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Redis – How to use multiprocess in django command?

I’m tring to use ProcessPoolExecutor in django command to get some results at same time. And I tried with below codes to get it

# main codes


import json
import time
import datetime
from concurrent.futures import ThreadPoolExecutor, ProcessPoolExecutor


from redis import Redis
from django.conf import settings
from django.core.management.base import BaseCommand
from thrift.transport import TSocket, TTransport
from thrift.protocol import TBinaryProtocol

from utils.cache import pool
from services.analysis.thrift.Analysis import Client, Dashparam
from api.analysis.models import MDashBoard


redis_con = Redis(connection_pool=pool)

class AnalysisThriftService(object):

    def __init__(self):
        ...

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.transport.close()



class Command(BaseCommand):
    help = 'python manage.py --settings "xxx"'

    def add_arguments(self, parser):
        parser.add_argument('--dashboard_id', type=int, help="ID")

    @staticmethod
    def _handle_with_thrift(dashboard_id):
        try:
            print(dashboard_id)
            with AnalysisThriftService() as thrift_server:
                dashboard_result = ...
                
        except:
            import traceback
            traceback.print_exc()

    def handle(self, *args, **options):
        dashboard_id = options["dashboard_id"]
        if dashboard_id is None:
            dashboard_tables = [dashboard.id for dashboard in MDashBoard.objects.all()]
            with ProcessPoolExecutor(max_workers=5) as executor:
                executor.map(Command._handle_with_thrift, dashboard_tables)

        else:
            ...

But I always get error like

Process Process-5:
Process Process-2:
Traceback (most recent call last):
  File "D:python3libmultiprocessingprocess.py", line 258, in _bootstrap
    self.run()
  File "D:python3libmultiprocessingprocess.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "D:python3libconcurrentfuturesprocess.py", line 169, in _process_worker
    call_item = call_queue.get(block=True)
  File "D:python3libmultiprocessingqueues.py", line 113, in get
    return _ForkingPickler.loads(res)
  File "C:UsersDomobDesktopdevmyapianalysismanagementcommandsdashboard_schedule_task.py", line 15, in <modu
le>
    from api.analysis.models import MDashBoard
  File "C:UsersDomobDesktopdevmyapianalysismodels.py", line 4, in <module>
    from utils.models import BasicModel, StaticCharField
  File "C:UsersDomobDesktopdevmyapiutilsmodels.py", line 9, in <module>
    class BasicModel(models.Model):
  File "C:UsersDomobDesktopdevvenv_myapilibsite-packagesdjangodbmodelsbase.py", line 103, in __new__
    app_config = apps.get_containing_app_config(module)
  File "C:UsersDomobDesktopdevvenv_myapilibsite-packagesdjangoappsregistry.py", line 252, in get_containing_ap
p_config
    self.check_apps_ready()
  File "C:UsersDomobDesktopdevvenv_myapilibsite-packagesdjangoappsregistry.py", line 135, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

How can I get the expected results.

Great thanks.

Tags:

2

Answers


  1. 0

    You’ll need to set up Django for the subprocesses in the subprocess initializer function.

    def subprocess_setup():
    django.setup()
    # Could do other things here

# ...

with ProcessPoolExecutor(max_workers=5, initializer=subprocess_setup) as executor:
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  2. 0

    Got the same issue but solved it differently as suggested by this thread.

    I had to explicitly pass the context to the ProcessPoolExecutor in order to get things right.
    The code would look something like this

    import multiprocessing

fork_context = multiprocessing.get_context('fork')
with ProcessPoolExecutor(max_workers=5, mp_context=fork_context) as executor:
...
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