[ECO][Inventory v2] Ad hoc data view: Add get entities definition end…

…point using sources (elastic#203424)

Closes elastic#202298 
⚠️ Depends on elastic#203246

## Summary

This PR changes the way we get the entity index patterns to v2. It
creates an endpoint part of the inventory API which returns the index
patterns by entity type.

## Testing

⚠️ Currently in order to test we need to create the definition using the
dev tools manually before this
[PR](elastic#203246) is merged

- Open Dev tools and add a definition for an existing entity type
(example with host)
 ```
POST kbn:/internal/entities/v2/definitions/sources
{
  "source": {
    "id": "host_id",
    "type_id": "host",
    "index_patterns": ["metrics-*", "metricbeat-*"],
    "identity_fields": ["host.name"],
    "metadata_fields": [],
    "filters": [],
    "timestamp_field": "@timestamp"
  }
 ```

### Test the endpoint: 
- Open Dev tools and add
` GET kbn:/internal/inventory/entity/definitions/sources?type=host `
- Response: 
<img width="408" alt="image"
src="https://github.com/user-attachments/assets/1c7416b0-50a4-4e63-8081-928ec7856ff8">

### Test in the UI
- After the previous steps add some host data (oblt cluster /
metricbeat) or use synthtrace (for example use `node scripts/synthtrace
infra_hosts_with_apm_hosts --scenarioOpts.numInstances=10`)
- Go to Inventory and expand the host group
- Click on the actions button for any host and click on the Discover
link
- The correct dataview should be selected based on the created
definition
The same can be done for other entity types


https://github.com/user-attachments/assets/c9c3a7ae-daff-4d4b-b1b7-898c3f1603c6

---------

Co-authored-by: Carlos Crespo <[email protected]>

x-pack/plugins/observability_solution/inventory/public/components/entity_actions/index.tsx

@@ -24,17 +24,18 @@ export const EntityActions = ({ entity, setShowActions }: Props) => {
     ? `inventoryEntityActionsButton-${entity.entityDisplayName}`
     : 'inventoryEntityActionsButton';
 
-  const { getDiscoverEntitiesRedirectUrl, isEntityDefinitionLoading } = useDiscoverRedirect(entity);
+  const { getDiscoverEntitiesRedirectUrl, isEntityDefinitionIndexPatternsLoading } =
+    useDiscoverRedirect(entity);
   const discoverUrl = getDiscoverEntitiesRedirectUrl();
 
   const actions: React.ReactElement[] = [];
 
-  if (!discoverUrl && !isEntityDefinitionLoading) {
+  if (!discoverUrl && !isEntityDefinitionIndexPatternsLoading) {
     setShowActions(false);
     return null;
   }
 
-  if (!isEntityDefinitionLoading) {
+  if (!isEntityDefinitionIndexPatternsLoading) {
     actions.push(
       <EuiContextMenuItem
         data-test-subj="inventoryEntityActionExploreInDiscover"
@@ -65,7 +66,7 @@ export const EntityActions = ({ entity, setShowActions }: Props) => {
           iconType="boxesHorizontal"
           color="text"
           onClick={togglePopover}
-          isLoading={isEntityDefinitionLoading}
+          isLoading={isEntityDefinitionIndexPatternsLoading}
         />
       }
       closePopover={closePopover}

x-pack/plugins/observability_solution/inventory/public/hooks/use_discover_redirect.ts

@@ -7,23 +7,22 @@
 import { useCallback, useMemo } from 'react';
 import type { InventoryEntity } from '../../common/entities';
 import { useAdHocDataView } from './use_adhoc_data_view';
-import { useFetchEntityDefinition } from './use_fetch_entity_definition';
+import { useFetchEntityDefinitionIndexPattern } from './use_fetch_entity_definition_index_patterns';
 import { useKibana } from './use_kibana';
 
 export const useDiscoverRedirect = (entity: InventoryEntity) => {
   const {
     services: { share, application, entityManager },
   } = useKibana();
-  const { entityDefinitions, isEntityDefinitionLoading } = useFetchEntityDefinition(
-    entity.entityDefinitionId
-  );
+  const { entityDefinitionIndexPatterns, isEntityDefinitionIndexPatternsLoading } =
+    useFetchEntityDefinitionIndexPattern(entity.entityType);
 
