Create empty index if none found when Elasticsearch indexing enabled

If Elasticsearch indexing is enabled and an existing index does not
exist, a new empty index will be created. The UI messaging and docs
were updated with the new behaviors.

doc/integration/elasticsearch.md

@@ -178,22 +178,11 @@ To enable Advanced Search, you need to have admin access to GitLab:
    [license](../user/admin_area/license.md).
 
 1. Configure the [Advanced Search settings](#advanced-search-configuration) for
-   your Elasticsearch cluster. Do not enable **Elasticsearch indexing** or
-   **Search with Elasticsearch enabled** yet.
-1. Click **Save changes** for the changes to take effect.
-1. Before enabling **Elasticsearch indexing** you need to create an index by
-   running the Rake task:
-
-   ```shell
-   # Omnibus installations
-   sudo gitlab-rake gitlab:elastic:create_empty_index
-
-   # Installations from source
-   bundle exec rake gitlab:elastic:create_empty_index RAILS_ENV=production
-   ```
-
-1. Now enable `Elasticsearch indexing` in **Admin Area > Settings >
-   General > Advanced Search** and click **Save changes**.
+   your Elasticsearch cluster. Do not enable **Search with Elasticsearch enabled** 
+   yet.
+1. Now enable **Elasticsearch indexing** in **Admin Area > Settings >
+   General > Advanced Search** and click **Save changes**. This will create
+   an empty index if one does not already exist.
 1. Click **Index all projects**.
 1. Click **Check progress** in the confirmation message to see the status of
    the background jobs.
@@ -217,7 +206,7 @@ The following Elasticsearch settings are available:
 
 | Parameter                                             | Description |
 |-------------------------------------------------------|-------------|
-| `Elasticsearch indexing`                              | Enables or disables Elasticsearch indexing. You may want to enable indexing but disable search in order to give the index time to be fully completed, for example. Also, keep in mind that this option doesn't have any impact on existing data, this only enables/disables the background indexer which tracks data changes and ensures new data is indexed. |
+| `Elasticsearch indexing`                              | Enables or disables Elasticsearch indexing and creates an empty index if one does not already exist. You may want to enable indexing but disable search in order to give the index time to be fully completed, for example. Also, keep in mind that this option doesn't have any impact on existing data, this only enables/disables the background indexer which tracks data changes and ensures new data is indexed. |
 | `Pause Elasticsearch indexing`                        | Enables or disables temporary indexing pause. This is useful for cluster migration/reindexing. All changes are still tracked, but they are not committed to the Elasticsearch index until unpaused. |
 | `Search with Elasticsearch enabled`                   | Enables or disables using Elasticsearch in search. |
 | `URL`                                                 | The URL to use for connecting to Elasticsearch. Use a comma-separated list to support clustering (e.g., `http://host1, https://host2:9200`). If your Elasticsearch instance is password protected, pass the `username:password` in the URL (e.g., `http://<username>:<password>@<elastic_host>:9200/`). |

ee/app/services/ee/application_settings/update_service.rb

@@ -8,8 +8,6 @@ module EE
 
       override :execute
       def execute
-        return false if prevent_elasticsearch_indexing_update?
-
         # Repository size limit comes as MB from the view
         limit = params.delete(:repository_size_limit)
         application_setting.repository_size_limit = ::Gitlab::Utils.try_megabytes_to_bytes(limit) if limit
@@ -18,6 +16,7 @@ module EE
         elasticsearch_project_ids = params.delete(:elasticsearch_project_ids)
 
         if result = super
+          find_or_create_index
           update_elasticsearch_containers(ElasticsearchIndexedNamespace, elasticsearch_namespace_ids)
           update_elasticsearch_containers(ElasticsearchIndexedProject, elasticsearch_project_ids)
         end
@@ -43,10 +42,13 @@ module EE
 
       private
 
-      def prevent_elasticsearch_indexing_update?
-        !application_setting.elasticsearch_indexing &&
-          ::Gitlab::Utils.to_boolean(params[:elasticsearch_indexing]) &&
-          !::Gitlab::Elastic::Helper.default.index_exists?
+      def find_or_create_index
+        # The order of checks is important. We should not attempt to create a new index
+        # unless elasticsearch_indexing is enabled
+        return unless application_setting.elasticsearch_indexing
+        return if ::Gitlab::Elastic::Helper.default.index_exists?
+
+        ::Gitlab::Elastic::Helper.default.create_empty_index
       end
     end
   end

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

@@ -26,7 +26,7 @@
                 Elasticsearch indexing
               - unless Gitlab::CurrentSettings.elasticsearch_indexing?
                 .form-text.text-muted
-                  = _('Please create an index before enabling indexing')
+                  = _('An empty index will be created if one does not already exist')
               - if Gitlab::CurrentSettings.elasticsearch_indexing?
                 .form-text
                   = link_to _('Index all projects'), admin_elasticsearch_enqueue_index_path,

ee/changelogs/unreleased/239270-remove-the-need-to-run-rake-tasks-to-create-index-when-enabling.yml

+---
+title: Find or create index when Elasticsearch indexing enabled
+merge_request: 43912
+author:
+type: changed

ee/spec/services/application_settings/update_service_spec.rb

@@ -34,26 +34,26 @@ RSpec.describe ApplicationSettings::UpdateService do
       end
     end
 
-    context 'index dependent' do
-      using RSpec::Parameterized::TableSyntax
-
-      where(:index_exists, :indexing_enabled, :input_value, :result) do
-        false  | false | true | false
-        false  | true  | true | true
-        true   | false | true | true
-        true   | true  | true | true
-      end
+    context 'elasticsearch_indexing update' do
+      context 'index creation' do
+        let(:opts) { { elasticsearch_indexing: true } }
+
+        context 'when index exists' do
+          it 'skips creating a new index' do
+            expect(Gitlab::Elastic::Helper.default).to(receive(:index_exists?)).and_return(true)
+            expect(Gitlab::Elastic::Helper.default).not_to(receive(:create_empty_index))
 
-      with_them do
-        before do
-          allow(Gitlab::Elastic::Helper.default).to(receive(:index_exists?)).and_return(index_exists)
-          allow(service.application_setting).to(receive(:elasticsearch_indexing)).and_return(indexing_enabled)
+            service.execute
+          end
         end
 
-        let(:opts) { { elasticsearch_indexing: input_value } }
+        context 'when index does not exist' do
+          it 'creates a new index' do
+            expect(Gitlab::Elastic::Helper.default).to(receive(:index_exists?)).and_return(false)
+            expect(Gitlab::Elastic::Helper.default).to(receive(:create_empty_index))
 
-        it 'returns correct result' do
-          expect(service.execute).to be(result)
+            service.execute
+          end
         end
       end
     end

locale/gitlab.pot

@@ -2683,6 +2683,9 @@ msgstr ""
 msgid "An empty GitLab User field will add the FogBugz user's full name (e.g. \"By John Smith\") in the description of all issues and comments. It will also associate and/or assign these issues and comments with the project creator."
 msgstr ""
 
+msgid "An empty index will be created if one does not already exist"
+msgstr ""
+
 msgid "An error has occurred"
 msgstr ""