wrapt

A Python module for decorators, wrappers and monkey patching.

Overview

The aim of the wrapt module is to provide a transparent object proxy for Python, which can be used as the basis for the construction of function wrappers and decorator functions.

An easy to use decorator factory is provided to make it simple to create your own decorators that will behave correctly in any situation they may be used.

import wrapt

@wrapt.decorator
def pass_through(wrapped, instance, args, kwargs):
    return wrapped(*args, **kwargs)

@pass_through
def function():
    pass

In addition to the support for creating object proxies, function wrappers and decorators, the module also provides a post import hook mechanism and other utilities useful in performing monkey patching of code.

The wrapt module focuses very much on correctness. It therefore goes way beyond existing mechanisms such as functools.wraps() to ensure that decorators preserve introspectability, signatures, type checking abilities etc. The decorators that can be constructed using this module will work in far more scenarios than typical decorators and provide more predictable and consistent behaviour.

To ensure that the overhead is as minimal as possible, a C extension module is used for performance critical components. An automatic fallback to a pure Python implementation is also provided where a target system does not have a compiler to allow the C extension to be compiled.

Presentations

Conference presentations related to the wrapt module:

Blog Posts

Blog posts related to the wrapt module:

Installation

The wrapt module is available from PyPi at:

and can be installed using pip.

pip install wrapt

Source Code

Full source code for the wrapt module, including documentation files and unit tests, can be obtained from github.