   const title = useMemo(
     () =>
-      !isEntityDefinitionLoading && entityDefinitions && entityDefinitions?.length > 0
-        ? entityDefinitions[0]?.indexPatterns?.join(',')
+      !isEntityDefinitionIndexPatternsLoading && (entityDefinitionIndexPatterns ?? []).length > 0
+        ? entityDefinitionIndexPatterns[0].join()
         : '',
-    [entityDefinitions, isEntityDefinitionLoading]
+    [entityDefinitionIndexPatterns, isEntityDefinitionIndexPatternsLoading]
   );
 
   const { dataView } = useAdHocDataView(title);
@@ -54,5 +53,5 @@ export const useDiscoverRedirect = (entity: InventoryEntity) => {
     entityManager.entityClient,
   ]);
 
-  return { getDiscoverEntitiesRedirectUrl, isEntityDefinitionLoading };
+  return { getDiscoverEntitiesRedirectUrl, isEntityDefinitionIndexPatternsLoading };
 };

x-pack/plugins/observability_solution/inventory/public/hooks/use_fetch_entity_definition_index_patterns.ts

@@ -0,0 +1,34 @@
+/*
+ * 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 { useInventoryAbortableAsync } from './use_inventory_abortable_async';
+import { useKibana } from './use_kibana';
+
+export const useFetchEntityDefinitionIndexPattern = (type: string) => {
+  const {
+    services: { inventoryAPIClient },
+  } = useKibana();
+
+  const { value = { definitionIndexPatterns: [] }, loading } = useInventoryAbortableAsync(
+    ({ signal }) => {
+      return inventoryAPIClient.fetch('GET /internal/inventory/entity/definitions/sources', {
+        params: {
+          query: {
+            type,
+          },
+        },
+        signal,
+      });
+    },
+    [inventoryAPIClient]
+  );
+
+  return {
+    entityDefinitionIndexPatterns: value?.definitionIndexPatterns,
+    isEntityDefinitionIndexPatternsLoading: loading,
+  };
+};

x-pack/plugins/observability_solution/inventory/server/routes/entity_definition/get_entity_definitions.ts

@@ -0,0 +1,41 @@
+/*
+ * 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 * as t from 'io-ts';
+import { createInventoryServerRoute } from '../create_inventory_server_route';
+
+export const getEntityDefinitionSourceIndexPatternsByType = createInventoryServerRoute({
+  endpoint: 'GET /internal/inventory/entity/definitions/sources',
+  params: t.type({
+    query: t.type({
+      type: t.string,
+    }),
+  }),
+  options: {
+    tags: ['access:inventory'],
+  },
+  async handler({ context, params, request, plugins }) {
+    const [_coreContext, entityManagerStart] = await Promise.all([
+      context.core,
+      plugins.entityManager.start(),
+    ]);
+    const { type } = params.query;
+    const entityManagerClient = await entityManagerStart.getScopedClient({ request });
+
+    const entityDefinitionsSource = await entityManagerClient.v2.readSourceDefinitions({ type });
+
+    return {
+      definitionIndexPatterns: entityDefinitionsSource.map(
+        (definition) => definition.index_patterns,
+        []
+      ),
+    };
+  },
+});
+
+export const entityDefinitionsRoutes = {
+  ...getEntityDefinitionSourceIndexPatternsByType,
+};

x-pack/plugins/observability_solution/inventory/server/routes/get_global_inventory_route_repository.ts

@@ -6,11 +6,13 @@
  */
 
 import { entitiesRoutes } from './entities/route';
+import { entityDefinitionsRoutes } from './entity_definition/get_entity_definitions';
 import { hasDataRoutes } from './has_data/route';
 
 export function getGlobalInventoryServerRouteRepository() {
   return {
     ...entitiesRoutes,
+    ...entityDefinitionsRoutes,
     ...hasDataRoutes,
   };
 }