[Obs AI Assistant] Specify embedding model during onboarding for the Knowledge Base (elastic#218448)

Closes elastic/obs-ai-team#230
Closes elastic/obs-ai-team#232

Related to elastic#215591

## Summary

This PR implements the changes related to the first phase of supporing
multilingual Knowledge Base. The users have the ability to pick the
`e5-small` model for the Knowledge Base, if they want support for
languages other than English.

<img width="610" alt="image"
src="https://github.com/user-attachments/assets/4c815aa4-aa97-4845-98c5-e079dd92f23a"
/>

<img width="1281" alt="image"
src="https://github.com/user-attachments/assets/7c1bcd82-5464-497f-a053-7fe271da1cdd"
/>

<img width="1280" alt="image"
src="https://github.com/user-attachments/assets/bc084e90-c291-44ea-8560-e033729bfcca"
/>

When the KB model is not allocated due to nodes scaling down:


![image](https://github.com/user-attachments/assets/2f52e31e-81e4-4824-bc5b-b97df714da5c)


### Checklist

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/src/platform/packages/shared/kbn-i18n/README.md)
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [ ] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)


## Upgrade testing steps

### 9.0 - 9.1 (main)

Checkout `9.0` branch and start Kibana and ES. ES must be started with
`path.data` to persist data:

```
yarn es snapshot --license trial --E path.data=/Users/sorenlouv/elastic/es_data/upgrade_test_9.0
```

---------

Co-authored-by: Søren Louv-Jansen <soren.louv@elastic.co>
Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: Søren Louv-Jansen <sorenlouv@gmail.com>

Author: 4 people

packages/kbn-lock-manager/src/lock_manager_client.ts

@@ -256,6 +256,19 @@ export class LockManager {
   }
 }
 
+export async function getLock({
+  esClient,
+  logger,
+  lockId,
+}: {
+  esClient: ElasticsearchClient;
+  logger: Logger;
+  lockId: LockId;
+}): Promise<LockDocument | undefined> {
+  const lockManager = new LockManager(lockId, esClient, logger);
+  return lockManager.get();
+}
+
 export async function withLock<T>(
   {
     esClient,
@@ -280,9 +293,7 @@ export async function withLock<T>(
 
   // extend the ttl periodically
   const extendInterval = Math.floor(ttl / 4);
-  logger.debug(
-    `Lock "${lockId}" acquired. Extending TTL every ${prettyMilliseconds(extendInterval)}`
-  );
+  logger.debug(`Extending TTL for lock "${lockId}" every ${prettyMilliseconds(extendInterval)}`);
 
   let extendTTlPromise = Promise.resolve(true);
   const intervalId = setInterval(() => {

packages/kbn-lock-manager/src/lock_manager_service.ts

@@ -8,7 +8,7 @@
  */
 
 import { CoreSetup, Logger } from '@kbn/core/server';
-import { LockId, withLock } from './lock_manager_client';
+import { LockId, withLock, getLock } from './lock_manager_client';
 
 export class LockManagerService {
   constructor(private readonly coreSetup: CoreSetup<any>, private readonly logger: Logger) {}
@@ -35,8 +35,16 @@ export class LockManagerService {
   ) {
     const [coreStart] = await this.coreSetup.getStartServices();
     const esClient = coreStart.elasticsearch.client.asInternalUser;
-    const logger = this.logger.get('LockManager');
+    const logger = this.logger.get('lock-manager');
 
     return withLock<T>({ esClient, logger, lockId, metadata }, callback);
   }
+
+  async getLock(lockId: LockId) {
+    const [coreStart] = await this.coreSetup.getStartServices();
+    const esClient = coreStart.elasticsearch.client.asInternalUser;
+    const logger = this.logger.get('lock-manager');
+
+    return getLock({ esClient, logger, lockId });
+  }
 }

src/dev/run_check_file_casing.ts

@@ -34,6 +34,9 @@ run(async ({ log }) => {
       'src/platform/**',
       'x-pack/platform/**',
       'x-pack/solutions/**',
+
+      // ignore autogenerated snapshots
+      'x-pack/test/api_integration/deployment_agnostic/apis/observability/ai_assistant/knowledge_base/snapshots',
     ],
   });
 

x-pack/platform/packages/shared/kbn-ai-assistant/src/chat/welcome_message.tsx

@@ -12,12 +12,11 @@ import type { ActionConnector } from '@kbn/triggers-actions-ui-plugin/public';
 import { GenerativeAIForObservabilityConnectorFeatureId } from '@kbn/actions-plugin/common';
 import { isSupportedConnectorType } from '@kbn/inference-common';
 import { AssistantBeacon } from '@kbn/ai-assistant-icon';
-import { KnowledgeBaseState } from '@kbn/observability-ai-assistant-plugin/public';
 import type { UseKnowledgeBaseResult } from '../hooks/use_knowledge_base';
 import type { UseGenAIConnectorsResult } from '../hooks/use_genai_connectors';
 import { Disclaimer } from './disclaimer';
 import { WelcomeMessageConnectors } from './welcome_message_connectors';
-import { WelcomeMessageKnowledgeBase } from './welcome_message_knowledge_base';
+import { WelcomeMessageKnowledgeBase } from '../knowledge_base/welcome_message_knowledge_base';
 import { StarterPrompts } from './starter_prompts';
 import { useKibana } from '../hooks/use_kibana';
 
