Ensure secondary is enabled on failover

- Updated `geo:set_secondary_as_primary` to enabled
  the secondary node when run
- Migrated logic from task to helper so it could be
  tested

Relates to https://gitlab.com/gitlab-org/gitlab/issues/237896

ee/changelogs/unreleased/ensure_node_is_enabled.yml

+---
+title: Ensure secondary is enabled on failover
+merge_request: 39615
+author:
+type: fixed

ee/lib/gitlab/geo/geo_tasks.rb

@@ -17,6 +17,21 @@ module Gitlab
         end
       end
 
+      def set_secondary_as_primary
+        ActiveRecord::Base.transaction do
+          primary_node = GeoNode.primary_node
+          current_node = GeoNode.current_node
+
+          abort 'The primary is not set' unless primary_node
+          abort 'This is not a secondary node' unless current_node.secondary?
+
+          primary_node.destroy
+          current_node.update!(primary: true, enabled: true)
+
+          $stdout.puts "#{current_node.url} is now the primary Geo node".color(:green)
+        end
+      end
+
       def update_primary_geo_node_url
         node = Gitlab::Geo.primary_node
 

ee/lib/tasks/geo.rake

@@ -190,23 +190,7 @@ namespace :geo do
   task set_secondary_as_primary: :environment do
     abort GEO_LICENSE_ERROR_TEXT unless Gitlab::Geo.license_allows?
 
-    ActiveRecord::Base.transaction do
-      primary_node = GeoNode.primary_node
-
-      unless primary_node
-        abort 'The primary is not set'
-      end
-
-      primary_node.destroy
-
-      current_node = GeoNode.current_node
-
-      unless current_node.secondary?
-        abort 'This is not a secondary node'
-      end
-
-      current_node.update!(primary: true)
-    end
+    Gitlab::Geo::GeoTasks.set_secondary_as_primary
   end
 
   desc 'GitLab | Geo | Update Geo primary node URL'

ee/spec/lib/gitlab/geo/geo_tasks_spec.rb

@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 RSpec.describe Gitlab::Geo::GeoTasks do
+  include ::EE::GeoHelpers
+
   describe '.set_primary_geo_node' do
     before do
       allow(GeoNode).to receive(:current_node_name).and_return('https://primary.geo.example.com')
@@ -19,4 +21,48 @@ RSpec.describe Gitlab::Geo::GeoTasks do
       expect { subject.set_primary_geo_node }.to output(/Error saving Geo node:/).to_stdout
     end
   end
+
+  describe '.set_secondary_as_primary' do
+    let_it_be(:primary) { create(:geo_node, :primary) }
+    let(:secondary) { create(:geo_node) }
+
+    before do
+      stub_current_geo_node(secondary)
+      stub_current_node_name(secondary.name)
+    end
+
+    it 'aborts if the primary node is not set' do
+      primary.update_column(:primary, false)
+
+      expect(subject).to receive(:abort).with('The primary is not set').and_raise('aborted')
+
+      expect { subject.set_secondary_as_primary }.to raise_error('aborted')
+    end
+
+    it 'aborts if run on a node that is not a secondary' do
+      primary.update_column(:primary, false)
+      secondary.update!(primary: true)
+
+      expect(subject).to receive(:abort).with('This is not a secondary node').and_raise('aborted')
+
+      expect { subject.set_secondary_as_primary }.to raise_error('aborted')
+    end
+
+    it 'sets the secondary as the primary node' do
+      expect(subject).not_to receive(:abort)
+
+      expect { subject.set_secondary_as_primary }.to output(/#{secondary.url} is now the primary Geo node/).to_stdout
+      expect(secondary.reload.primary).to be true
+    end
+
+    it 'sets the secondary as the primary node, even if the secondary is disabled' do
+      secondary.update_column(:enabled, true)
+
+      expect(subject).not_to receive(:abort)
+
+      expect { subject.set_secondary_as_primary }.to output(/#{secondary.url} is now the primary Geo node/).to_stdout
+      expect(secondary.reload.primary).to be true
+      expect(secondary.reload.enabled?).to be true
+    end
+  end
 end