Django项目启动遇AppRegistryNotReady及populate()非可重入问题求助

项目结构 #

watcher 
    |-config    
        |-__init__.py
        |- asgi.py
        |- config.ini
        |- settings.py
        |- urls.py
        |- wsgi.py
    |-tower
        |-__init__.py
        |-admin.py
        |-apps.py
        |-models.py
        |-tests.py
        |-views.py
    |-manage.py

原始 tower/apps.py 代码 #

# import os
# os.environ.setdefault("DJANGO_SETTINGS_MODULE", "watcher.settings")
# import django
# django.setup()
from .models import CryptoTicker, CryptoTrade, CryptoOrderbookMain, CryptoOrderbookSub


class TowerConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'tower'

    def ready(self):
        print("Hello")
        socket = SocketClient()
        socket.start()

class SocketClient(threading.Thread):
    def __init__(self):
        super().__init__()
        self.url = "wss://api.upbit.com/websocket/v1"

        
        self.ws = websocket.WebSocketApp(
            url=self.url,
            header=headers,
            on_message=self.on_message,
            on_error=self.on_error,
            on_close=self.on_close,
            on_open=self.on_open
        )

        self.step = 0

    def run(self):
        while True:
            self.ws.run_forever()

    def on_message(self, ws, message):
        data = message.decode('utf-8')
        self.process(data)
        if self.step < 0:
            print("----- ----- ----- ----- ----- ----- -----")
            print()
            print(data)
            print()
            print("----- ----- ----- ----- ----- ----- -----")
            self.step += 1

    def on_error(self, ws, err):
        print(err)

    def on_close(self, ws, status_code, msg):
        print("closed!")

    def on_open(self, ws):
        print("connected!")
        ws.send('[{"ticket":"siren1"}, {"type":"ticker","codes":["KRW-BTC", "KRW-SOL"]}, {"type":"trade","codes":["KRW-BTC", "KRW-SOL"]}, {"type":"orderbook","codes":["KRW-BTC", "KRW-SOL"]}, {"format": "DEFAULT"}]')

    def process(self, data):
        pass

执行命令后的错误 #

执行命令 python manage.py runserver --noreload 0.0.0.0:8000 后出现：

File "D:\git\crypto-siren\venv\Lib\site-packages\django\apps\registry.py", line 138, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.

尝试添加手动初始化代码后出现新错误：

import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "watcher.settings")
import django
django.setup()

File "D:\git\crypto-siren\watcher\tower\apps.py", line 15, in <module>
    django.setup()
File "D:\git\crypto-siren\venv\Lib\site-packages\django\__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
File "D:\git\crypto-siren\venv\Lib\site-packages\django\apps\registry.py", line 83, in populate
    raise RuntimeError("populate() isn't reentrant")
RuntimeError: populate() isn't reentrant

解决方法 #

核心原因 #

模块级别直接导入模型时，Django的应用注册表还未完成加载，触发AppRegistryNotReady错误；手动调用django.setup()会导致Django重复初始化应用注册表，引发populate() isn't reentrant错误。

具体修正步骤 #

1. 移除模块级别的模型导入
   删除apps.py顶部的from .models import ...语句，不要在模块初始化阶段导入任何Django模型。

2. 在需要使用模型的函数内部导入
   把模型导入移到实际使用的方法中（比如process方法），此时Django应用已经加载完成：

   def process(self, data):
       from .models import CryptoTicker, CryptoTrade, CryptoOrderbookMain, CryptoOrderbookSub
       # 后续处理逻辑
   

3. 补充缺失的依赖导入
   原代码中缺少threading和websocket的导入，以及headers的定义，需要补上：

   import threading
   import websocket
   
   # 定义headers（根据实际需求调整）
   headers = {"Content-Type": "application/json"}
   

4. 修正后的完整代码

   import threading
   import websocket
   
   headers = {"Content-Type": "application/json"}
   
   class TowerConfig(AppConfig):
       default_auto_field = 'django.db.models.BigAutoField'
       name = 'tower'
   
       def ready(self):
           print("Hello")
           socket = SocketClient()
           socket.start()
   
   class SocketClient(threading.Thread):
       def __init__(self):
           super().__init__()
           self.url = "wss://api.upbit.com/websocket/v1"
   
           self.ws = websocket.WebSocketApp(
               url=self.url,
               header=headers,
               on_message=self.on_message,
               on_error=self.on_error,
               on_close=self.on_close,
               on_open=self.on_open
           )
   
           self.step = 0
   
       def run(self):
           while True:
               self.ws.run_forever()
   
       def on_message(self, ws, message):
           data = message.decode('utf-8')
           self.process(data)
           if self.step < 0:
               print("----- ----- ----- ----- ----- ----- -----")
               print()
               print(data)
               print()
               print("----- ----- ----- ----- ----- ----- -----")
               self.step += 1
   
       def on_error(self, ws, err):
           print(err)
   
       def on_close(self, ws, status_code, msg):
           print("closed!")
   
       def on_open(self, ws):
           print("connected!")
           ws.send('[{"ticket":"siren1"}, {"type":"ticker","codes":["KRW-BTC", "KRW-SOL"]}, {"type":"trade","codes":["KRW-BTC", "KRW-SOL"]}, {"type":"orderbook","codes":["KRW-BTC", "KRW-SOL"]}, {"format": "DEFAULT"}]')
   
       def process(self, data):
           from .models import CryptoTicker, CryptoTrade, CryptoOrderbookMain, CryptoOrderbookSub
           # 在这里添加数据处理和模型操作逻辑
   

额外注意事项 #

• 确保tower应用已经添加到config/settings.py的INSTALLED_APPS中：

  INSTALLED_APPS = [
      # ...其他应用
      'tower',
  ]
  

• 使用--noreload参数时，Django不会自动重载代码，修改后需要重启服务生效。

内容的提问来源于stack exchange，提问作者Yun