app01/
    __init__.py
    models.py
    management/
        __init__.py
        commands/
            __init__.py
            _private.py # 以下劃線開(kāi)頭文件不能用作管理命令
            my_commands.py # 這個(gè)就是自定義的管理命令腳本，文件名即為命令名
    tests.py
    views.py

 from django.core.management.base import BaseCommand
 
 class Command(BaseCommand):
     # 幫助文本, 一般備注命令的用途及如何使用。
     help = 'Some help texts'
 
     # 處理命令行參數(shù)，可選
     def add_arguments(self, parser):
        pass
 
     # 核心業(yè)務(wù)邏輯
     def handle(self, *args, **options):
         pass

 from django.core.management.base import BaseCommand
 
 class Command(BaseCommand):
    # 幫助文本, 一般備注命令的用途及如何使用。
    help = "Print Hello World!"
 
    # 核心業(yè)務(wù)邏輯
    def handle(self, *args, **options):
        self.stdout.write('Hello World!')

 from django.core.management.base import BaseCommand
 
 class Command(BaseCommand):
    # 幫助文本, 一般備注命令的用途及如何使用。
    help = "Print Hello World!"
 
    # 給命令添加一個(gè)名為name的參數(shù)
    def add_arguments(self, parser):
        parser.add_argument('name')
 
    # 核心業(yè)務(wù)邏輯，通過(guò)options字典接收name參數(shù)值，拼接字符串后輸出
    def handle(self, *args, **options):
        msg = 'Hello World ! '+ options['name']
        self.stdout.write(msg)

 # app/management/commands/wait_for_db.py
 
 import time
 from django.db import connections
 from django.db.utils import OperationalError
 from django.core.management import BaseCommand
 
 
 class Command(BaseCommand):
     help = 'Run data migrations until db is available.'
 
     def handle(self, *args, **options):
         self.stdout.write('Waiting for database...')
         db_conn = None
         while not db_conn:
             try:
                 # 嘗試連接
                 db_conn = connections['default']
             except OperationalError:
                 # 連接失敗，就等待1秒鐘
                 self.stdout.write('Database unavailable, waiting 1 second...')
                 time.sleep(1)
 
         self.stdout.write(self.style.SUCCESS('Database available!'))

 # app/management/commands/mail_admin.py
 
 #-*- coding:utf-8 -*-
 from datetime import timedelta, time, datetime
 from django.core.mail import mail_admins
 from django.core.management import BaseCommand
 from django.utils import timezone
 from django.contrib.auth import get_user_model
 
 User = get_user_model()
 
 today = timezone.now()
 yesterday = today - timedelta(1)
 
 
 class Command(BaseCommand):
     help = "Send The Daily Count of New Users to Admins"
 
     def handle(self, *args, **options):
         # 獲取過(guò)去一天注冊(cè)用戶數(shù)量
         user_count =User.objects.filter(date_joined__range=(yesterday, today)).count()
         
         # 當(dāng)注冊(cè)用戶數(shù)量多余1個(gè)，才發(fā)送郵件給管理員
         if user_count >= 1:
             message = "You have got {} user(s) in the past 24 hours".format(user_count)
 
             subject = (
                 f"New user count for {today.strftime('%Y-%m-%d')}: {user_count}"
            )
 
             mail_admins(subject=subject, message=message, html_message=None)
 
             self.stdout.write("E-mail was sent.")
         else:
             self.stdout.write("No new users today.")

 EMAIL_BACKEND = "django.core.mail.backends.console.EmailBackend"
 DEFAULT_FROM_EMAIL = "noreply@example.com"
 ADMINS = [("大江狗", "yunbo.shi@example.com"), ]

 # app/tasks.py, 可以任一app目錄下新建task
 from celery import shared_task
 from django.core.management import call_command
 
 @shared_task
 def mail_admin():
     call_command("mail_admin", )