redact ES client errors (#171018)

## Summary

Define a custom `toJSON` method on errors from the ES client to have
better control of the format of the output of their JSON serialization

packages/core/elasticsearch/core-elasticsearch-client-server-internal/src/configure_client.ts

@@ -13,9 +13,13 @@ import { parseClientOptions } from './client_config';
 import { instrumentEsQueryAndDeprecationLogger } from './log_query_and_deprecation';
 import { createTransport } from './create_transport';
 import type { AgentFactoryProvider } from './agent_manager';
+import { patchElasticsearchClient } from './patch_client';
 
 const noop = () => undefined;
 
+// Apply ES client patches on module load
+patchElasticsearchClient();
+
 export const configureClient = (
   config: ElasticsearchClientConfig,
   {

packages/core/elasticsearch/core-elasticsearch-client-server-internal/src/patch_client.ts

@@ -0,0 +1,20 @@
+/*
+ * 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 { errors } from '@elastic/elasticsearch';
+
+export const patchElasticsearchClient = () => {
+  const baseErrorPrototype = errors.ElasticsearchClientError.prototype;
+  // @ts-expect-error
+  baseErrorPrototype.toJSON = function () {
+    return {
+      name: this.name,
+      message: this.message,
+    };
+  };
+};

src/core/server/integration_tests/elasticsearch/errors.test.ts

@@ -0,0 +1,70 @@
+/*
+ * 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 {
+  createTestServers,
+  type TestElasticsearchUtils,
+  type TestKibanaUtils,
+} from '@kbn/core-test-helpers-kbn-server';
+
+describe('elasticsearch clients errors', () => {
+  let esServer: TestElasticsearchUtils;
+  let kibanaServer: TestKibanaUtils;
+
+  beforeAll(async () => {
+    const { startES, startKibana } = createTestServers({
+      adjustTimeout: jest.setTimeout,
+    });
+
+    esServer = await startES();
+    kibanaServer = await startKibana();
+  });
+
+  afterAll(async () => {
+    await kibanaServer.stop();
+    await esServer.stop();
+  });
+
+  it('has the proper JSON representation', async () => {
+    const esClient = kibanaServer.coreStart.elasticsearch.client.asInternalUser;
+
+    try {
+      await esClient.search({
+        index: '.kibana',
+        // @ts-expect-error yes this is invalid
+        query: { someInvalidQuery: { foo: 'bar' } },
+      });
+      expect('should have thrown').toEqual('but it did not');
+    } catch (e) {
+      expect(JSON.stringify(e)).toMatchInlineSnapshot(
+        `"{\\"name\\":\\"ResponseError\\",\\"message\\":\\"parsing_exception\\\\n\\\\tCaused by:\\\\n\\\\t\\\\tnamed_object_not_found_exception: [1:30] unknown field [someInvalidQuery]\\\\n\\\\tRoot causes:\\\\n\\\\t\\\\tparsing_exception: unknown query [someInvalidQuery]\\"}"`
+      );
+    }
+  });
+
+  it('has the proper string representation', async () => {
+    const esClient = kibanaServer.coreStart.elasticsearch.client.asInternalUser;
+
+    try {
+      await esClient.search({
+        index: '.kibana',
+        // @ts-expect-error yes this is invalid
+        query: { someInvalidQuery: { foo: 'bar' } },
+      });
+      expect('should have thrown').toEqual('but it did not');
+    } catch (e) {
+      expect(String(e)).toMatchInlineSnapshot(`
+        "ResponseError: parsing_exception
+        	Caused by:
+        		named_object_not_found_exception: [1:30] unknown field [someInvalidQuery]
+        	Root causes:
+        		parsing_exception: unknown query [someInvalidQuery]"
+      `);
+    }
+  });
+});