1 files changed, 26 insertions, 0 deletions
diff --git a/config/initializers/00_connection_logger.rb b/config/initializers/00_connection_logger.rb
new file mode 100644
index 00000000000..9f03d13f95f
--- /dev/null
+++ b/config/initializers/00_connection_logger.rb
@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module NewConnectionLogger
+  extend ActiveSupport::Concern
+
+  prepended do |base|
+    base.class_attribute :warn_on_new_connection, default: false
+  end
+
+  class_methods do
+    def new_client(...)
+      if warn_on_new_connection && !ENV['SKIP_LOG_INITIALIZER_CONNECTIONS']
+        cleaned_caller = Gitlab::BacktraceCleaner.clean_backtrace(caller)
+        message = "Database connection should not be called during initializers. Read more at https://docs.gitlab.com/ee/development/rails_initializers.html#database-connections-in-initializers"
+
+        ActiveSupport::Deprecation.warn(message, cleaned_caller)
+
+        warn caller if ENV['DEBUG_INITIALIZER_CONNECTIONS']
+      end
+
+      super
+    end
+  end
+end
+
+ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.prepend(NewConnectionLogger)