Create idea of read-only databasetc-geo-read-only-idea

In GitLab EE, a GitLab instance can be read-only (e.g. when it's a Geo
secondary node). But in GitLab CE it also might be useful to have the
"read-only" idea around. So port it back to GitLab CE.

Also having the principle of read-only in GitLab CE would hopefully
lead to less errors introduced, doing write operations when there
aren't allowed for read-only calls.

Closes gitlab-org/gitlab-ce#37534.

1 files changed, 18 insertions, 0 deletions

diff --git a/app/controllers/projects/lfs_api_controller.rb b/app/controllers/projects/lfs_api_controller.rb
index 1b0d3aab3fa..536f908d2c5 100644
--- a/app/controllers/projects/lfs_api_controller.rb
+++ b/app/controllers/projects/lfs_api_controller.rb
@@ -2,6 +2,7 @@ class Projects::LfsApiController < Projects::GitHttpClientController
   include LfsRequest
 
   skip_before_action :lfs_check_access!, only: [:deprecated]
+  before_action :lfs_check_batch_operation!, only: [:batch]
 
   def batch
     unless objects.present?
@@ -90,4 +91,21 @@ class Projects::LfsApiController < Projects::GitHttpClientController
       }
     }
   end
+
+  def lfs_check_batch_operation!
+    if upload_request? && Gitlab::Database.read_only?
+      render(
+        json: {
+          message: lfs_read_only_message
+        },
+        content_type: 'application/vnd.git-lfs+json',
+        status: 403
+      )
+    end
+  end
+
+  # Overridden in EE
+  def lfs_read_only_message
+    _('You cannot write to this read-only GitLab instance.')
+  end
 end