pydefer

pydefer aims to emulate the same experience you get from using Golang's defer keyword. pydefer allows you to execute a function around a given wrapped function after the wrapped function has executed.

Installing

$ pip install pydefer

or

$ pipenv install pydefer

Usage

Here's a basic example of using defer to print the sequence of numbers between [6,10] after print_sequence is called (which calls the sequence of numbers between [1,5]).

>>> from pydefer.defer import defer
>>>
>>> @defer(print,6,7,8,9,10)
... def print_sequence():
...     print(1,2,3,4,5)
...
>>> print_seqeuence()
1 2 3 4 5
6 7 8 9 10

Some more complex use cases of pydefer is to be able to close files and not have to worry about closing them yourself in the actual function. Another use case is possibly session management for a web app after a user visits different routes.

Here's the aforementioned more complex example of deferring of closing a file.

from python.defer import defer

@defer(open('employee_data.txt','r').close)
def update_employee(e_id):
    f = open('employee_data.txt','w')
    # DO STUFF TO FILE

    f.write(e_id.salary)

    # DO MORE STUFF LATER ON

In the above example, you do not need to manage the file anywhere inside the function as the defer function wrapper will close that file for you after the update_employee function has finished.