singleton-meta 0.0.2

create perfect singletons meta

singleton_meta

Features

1. perfect singleton (maybe thread safe!)
2. collect all instances

License

See the LICENSE file for license rights and limitations (MIT).

Release history

See the HISTORY.md file for release history.

Installation

pip install singleton-meta

Import

from singleton_meta import *

GUIDE

See tests and source for other examples.

1. Use simple nesting (common)

from singleton_meta import *

class MySingleton(Singleton):
    pass

class MySingleton2(Singleton):
    pass

2. access to created instances

from singleton_meta import *

    class Victim1(Singleton):
        attr = 1

    class Victim2(Singleton):
        attr = 2

    assert Singleton._SINGLETONS == []
    Victim1()
    assert Singleton._SINGLETONS == [Victim1(), ]
    Victim2()
    assert Singleton._SINGLETONS == [Victim1(), Victim2(), ]

3. Use meta

from singleton_meta import *

class MySingleton(metaclass=SingletonMeta):
    pass

4. NOTICE: all your Singletons must be only last classes!

don't use nesting from any Your Singletons!

from singleton_meta import *

class MySingleton(Singleton):   # OK
    pass

class MySingleton2(MySingleton):    # WRONG
    pass