Elastic: Internal data links (#25942)

* Allow internal datalinks for elastic

* Add docs

* Update docs/sources/features/datasources/elasticsearch.md

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>

public/app/plugins/datasource/elasticsearch/datasource.test.ts

@@ -1,7 +1,17 @@
 import angular from 'angular';
-import { CoreApp, DataQueryRequest, DataSourceInstanceSettings, dateMath, dateTime, Field, toUtc } from '@grafana/data';
+import {
+  ArrayVector,
+  CoreApp,
+  DataQueryRequest,
+  DataSourceInstanceSettings,
+  dateMath,
+  dateTime,
+  Field,
+  MutableDataFrame,
+  toUtc,
+} from '@grafana/data';
 import _ from 'lodash';
-import { ElasticDatasource } from './datasource';
+import { ElasticDatasource, enhanceDataFrame } from './datasource';
 import { backendSrv } from 'app/core/services/backend_srv'; // will use the version in __mocks__
 import { TimeSrv } from 'app/features/dashboard/services/TimeSrv';
 import { TemplateSrv } from 'app/features/templating/template_srv';
@@ -849,6 +859,49 @@ describe('ElasticDatasource', function(this: any) {
   });
 });
 
+describe('enhanceDataFrame', () => {
+  it('adds links to dataframe', () => {
+    const df = new MutableDataFrame({
+      fields: [
+        {
+          name: 'urlField',
+          values: new ArrayVector([]),
+        },
+        {
+          name: 'traceField',
+          values: new ArrayVector([]),
+        },
+      ],
+    });
+    enhanceDataFrame(df, [
+      {
+        field: 'urlField',
+        url: 'someUrl',
+      },
+      {
+        field: 'traceField',
+        url: 'query',
+        datasourceUid: 'dsUid',
+      },
+    ]);
+
+    expect(df.fields[0].config.links.length).toBe(1);
+    expect(df.fields[0].config.links[0]).toEqual({
+      title: '',
+      url: 'someUrl',
+    });
+    expect(df.fields[1].config.links.length).toBe(1);
+    expect(df.fields[1].config.links[0]).toEqual({
+      title: '',
+      url: '',
+      internal: {
+        query: { query: 'query' },
+        datasourceUid: 'dsUid',
+      },
+    });
+  });
+});
+
 const createElasticQuery = (): DataQueryRequest<ElasticsearchQuery> => {
   return {
     requestId: '',