[Fleet] Fix agent action observable for long polling (#81376)

Author: nchaulet

x-pack/plugins/ingest_manager/server/services/agents/actions.ts

@@ -247,11 +247,16 @@ export async function getNewActionsSince(
         nodeTypes.literal.buildNode(false),
       ])
     ),
+    nodeTypes.function.buildNodeWithArgumentNodes('is', [
+      nodeTypes.literal.buildNode(`${AGENT_ACTION_SAVED_OBJECT_TYPE}.attributes.agent_id`),
+      nodeTypes.wildcard.buildNode(nodeTypes.wildcard.wildcardSymbol),
+      nodeTypes.literal.buildNode(false),
+    ]),
     nodeTypes.function.buildNode(
       'range',
       `${AGENT_ACTION_SAVED_OBJECT_TYPE}.attributes.created_at`,
       {
-        gte: timestamp,
+        gt: timestamp,
       }
     ),
   ]);

x-pack/plugins/ingest_manager/server/services/agents/checkin/state_new_actions.test.ts

@@ -4,11 +4,19 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 import { savedObjectsClientMock } from 'src/core/server/mocks';
-import { createAgentActionFromPolicyAction } from './state_new_actions';
-import { OutputType, Agent, AgentPolicyAction } from '../../../types';
+import { take } from 'rxjs/operators';
+import {
+  createAgentActionFromPolicyAction,
+  createNewActionsSharedObservable,
+} from './state_new_actions';
+import { getNewActionsSince } from '../actions';
+import { OutputType, Agent, AgentAction, AgentPolicyAction } from '../../../types';
 
 jest.mock('../../app_context', () => ({
   appContextService: {
+    getInternalUserSOClient: () => {
+      return {};
+    },
     getEncryptedSavedObjects: () => ({
       getDecryptedAsInternalUser: () => ({
         attributes: {
@@ -19,7 +27,83 @@ jest.mock('../../app_context', () => ({
   },
 }));
 
+jest.mock('../actions');
+
+jest.useFakeTimers();
+
+function waitForPromiseResolved() {
+  return new Promise((resolve) => setImmediate(resolve));
+}
+
+function getMockedNewActionSince() {
+  return getNewActionsSince as jest.MockedFunction<typeof getNewActionsSince>;
+}
+
 describe('test agent checkin new action services', () => {
+  describe('newAgetActionObservable', () => {
+    beforeEach(() => {
+      (getNewActionsSince as jest.MockedFunction<typeof getNewActionsSince>).mockReset();
+    });
+    it('should work, call get actions until there is new action', async () => {
+      const observable = createNewActionsSharedObservable();
+
+      getMockedNewActionSince()
+        .mockResolvedValueOnce([])
+        .mockResolvedValueOnce([
+          ({ id: 'action1', created_at: new Date().toISOString() } as unknown) as AgentAction,
+        ])
+        .mockResolvedValueOnce([
+          ({ id: 'action2', created_at: new Date().toISOString() } as unknown) as AgentAction,
+        ]);
+      // First call
+      const promise = observable.pipe(take(1)).toPromise();
+
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+
+      const res = await promise;
+      expect(getNewActionsSince).toBeCalledTimes(2);
+      expect(res).toHaveLength(1);
+      expect(res[0].id).toBe('action1');
+      // Second call
+      const secondSubscription = observable.pipe(take(1)).toPromise();
+
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+
+      const secondRes = await secondSubscription;
+      expect(secondRes).toHaveLength(1);
+      expect(secondRes[0].id).toBe('action2');
+      expect(getNewActionsSince).toBeCalledTimes(3);
+      // It should call getNewActionsSince with the last action returned
+      expect(getMockedNewActionSince().mock.calls[2][1]).toBe(res[0].created_at);
+    });
+
+    it('should not fetch actions concurrently', async () => {
+      const observable = createNewActionsSharedObservable();
+
+      const resolves: Array<() => void> = [];
+      getMockedNewActionSince().mockImplementation(() => {
+        return new Promise((resolve) => {
+          resolves.push(resolve);
+        });
+      });
+
+      observable.pipe(take(1)).toPromise();
+
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+      jest.advanceTimersByTime(5000);
+      await waitForPromiseResolved();
+
+      expect(getNewActionsSince).toBeCalledTimes(1);
+    });
+  });
+
   describe('createAgentActionFromPolicyAction()', () => {
     const mockSavedObjectsClient = savedObjectsClientMock.create();
     const mockAgent: Agent = {

x-pack/plugins/ingest_manager/server/services/agents/checkin/state_new_actions.ts

@@ -12,6 +12,7 @@ import {
   share,
   distinctUntilKeyChanged,
   switchMap,
+  exhaustMap,
   concatMap,
   merge,
   filter,
@@ -62,18 +63,28 @@ function getInternalUserSOClient() {
   return appContextService.getInternalUserSOClient(fakeRequest);
 }
 
-function createNewActionsSharedObservable(): Observable<AgentAction[]> {
+export function createNewActionsSharedObservable(): Observable<AgentAction[]> {
   let lastTimestamp = new Date().toISOString();
 
   return timer(0, AGENT_UPDATE_ACTIONS_INTERVAL_MS).pipe(
-    switchMap(() => {
+    exhaustMap(() => {
       const internalSOClient = getInternalUserSOClient();
 
-      const timestamp = lastTimestamp;
-      lastTimestamp = new Date().toISOString();
-      return from(getNewActionsSince(internalSOClient, timestamp));
+      return from(
+        getNewActionsSince(internalSOClient, lastTimestamp).then((data) => {
+          if (data.length > 0) {
+            lastTimestamp = data.reduce((acc, action) => {
+              return acc >= action.created_at ? acc : action.created_at;
+            }, lastTimestamp);
+          }
+
+          return data;
+        })
+      );
+    }),
+    filter((data) => {
+      return data.length > 0;
     }),
-    filter((data) => data.length > 0),
     share()
   );
 }