Source code for vstutils.tasks

from functools import wraps, WRAPPER_ASSIGNMENTS
from smtplib import SMTPException

from celery import Celery
from celery.signals import worker_process_init, worker_process_shutdown
from celery.exceptions import Reject
from import BaseTask
from celery.result import AsyncResult
from django.conf import settings
from django.apps import apps
from django.utils.module_loading import import_string

from .utils import send_template_email_handler, Lock, translate as _

celery_app: Celery = import_string(
    settings.WORKER_OPTIONS['app'].replace(':', '.')
notificator = None

def get_notificator():
    return apps.get_app_config('vstutils_api').module.notificator_class([])

def init_notificator(*_, **__):
    # pylint: disable=global-statement
    global notificator
    notificator = get_notificator()  # nocv

def destruct_notificator(*_, **__):
    # pylint: disable=global-statement
    global notificator
    if notificator is not None:  # nocv
        del notificator

class TaskMeta(type):
    def __new__(mcs, name, bases, attrs, uniq=None):
        task_class = super(TaskMeta, mcs).__new__(mcs, name, bases, attrs) = mcs.get_notificator_decorator(

        if uniq:
   = mcs.get_unique_decorator(
            task_class.apply_async = mcs.get_unique_decorator(task_class.apply_async, is_apply=True)
        elif hasattr(, '__uniq_wrapped__') and uniq is not None:
            task_class.apply_async = task_class.apply_async.__uniq_wrapped__

        return task_class

    def get_notificator_decorator(func):
        if getattr(func, '__notify_wrapped__', False):
            return func

        @wraps(func, assigned=WRAPPER_ASSIGNMENTS+('__notify_wrapped__',))
        def wrapper(self, *args, **kwargs):
            with notificator or get_notificator() as notifier:
                self.__notifier__ = notifier
                result = func(self, *args, **kwargs)
            self.__notifier__ = None
            return result

        wrapper.__notify_wrapped__ = True
        return wrapper

    def get_unique_decorator(func, is_apply=False):
        if getattr(func, '__uniq_wrapped__', False):
            return func

        @wraps(func, assigned=WRAPPER_ASSIGNMENTS+('__uniq_wrapped__',))
        def wrapper(self, *args, **kwargs):
            # pylint: disable=protected-access
            if not is_apply and self._get_app().conf.task_always_eager:
                return func(self, *args, **kwargs)
                with Lock(
                    err_msg=_("This task is currently performed by another worker.")
                    return func(self, *args, **kwargs)
            except Lock.AcquireLockException as err:
                raise Reject(str(err), requeue=False) from err

        wrapper.__uniq_wrapped__ = func
        return wrapper

[docs]class TaskClass(BaseTask, metaclass=TaskMeta): """ Wrapper for Celery BaseTask class. Usage is same as Celery standard class, but you can execute task without creating instance with :meth:`` method. Example: .. sourcecode:: python from vstutils.environment import get_celery_app from vstutils.tasks import TaskClass app = get_celery_app() class Foo(TaskClass): def run(*args, **kwargs): return 'Foo task has been executed' app.register_task(Foo()) Now you can call your task with various methods: - by executing ``*args, **kwargs)`` - get registered task instance like that - app.tasks[''] Also you can make your registered task periodic, by adding it to CELERY_BEAT_SCHEDULE in .. sourcecode:: python CELERY_BEAT_SCHEDULE = { 'foo-execute-every-month': { 'task': '', 'schedule': crontab(day_of_month=1), }, } """ # pylint: disable=abstract-method @property def name(self): """ property for proper Celery task execution, needed for :meth:`` method to work """ return self.__name__ @property def __name__(self): return f'{self.__class__.__module__}.{self.__class__.__name__}'
[docs] @classmethod def do(cls, *args, **kwargs) -> AsyncResult: """ Method which send signal to celery for start remote task execution. All arguments will passed to the task :meth:`` method. """ return cls().delay(*args, **kwargs)
class SendEmailMessage(TaskClass): """ Task for sending bulk emails, all args and kwargs are passed to :func:`vstutils.utils.send_template_email_handler`. Usually you don't need to call this manually, this is called by :func:`vstutils.utils.send_template_email`. """ ignore_result = True def run(self, *args, **kwargs): try: send_template_email_handler(*args, **kwargs) except SMTPException as exc: raise self.retry( exc=exc, max_retries=settings.SEND_EMAIL_RETRIES, countdown=settings.SEND_MESSAGE_RETRY_DELAY ) celery_app.register_task(SendEmailMessage())