main/utils/get_fetch_observeable.test.ts

@@ -0,0 +1,95 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+import { getFetch$ } from './get_fetch_observable';
+import { FetchStatus } from '../../../types';
+import { BehaviorSubject, Subject } from 'rxjs';
+import { DataPublicPluginStart } from '../../../../../../data/public';
+import { createSearchSessionMock } from '../../../../__mocks__/search_session';
+import { DataRefetch$ } from '../services/use_saved_search';
+import { savedSearchMock, savedSearchMockWithTimeField } from '../../../../__mocks__/saved_search';
+
+function createDataMock(
+  queryString$: Subject<unknown>,
+  filterManager$: Subject<unknown>,
+  timefilterFetch$: Subject<unknown>,
+  autoRefreshFetch$: Subject<unknown>
+) {
+  return {
+    query: {
+      queryString: {
+        getUpdates$: () => {
+          return queryString$;
+        },
+      },
+      filterManager: {
+        getFetches$: () => {
+          return filterManager$;
+        },
+      },
+      timefilter: {
+        timefilter: {
+          getFetch$: () => {
+            return timefilterFetch$;
+          },
+          getAutoRefreshFetch$: () => {
+            return autoRefreshFetch$;
+          },
+        },
+      },
+    },
+  } as unknown as DataPublicPluginStart;
+}
+
+describe('getFetchObservable', () => {
+  test('refetch$.next should trigger fetch$.next', async (done) => {
+    const searchSessionManagerMock = createSearchSessionMock();
+
+    const main$ = new BehaviorSubject({ fetchStatus: FetchStatus.UNINITIALIZED });
+    const refetch$: DataRefetch$ = new Subject();
+    const fetch$ = getFetch$({
+      setAutoRefreshDone: jest.fn(),
+      main$,
+      refetch$,
+      data: createDataMock(new Subject(), new Subject(), new Subject(), new Subject()),
+      searchSessionManager: searchSessionManagerMock.searchSessionManager,
+      searchSource: savedSearchMock.searchSource,
+    });
+
+    fetch$.subscribe(() => {
+      done();
+    });
+    refetch$.next();
+  });
+  test('getAutoRefreshFetch$ should trigger fetch$.next', async () => {
+    jest.useFakeTimers();
+    const searchSessionManagerMock = createSearchSessionMock();
+    const autoRefreshFetch$ = new Subject();
+
+    const main$ = new BehaviorSubject({ fetchStatus: FetchStatus.UNINITIALIZED });
+    const refetch$: DataRefetch$ = new Subject();
+    const dataMock = createDataMock(new Subject(), new Subject(), new Subject(), autoRefreshFetch$);
+    const setAutoRefreshDone = jest.fn();
+    const fetch$ = getFetch$({
+      setAutoRefreshDone,
+      main$,
+      refetch$,
+      data: dataMock,
+      searchSessionManager: searchSessionManagerMock.searchSessionManager,
+      searchSource: savedSearchMockWithTimeField.searchSource,
+    });
+
+    const fetchfnMock = jest.fn();
+    fetch$.subscribe(() => {
+      fetchfnMock();
+    });
+    autoRefreshFetch$.next(jest.fn());
+    jest.runAllTimers();
+    expect(fetchfnMock).toHaveBeenCalledTimes(1);
+    expect(setAutoRefreshDone).toHaveBeenCalled();
+  });
+});