A Singleton python project

By CenturyBoys

Did you need help? Call meeseeks from a single box from anywhere

This is meeseeks a single class to do singletons. In the core meeseeks is a class decorator that allows you to have a global singleton scope or a specialized one, some configurations can be used to give more flexibility to your code.

Scopes

Each class with his decorator has a specialized scope, that is otherwise you create meeseeks object (OnlyOne) and this object will have your configuration and singletons

Specialized

import meeseeks

@meeseeks.OnlyOne()
class A:
    def __int__(self, a):
        pass

a1a = A(10)
a1b = A(10)
a1c = A(20)

assert a1a == a1b == a1c

or

import meeseeks

only_one = meeseeks.OnlyOne()

@only_one
class A:
    def __int__(self, a):
        pass

a1a = A(10)
a1b = A(10)
a1c = A(20)

assert a1a == a1b == a1c

On this example we register the class reference in the meeseeks class instance scope

Configuration

We provide two configuration options:

• tll: int (time to live) in seconds. Setting a value greater than 0, the singleton reference will have a time to live in seconds (default 0). Obs: the expired time validation will be made only when you create a new instance of the registered class ie your object will still be in memory
• by_args_hash: bool ( a hash will be made of all args and kwargs ). Setting True, a singleton reference will be created for each arg + kwargs hash (default False). Obs: The kwargs`s order doesn't have influence

TTL

import meeseeks
import time

@meeseeks.OnlyOne(ttl=1)
class A:
    def __int__(self, *args, **kwargs):
        pass

a1a = A(1, var_a="a")
a1b = A(1, var_a="a")

time.sleep(1)

a1c = A(1, var_a="a")

assert a1a == a1b
assert a1b != a1c

In this example, we set the ttl to 1 second and validate if the first two calls result in the same object and after 1 second we validate if the object is different from the first two

BY_ARGS_HASH

import meeseeks
import time

@meeseeks.OnlyOne(by_args_hash=True)
class A:
    def __int__(self, *args, **kwargs):
        pass

a1a = A(1, var_a="a", var_b="b")
a1b = A(1, var_b="b", var_a="a")
a1c = A(10, var_b="b", var_a="a")



assert a1a == a1b
assert a1c != a1b

In this example, we set by_args_hash variable to True and validate if the first two calls result in the same object despite the kwargs order being different. The last validation shows us that different args and kwargs result in different objects.