[7.17] redact ES client errors (#171018) (#171030)

# Backport

This will backport the following commits from `main` to `7.17`:
- [redact ES client errors
(#171018)](#171018)

<!--- Backport version: 8.9.8 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Pierre
Gayvallet","email":"[email protected]"},"sourceCommit":{"committedDate":"2023-11-10T14:42:14Z","message":"redact
ES client errors (#171018)\n\n## Summary\r\n\r\nDefine a custom `toJSON`
method on errors from the ES client to have\r\nbetter control of the
format of the output of their JSON
serialization","sha":"c43e6997af35492577b07f196d25d11a6bec6f14","branchLabelMapping":{"^v8.12.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Feature:elasticsearch","Team:Core","release_note:skip","backport:prev-minor","v8.12.0"],"number":171018,"url":"https://github.com/elastic/kibana/pull/171018","mergeCommit":{"message":"redact
ES client errors (#171018)\n\n## Summary\r\n\r\nDefine a custom `toJSON`
method on errors from the ES client to have\r\nbetter control of the
format of the output of their JSON
serialization","sha":"c43e6997af35492577b07f196d25d11a6bec6f14"}},"sourceBranch":"main","suggestedTargetBranches":[],"targetPullRequestStates":[{"branch":"main","label":"v8.12.0","labelRegex":"^v8.12.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/171018","number":171018,"mergeCommit":{"message":"redact
ES client errors (#171018)\n\n## Summary\r\n\r\nDefine a custom `toJSON`
method on errors from the ES client to have\r\nbetter control of the
format of the output of their JSON
serialization","sha":"c43e6997af35492577b07f196d25d11a6bec6f14"}}]}]
BACKPORT-->

src/core/server/elasticsearch/client/configure_client.ts

@@ -15,9 +15,13 @@ import type {
 import { Logger } from '../../logging';
 import { parseClientOptions, ElasticsearchClientConfig } from './client_config';
 import { instrumentEsQueryAndDeprecationLogger } from './log_query_and_deprecation';
+import { patchElasticsearchClient } from './patch_client';
 
 const noop = () => undefined;
 
+// Apply ES client patches on module load
+patchElasticsearchClient();
+
 export const configureClient = (
   config: ElasticsearchClientConfig,
   {

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

@@ -0,0 +1,49 @@
+/*
+ * 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 '../../../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) {
+      const stringifiedError = JSON.stringify(e);
+      expect(stringifiedError).not.toContain('headers');
+      expect(stringifiedError).not.toContain('authorization');
+    }
+  });
+});