@@ -61,13 +60,6 @@ export function WelcomeMessage({
     if (isSupportedConnectorType(createdConnector.actionTypeId)) {
       connectors.reloadConnectors();
     }
-
-    if (
-      !knowledgeBase.status.value ||
-      knowledgeBase.status.value?.kbState === KnowledgeBaseState.NOT_INSTALLED
-    ) {
-      knowledgeBase.install();
-    }
   };
 
   const ConnectorFlyout = useMemo(

x-pack/platform/packages/shared/kbn-ai-assistant/src/chat/welcome_message_connectors.tsx

@@ -22,7 +22,7 @@ import { i18n } from '@kbn/i18n';
 import { isHttpFetchError } from '@kbn/core-http-browser';
 import type { UseGenAIConnectorsResult } from '../hooks/use_genai_connectors';
 
-const fadeInAnimation = keyframes`
+export const fadeInAnimation = keyframes`
   from {
     opacity: 0;
   }

x-pack/platform/packages/shared/kbn-ai-assistant/src/chat/welcome_message_knowledge_base.tsx

@@ -20,7 +20,12 @@ export function useKnowledgeBase(): UseKnowledgeBaseResult {
       value: {
         kbState: KnowledgeBaseState.NOT_INSTALLED,
         enabled: true,
+        concreteWriteIndex: undefined,
+        currentInferenceId: undefined,
+        isReIndexing: false,
       },
     },
+    warmupModel: async () => {},
+    isWarmingUpModel: false,
   };
 }

x-pack/platform/packages/shared/kbn-ai-assistant/src/hooks/__storybook_mocks__/use_knowledge_base.ts

@@ -0,0 +1,82 @@
+/*
+ * 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; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { renderHook, act } from '@testing-library/react';
+import { useInferenceEndpoints } from './use_inference_endpoints';
+import { useAIAssistantAppService } from './use_ai_assistant_app_service';
+
+jest.mock('./use_ai_assistant_app_service');
+
+describe('useInferenceEndpoints', () => {
+  const mockCallApi = jest.fn();
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+
+    (useAIAssistantAppService as jest.Mock).mockReturnValue({
+      callApi: mockCallApi,
+    });
+  });
+
+  it('fetches inference endpoints successfully on mount', async () => {
+    const mockResponse = {
+      endpoints: [
+        { id: '1', name: 'Endpoint 1' },
+        { id: '2', name: 'Endpoint 2' },
+      ],
+    };
+
+    mockCallApi.mockResolvedValueOnce(mockResponse);
+
+    const { result } = renderHook(() => useInferenceEndpoints());
+
+    await act(async () => {
+      await Promise.resolve();
+    });
+
+    expect(mockCallApi).toHaveBeenCalledWith(
+      'GET /internal/observability_ai_assistant/kb/inference_endpoints',
+      {
+        signal: expect.any(AbortSignal),
+      }
+    );
+
+    expect(result.current.inferenceEndpoints).toEqual(mockResponse.endpoints);
+    expect(result.current.isLoading).toBe(false);
+    expect(result.current.error).toBeUndefined();
+  });
+
+  it('sets an error state on API errors', async () => {
+    const error = new Error('Something went wrong');
+    mockCallApi.mockRejectedValueOnce(error);
+
+    const { result } = renderHook(() => useInferenceEndpoints());
+
+    await act(async () => {
+      await Promise.resolve();
+    });
+
+    expect(result.current.inferenceEndpoints).toEqual([]);
+    expect(result.current.isLoading).toBe(false);
+    expect(result.current.error).toEqual(error);
+  });
+
+  it('ignores AbortError and does not set error state', async () => {
+    const abortError = new DOMException('Aborted', 'AbortError');
+    mockCallApi.mockRejectedValueOnce(abortError);
+
+    const { result } = renderHook(() => useInferenceEndpoints());
+
+    await act(async () => {
+      await Promise.resolve();
+    });
+
+    expect(result.current.inferenceEndpoints).toEqual([]);
+    expect(result.current.isLoading).toBe(false);
+    expect(result.current.error).toBeUndefined();
+  });
+});