Add web UI to trigger full indexing

Indexing done in background job

ee/app/controllers/admin/elasticsearch_controller.rb

+# frozen_string_literal: true
+
+class Admin::ElasticsearchController < Admin::ApplicationController
+  before_action :check_elasticsearch_web_indexing_feature_flag!
+
+  def check_elasticsearch_web_indexing_feature_flag!
+    render_404 unless Feature.enabled?(:elasticsearch_web_indexing)
+  end
+
+  # POST
+  # Scheduling indexing jobs
+  def enqueue_index
+    ::Elastic::IndexProjectsService.new.execute
+
+    notice = _('Elasticsearch indexing started')
+    queue_link = helpers.link_to(_('(check progress)'), sidekiq_path + '/queues/elastic_full_index')
+    flash[:notice] = "#{notice} #{queue_link}".html_safe
+
+    redirect_back_or_default
+  end
+end

ee/app/views/admin/application_settings/_elasticsearch_form.html.haml

@@ -82,3 +82,11 @@
               AWS Secret Access Key.  Only required if not using role instance credentials
 
       = f.submit 'Save changes', class: "btn btn-success"
+
+    - if Feature.enabled?(:elasticsearch_web_indexing)
+      %br
+      %h4
+        = _('Indexing')
+
+      = form_with url: admin_elasticsearch_enqueue_index_path, html: { class: 'fieldset-form' }, data: { remote: false } do |f|
+        = f.submit _('Start Indexing'), class: "btn btn-success"

ee/changelogs/unreleased/5299-elastic-recovery.yml

+---
+title: Allowing Elasticsearch indexing gap recovering
+merge_request: 11408
+author:
+type: changed

ee/config/routes/admin.rb

@@ -44,5 +44,9 @@ namespace :admin do
     resources :uploads, only: [:index, :destroy]
   end
 
+  namespace :elasticsearch do
+    post :enqueue_index
+  end
+
   get '/dashboard/stats', to: 'dashboard#stats'
 end

ee/spec/controllers/admin/elasticsearch_controller_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Admin::ElasticsearchController do
+  let(:admin) { create(:admin) }
+
+  describe 'POST #enqueue_index' do
+    before do
+      sign_in(admin)
+    end
+
+    it 'starts indexing' do
+      expect_next_instance_of(::Elastic::IndexProjectsService) do |service|
+        expect(service).to receive(:execute)
+      end
+
+      post :enqueue_index
+
+      expect(controller).to set_flash[:notice].to include('/admin/sidekiq/queues/elastic_full_index')
+    end
+
+    context 'when feature disabled' do
+      it 'does nothing and returns 404' do
+        stub_feature_flags(elasticsearch_web_indexing: false)
+
+        expect(::Elastic::IndexProjectsService).not_to receive(:new)
+
+        post :enqueue_index
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+  end
+end

locale/gitlab.pot

@@ -306,6 +306,9 @@ msgstr ""
 msgid "(No changes)"
 msgstr ""
 
+msgid "(check progress)"
+msgstr ""
+
 msgid "(external source)"
 msgstr ""
 
@@ -4271,6 +4274,9 @@ msgstr ""
 msgid "Elasticsearch"
 msgstr ""
 
+msgid "Elasticsearch indexing started"
+msgstr ""
+
 msgid "Elasticsearch integration. Elasticsearch AWS IAM."
 msgstr ""
 
@@ -6606,6 +6612,9 @@ msgstr ""
 msgid "Incompatible options set!"
 msgstr ""
 
+msgid "Indexing"
+msgstr ""
+
 msgid "Indicates whether this runner can pick jobs without tags"
 msgstr ""
 
@@ -11534,6 +11543,9 @@ msgstr ""
 msgid "Start GitLab Ultimate trial"
 msgstr ""
 
+msgid "Start Indexing"
+msgstr ""
+
 msgid "Start Web Terminal"
 msgstr ""