Disable multi-db for SQLite

lib/rails_ext/active_record_replica_support.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+# Adds a helper method to check if replica database connections are configured
+# and automatically configures read/write splitting when replicas are available.
+#
+# Usage:
+#   class ApplicationRecord < ActiveRecord::Base
+#     configure_replica_connections
+#   end
+module ActiveRecordReplicaSupport
+  extend ActiveSupport::Concern
+
+  class_methods do
+    # Automatically configures connects_to for read/write splitting if a replica
+    # database is configured for the current environment. This is a no-op if no
+    # replica configuration exists.
+    #
+    # Example:
+    #   class ApplicationRecord < ActiveRecord::Base
+    #     configure_replica_connections
+    #   end
+    def configure_replica_connections
+      if replica_configured?
+        connects_to database: { writing: :primary, reading: :replica }
+      end
+    end
+
+    # Returns true if a replica database configuration exists for the current
+    # environment. This allows different database adapters to opt in or out of
+    # read/write splitting based on their database.yml configuration.
+    #
+    # Example:
+    #   ApplicationRecord.replica_configured? # => true for MySQL, false for SQLite
+    def replica_configured?
+      configurations.find_db_config("replica").present?
+    end
+  end
+end
+
+ActiveRecord::Base.include ActiveRecordReplicaSupport