NOTE: This approach has been deprecated for end-user code in favor of thread_mattr_accessor and friends. Please use that approach instead.
This module is used to encapsulate access to thread local variables.
Instead of polluting the thread locals namespace:
you define a class that extends this module:
and invoke the declared instance accessors as class methods. So
ActiveRecord::RuntimeRegistry.connection_handler = connection_handler
sets a connection handler local to the current thread, and
returns a connection handler local to the current thread.
This feature is accomplished by instantiating the class and storing the
instance as a thread local keyed by the class name. In the example above a
key “ActiveRecord::RuntimeRegistry” is stored in
Thread.current. The class methods proxy to said thread local
If the class has an initializer, it must accept no arguments.
# File activesupport/lib/active_support/per_thread_registry.rb, line 42 def self.extended(object) object.instance_variable_set "@per_thread_registry_key", object.name.freeze end
# File activesupport/lib/active_support/per_thread_registry.rb, line 46 def instance Thread.current[@per_thread_registry_key] ||= new end