Attachment 10338 Details for Bug 51126

Proof of concept for lazy UCR

lazy-ucr.py (text/x-python), 2.02 KB, created by Philipp Hahn on 2020-04-21 11:21 CEST

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Creator: Philipp Hahn

Created: 2020-04-21 11:21 CEST

Size: 2.02 KB

patch

obsolete

>#!/usr/bin/python2
># https://stevenloria.com/lazy-properties/
>
>from __future__ import print_function
>from threading import Lock
>from functools import partial
>from univention.config_registry import ConfigRegistry
>import inspect
>
>
>def lazy(cls):
>    """
>    Copy methods and constants from UCR and wrap for lazy loading.
>    """
>    for name, value in inspect.getmembers(ConfigRegistry):
>        if hasattr(cls, name):
>            continue
>
>        if callable(value):
>            def wrap(__meth, *args, **kwargs):
>                if not isinstance(cls._instance, ConfigRegistry):
>                    with cls._lock:
>                        print("UCR.init")
>                        ucr = ConfigRegistry()
>                        ucr.load()
>                        if not isinstance(cls._instance, ConfigRegistry):
>                            cls._instance = ucr
>                            # undo proxying
>                            for name2, value2 in inspect.getmembers(ConfigRegistry, callable):
>                                if isinstance(getattr(cls, name2), partial):
>                                    print("UNPROXY", name2, getattr(cls, name2), value2)
>                                    setattr(cls, name2, partial(value2, cls._instance))
>
>                assert isinstance(cls._instance, ConfigRegistry)
>
>                print("PROXY", __meth, *args, **kwargs)
>                return __meth(cls._instance, *args, **kwargs)
>
>            setattr(cls, name, partial(wrap, value))
>        else:
>            setattr(cls, name, value)
>
>    return cls
>
>
>@lazy
>class LazyUcr(object):
>    _instance = None
>    _lock = Lock()
>
>    def __new__(cls):
>        """Singleton"""
>        print("Lazy.init")
>        if cls._instance is None:
>            with cls._lock:
>                if cls._instance is None:
>                    cls._instance = super(LazyUcr, cls).__new__(cls)
>        return cls._instance
>
>
>ucr = LazyUcr()  # type: ConfigRegistry
>print()
>print(ucr.PREFIX)
>print()
>print(ucr.values()[:2])
>print()
>print(ucr["server/role"])
>print(ucr["server/role"])

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Attachments on bug 51126: 10338