Limit scripted fields to painless and expression langs (#9172)

We made a mistake in opening up Kibana scripted fields to any and all
langs enabled in Elasticsearch. Kibana needs to do some magic to get
certain scripted field features to work
(https://github.com/elastic/kibana/pull/9171) and we can't commit to
supporting anything beyond expression and painless scripts. On top of
that, the other languages are being removed in ES 6.0 anyway. This commit
makes that stance explicit by disallowing anything other than those two
choices.

docs/migration/migrate_6_0.asciidoc

@@ -1,4 +1,13 @@
 [[breaking-changes-6.0]]
 == Breaking changes in 6.0
 
-There are not yet any breaking changes in Kibana 6.0
+This section discusses the changes that you need to be aware of when migrating
+your application to Kibana 6.0.
+
+[float]
+=== Removed option to use unsupported scripting languages
+*Details:* Kibana 5.x allowed users to create scripted fields using any scripting language enabled in Elasticsearch.
+Kibana 6.0 will only support Painless and Lucene expression based scripts.
+
+
+*Impact:* You will need to migrate your groovy, python, javascript, etc. scripted fields to Painless or Lucene expressions.

src/ui/public/field_editor/field_editor.js

@@ -10,12 +10,14 @@ import chrome from 'ui/chrome';
 import IndexPatternsCastMappingTypeProvider from 'ui/index_patterns/_cast_mapping_type';
 import { scriptedFields as docLinks } from '../documentation_links/documentation_links';
 import './field_editor.less';
+import { GetEnabledScriptingLanguagesProvider, getSupportedScriptingLanguages } from '../scripting_languages';
 
 uiModules
 .get('kibana', ['colorpicker.module'])
 .directive('fieldEditor', function (Private, $sce) {
   let fieldFormats = Private(RegistryFieldFormatsProvider);
   let Field = Private(IndexPatternsFieldProvider);
+  let getEnabledScriptingLanguages = Private(GetEnabledScriptingLanguagesProvider);
 
   const fieldTypesByLang = {
     painless: ['number', 'string', 'date', 'boolean'],
@@ -37,7 +39,7 @@ uiModules
 
       self.docLinks = docLinks;
       getScriptingLangs().then((langs) => {
-        self.scriptingLangs = langs;
+        self.scriptingLangs = _.intersection(langs, ['expression', 'painless']);
         if (!_.includes(self.scriptingLangs, self.field.lang)) {
           self.field.lang = undefined;
         }
@@ -159,11 +161,9 @@ uiModules
       }
 
       function getScriptingLangs() {
-        return $http.get(chrome.addBasePath('/api/kibana/scripts/languages'))
-        .then((res) => res.data)
-        .catch(() => {
-          notify.error('Error getting available scripting languages from Elasticsearch');
-          return [];
+        return getEnabledScriptingLanguages()
+        .then((enabledLanguages) => {
+          return _.intersection(enabledLanguages, getSupportedScriptingLanguages());
         });
       }
 

src/ui/public/scripting_languages/index.js

@@ -0,0 +1,20 @@
+import chrome from 'ui/chrome';
+import Notifier from 'ui/notify/notifier';
+import { intersection } from 'lodash';
+
+const notify = new Notifier({ location: 'Scripting Language Service' });
+
+export function getSupportedScriptingLanguages() {
+  return ['expression', 'painless'];
+}
+
+export function GetEnabledScriptingLanguagesProvider($http) {
+  return () => {
+    return $http.get(chrome.addBasePath('/api/kibana/scripts/languages'))
+    .then((res) => res.data)
+    .catch(() => {
+      notify.error('Error getting available scripting languages from Elasticsearch');
+      return [];
+    });
+  };
+}