Usage ¶

Topics

By extending the Decorator class you can create simple decorators. Implement the before() and/or after() methods to perform actions before or after execution of the decorated item. The before() method can access the arguments of the decorated item by changing the args and kwargs attributes. The after() method can access or change the result using the result attribute. The exception() method can be used for do something with an Exception that has been raised. In all three methods the fqn and func attributes are available.

Simple decorator ¶

Create a simple decorator:

import fqn_decorators
import time

class time_it(fqn_decorators.Decorator):

    def before(self):
        self.start = time.time()

    def after(self):
        duration = time.time() - self.start
        print("{0} took {1} seconds".format(self.fqn, duration))


@time_it
def my_function():
    time.sleep(1)

>>>my_function()
__main__.my_function took 1.00293397903 seconds

Decorator with arguments ¶

It is also very easy to create a decorator with arguments.

Note

It is not possible to create decorators with non-keyworded arguments. To create a decorator that supports non-keyworded arguments see the Advanced Usage section.

Example:

import fqn_decorators
import time

class threshold(fqn_decorators.Decorator):

    def before(self):
        self.start = time.time()

    def after(self):
        duration = time.time() - self.start
        treshold = self.params.get('threshold')
        if threshold and duration > threshold:
            raise Exception('Execution took longer than the threshold')


@threshold(threshold=2)
def my_function():
    time.sleep(3)

>>> my_function()
Exception: Execution took longer than the threshold

Usage¶

Introduction¶

Simple decorator¶

Decorator with arguments¶

Usage ¶

Introduction ¶

Simple decorator ¶

Decorator with arguments ¶