[Search] Support non-shard error information in ES responses (#81967) (…

…#82073)

* Display top-level error reason if no shard info is available

For EQL queries, error responses do not contain `failed_shards`
information, and so our error toasts contained only a stack trace.

With this addition, we'll fall back to the top-level `error.reason` if
those fields are not present, giving the user better indication of
what's going on without having to inspect the actual network response.

* Prevent service from changing the shape of our errors

This ensures a consistent interface for our kibana client errors,
whether the error is raised directly from a `fetch` or emitted from a
search strategy's observable; namely: that both contain this top-level
`body` key.

* Make our body property public

This is the same visibility as the original error: if it were protected it
wouldn't be very useful to consumers.

* Adds a unit test for the interface adherence

src/plugins/data/public/search/errors/es_error.test.tsx

@@ -0,0 +1,40 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { EsError } from './es_error';
+import { IEsError } from './types';
+
+describe('EsError', () => {
+  it('contains the same body as the wrapped error', () => {
+    const error = {
+      body: {
+        attributes: {
+          error: {
+            type: 'top_level_exception_type',
+            reason: 'top-level reason',
+          },
+        },
+      },
+    } as IEsError;
+    const esError = new EsError(error);
+
+    expect(typeof esError.body).toEqual('object');
+    expect(esError.body).toEqual(error.body);
+  });
+});

src/plugins/data/public/search/errors/es_error.tsx

@@ -22,22 +22,27 @@ import { EuiCodeBlock, EuiSpacer } from '@elastic/eui';
 import { ApplicationStart } from 'kibana/public';
 import { KbnError } from '../../../../kibana_utils/common';
 import { IEsError } from './types';
-import { getRootCause } from './utils';
+import { getRootCause, getTopLevelCause } from './utils';
 
 export class EsError extends KbnError {
+  readonly body: IEsError['body'];
+
   constructor(protected readonly err: IEsError) {
     super('EsError');
+    this.body = err.body;
   }
 
   public getErrorMessage(application: ApplicationStart) {
     const rootCause = getRootCause(this.err)?.reason;
+    const topLevelCause = getTopLevelCause(this.err)?.reason;
+    const cause = rootCause ?? topLevelCause;
 
     return (
       <>
         <EuiSpacer size="s" />
-        {rootCause ? (
+        {cause ? (
           <EuiCodeBlock data-test-subj="errMessage" isCopyable={true} paddingSize="s">
-            {rootCause}
+            {cause}
           </EuiCodeBlock>
         ) : null}
       </>

src/plugins/data/public/search/errors/utils.ts

@@ -26,6 +26,10 @@ export function getFailedShards(err: IEsError) {
   return failedShards ? failedShards[0] : undefined;
 }
 
+export function getTopLevelCause(err: IEsError) {
+  return err.body?.attributes?.error;
+}
+
 export function getRootCause(err: IEsError) {
   return getFailedShards(err)?.reason;
 }