vcsserver/lib/statsd_client.py

from vcsserver.lib._vendor.statsd import client_from_config


class StatsdClientNotInitialised(Exception):
    pass


class _Singleton(type):
    """A metaclass that creates a Singleton base class when called."""

    _instances = {}

    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(_Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]


class Singleton(_Singleton("SingletonMeta", (object,), {})):
    pass


class StatsdClientClass(Singleton):
    setup_run = False
    statsd_client = None
    statsd = None
    strict_mode_init = False

    def __getattribute__(self, name):

        if name.startswith("statsd"):
            if self.setup_run:
                return super(StatsdClientClass, self).__getattribute__(name)
            else:
                if self.strict_mode_init:
                    raise StatsdClientNotInitialised(f"requested key was {name}")
                return None

        return super(StatsdClientClass, self).__getattribute__(name)

    def setup(self, settings):
        """
        Initialize the client
        """
        strict_init_mode = settings.pop('statsd_strict_init', False)

        statsd = client_from_config(settings)
        self.statsd = statsd
        self.statsd_client = statsd
        self.setup_run = True


StatsdClient = StatsdClientClass()