[8.0] Ensure logstash getNodes always contains a uuid (#124201) (#124319)

* Ensure logstash getNodes always contains a uuid (#124201)

This is less of an issue on main since we've stopped querying `metricbeat-*` but might become important when we start doing agent testing (`metrics-*`).

On 8.0 it's easy to have error documents land in `metricbeat-*` for standalone logstash and break the UI.

(cherry picked from commit fb1ca61db5)

# Conflicts:
#	x-pack/plugins/monitoring/server/lib/logstash/get_nodes.ts

* No global stubs required in 8.0 branch

x-pack/plugins/monitoring/server/lib/logstash/get_nodes.test.ts

@@ -0,0 +1,60 @@
+/*
+ * 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 { getNodes } from './get_nodes';
+import { INDEX_PATTERN_LOGSTASH, STANDALONE_CLUSTER_CLUSTER_UUID } from '../../../common/constants';
+import { LegacyRequest } from '../../types';
+
+describe('getNodes', () => {
+  it('ensures collapse key is present query responses', async () => {
+    const configs: { [key: string]: number } = { 'monitoring.ui.max_bucket_size': 10000 };
+    const config = {
+      get: jest.fn().mockImplementation((key: string) => configs[key]),
+    };
+
+    const response = {};
+    const callWithRequest = jest.fn().mockResolvedValue(response);
+
+    const req = {
+      server: {
+        config() {
+          return config;
+        },
+        plugins: {
+          elasticsearch: {
+            getCluster: () => ({
+              callWithRequest,
+            }),
+          },
+        },
+      },
+      payload: {
+        // borrowed from detail_drawer.test.js
+        timeRange: {
+          min: 1516131138639,
+          max: 1516135440463,
+        },
+      },
+    } as unknown as LegacyRequest;
+
+    await getNodes(req, INDEX_PATTERN_LOGSTASH, {
+      clusterUuid: STANDALONE_CLUSTER_CLUSTER_UUID,
+    });
+
+    expect(callWithRequest.mock.calls.length).toBe(1);
+    expect(callWithRequest.mock.calls[0].length).toBe(3);
+
+    const filters = callWithRequest.mock.calls[0][2].body.query.bool.filter;
+    expect(filters).toContainEqual(
+      expect.objectContaining({
+        exists: {
+          field: 'logstash_stats.logstash.uuid',
+        },
+      })
+    );
+  });
+});

x-pack/plugins/monitoring/server/lib/logstash/get_nodes.ts

@@ -75,12 +75,15 @@ export async function getNodes(
   const start = moment.utc(req.payload.timeRange.min).valueOf();
   const end = moment.utc(req.payload.timeRange.max).valueOf();
 
+  const filters = [{ exists: { field: 'logstash_stats.logstash.uuid' } }];
+
   const params = {
     index: lsIndexPattern,
     size: config.get('monitoring.ui.max_bucket_size'), // FIXME
     ignore_unavailable: true,
     body: {
       query: createQuery({
+        filters,
         start,
         end,
         clusterUuid,