[eem] prevent customization of builtin definitions (elastic#192593)

We allow users to define `@platform` and `@custom` ingest
pipelines/index templates to customize entity definitions output. This
change prevents builtin definitions from being customized

x-pack/plugins/observability_solution/entity_manager/server/lib/entities/helpers/is_builtin_definition.ts

@@ -0,0 +1,13 @@
+/*
+ * 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 { EntityDefinition } from '@kbn/entities-schema';
+import { BUILT_IN_ID_PREFIX } from '../built_in';
+
+export function isBuiltinDefinition(definition: EntityDefinition) {
+  return definition.id.startsWith(BUILT_IN_ID_PREFIX);
+}

x-pack/plugins/observability_solution/entity_manager/server/lib/entities/ingest_pipeline/generate_history_processors.test.ts

@@ -5,12 +5,17 @@
  * 2.0.
  */
 
-import { entityDefinition } from '../helpers/fixtures/entity_definition';
+import { entityDefinition, builtInEntityDefinition } from '../helpers/fixtures';
 import { generateHistoryProcessors } from './generate_history_processors';
 
 describe('generateHistoryProcessors(definition)', () => {
-  it('should genearte a valid pipeline', () => {
+  it('should generate a valid pipeline for custom definition', () => {
     const processors = generateHistoryProcessors(entityDefinition);
     expect(processors).toMatchSnapshot();
   });
+
+  it('should generate a valid pipeline for builtin definition', () => {
+    const processors = generateHistoryProcessors(builtInEntityDefinition);
+    expect(processors).toMatchSnapshot();
+  });
 });

x-pack/plugins/observability_solution/entity_manager/server/lib/entities/ingest_pipeline/generate_history_processors.ts

@@ -11,6 +11,7 @@ import {
   cleanScript,
 } from '../helpers/ingest_pipeline_script_processor_helpers';
 import { generateHistoryIndexName } from '../helpers/generate_component_id';
+import { isBuiltinDefinition } from '../helpers/is_builtin_definition';
 
 function mapDestinationToPainless(field: string) {
   return `
@@ -46,6 +47,39 @@ function liftIdentityFieldsToDocumentRoot(definition: EntityDefinition) {
   }));
 }
 
+function getCustomIngestPipelines(definition: EntityDefinition) {
+  if (isBuiltinDefinition(definition)) {
+    return [];
+  }
+
+  return [
+    {
+      pipeline: {
+        ignore_missing_pipeline: true,
+        name: `${definition.id}@platform`,
+      },
+    },
+    {
+      pipeline: {
+        ignore_missing_pipeline: true,
+        name: `${definition.id}-history@platform`,
+      },
+    },
+    {
+      pipeline: {
+        ignore_missing_pipeline: true,
+        name: `${definition.id}@custom`,
+      },
+    },
+    {
+      pipeline: {
+        ignore_missing_pipeline: true,
+        name: `${definition.id}-history@custom`,
+      },
+    },
+  ];
+}
+
 export function generateHistoryProcessors(definition: EntityDefinition) {
   return [
     {
@@ -162,30 +196,6 @@ export function generateHistoryProcessors(definition: EntityDefinition) {
         date_formats: ['UNIX_MS', 'ISO8601', "yyyy-MM-dd'T'HH:mm:ss.SSSXX"],
       },
     },
-    {
-      pipeline: {
-        ignore_missing_pipeline: true,
-        name: `${definition.id}@platform`,
-      },
-    },
-    {
-      pipeline: {
-        ignore_missing_pipeline: true,
-        name: `${definition.id}-history@platform`,
-      },
-    },
-
-    {
-      pipeline: {
-        ignore_missing_pipeline: true,
-        name: `${definition.id}@custom`,
-      },
-    },
-    {
-      pipeline: {
-        ignore_missing_pipeline: true,
-        name: `${definition.id}-history@custom`,
-      },
-    },
+    ...getCustomIngestPipelines(definition),
   ];
 }