Backport PR #8764

---------

**Commit 1:**
UI Settings disabled when plugins.initialize is false

* Original sha: c6f90e2fd3
* Authored by = <brandon.kobel@elastic.co> on 2016-10-19T20:47:05Z

**Commit 2:**
Moving where we're disabling the ui settings

* Original sha: e66c7e79f9
* Authored by = <brandon.kobel@elastic.co> on 2016-10-19T21:22:52Z

**Commit 3:**
[server/uiSettings] add enabled config

in response to matt's comment that relying on `plugins.initialize` is kinda dirty (with which we all agree) we're adding an undocumented config value that the dev cli can use to put prevent the optimizr server from logging meaningless warnings

* Original sha: 40ffd12238
* Authored by spalger <email@spalger.com> on 2016-10-19T23:24:55Z

**Commit 4:**
[server/uiSettings] react to missing elasticsearch plugin

* Original sha: 7feacf6a70
* Authored by spalger <email@spalger.com> on 2016-10-19T23:26:44Z

**Commit 5:**
[server/uiSettings] fix da tests

* Original sha: c2d7d0136a
* Authored by spalger <email@spalger.com> on 2016-10-19T23:36:11Z

**Commit 6:**
[server/uiSettings] document enabled config

* Original sha: f9bd154fcd
* Authored by Spencer <spalger@users.noreply.github.com> on 2016-10-19T23:52:28Z
* Committed by GitHub <noreply@github.com> on 2016-10-19T23:52:28Z

src/cli/cluster/cluster_manager.js

@@ -18,6 +18,7 @@ module.exports = class ClusterManager {
     const serverArgv = [];
     const optimizerArgv = [
       '--plugins.initialize=false',
+      '--uiSettings.enabled=false',
       '--server.autoListen=false',
     ];
 

src/server/config/schema.js

@@ -145,6 +145,14 @@ module.exports = () => Joi.object({
       reuseTiles: Joi.boolean(),
       bounds: Joi.array().items(Joi.array().items(Joi.number()).min(2).required()).min(2)
     }).default()
-  }).default()
+  }).default(),
+
+  uiSettings: Joi.object({ 
+    // this is used to prevent the uiSettings from initializing. Since they
+    // require the elasticsearch plugin in order to function we need to turn
+    // them off when we turn off the elasticsearch plugin (like we do in the
+    // optimizer half of the dev server)
+    enabled: Joi.boolean().default(true)
+  }).default(),
 
 }).default();

src/ui/settings/__tests__/index.js

@@ -322,6 +322,7 @@ function instantiate({ getResult } = {}) {
   const configGet = sinon.stub();
   configGet.withArgs('kibana.index').returns('.kibana');
   configGet.withArgs('pkg.version').returns('1.2.3-test');
+  configGet.withArgs('uiSettings.enabled').returns(true);
   const config = {
     get: configGet
   };

src/ui/settings/index.js

@@ -3,6 +3,12 @@ import defaultsProvider from './defaults';
 
 export default function setupSettings(kbnServer, server, config) {
   const status = kbnServer.status.create('ui settings');
+
+  if (!config.get('uiSettings.enabled')) {
+    status.disabled('uiSettings.enabled config is set to `false`');
+    return;
+  }
+
   const uiSettings = {
     // returns a Promise for the value of the requested setting
     get,
@@ -99,6 +105,11 @@ export default function setupSettings(kbnServer, server, config) {
   function mirrorEsStatus() {
     const esStatus = kbnServer.status.getForPluginId('elasticsearch');
 
+    if (!esStatus) {
+      status.red('UI Settings requires the elasticsearch plugin');
+      return;
+    }
+
     copyStatus();
     esStatus.on('change', copyStatus);