1     def populate(self, installed_apps=None):
 2         """
 3         Loads application configurations and models.
 4 
 5         This method imports each application module and then each model module.
 6 
 7         It is thread safe and idempotent, but not reentrant.
 8         """
 9         if
 
 self.ready:
10             return
11 
12         # populate() might be called by two threads in parallel on servers
13         # that create threads before initializing the WSGI callable.
14         with self._lock:
15             if self.ready:
16                 return
17 
18             # app_config should be pristine, otherwise the code below won't
 

19             # guarantee that the order matches the order in INSTALLED_APPS.
20             if self.app_configs:
21                 raise RuntimeError("populate() isn't reentrant")
22 
23             # Phase 1: initialize app configs and import app modules.
24             for entry in installed_apps:
 
25                 if isinstance(entry, AppConfig):
26                     app_config = entry
27                 else:
28                     app_config = AppConfig.create(entry)
29                 if app_config.label in self.app_configs:
30                     raise ImproperlyConfigured(
31                         "Application labels aren't unique, "
32                         "duplicates: %s" % app_config.label)
33 
34                 self.app_configs[app_config.label] = app_config
35                 app_config.apps = self
36 
37             # Check for duplicate app names.
38             counts = Counter(
39                 app_config.name for app_config in self.app_configs.values())
40             duplicates = [
41                 name for name, count in counts.most_common() if count > 1]
42             if duplicates:
43                 raise ImproperlyConfigured(
44                     "Application names aren't unique, "
45                     "duplicates: %s" % ", ".join(duplicates))
46 
47             self.apps_ready = True
48 
49             # Phase 2: import models modules.
50             for app_config in self.app_configs.values():
51                 app_config.import_models()
52 
53             self.clear_cache()
54 
55             self.models_ready = True
56 
57             # Phase 3: run ready() methods of app configs.
58             for app_config in self.get_app_configs(): #原始碼無try
59                 try:
60                     app_config.ready()
61                 except:
62                     pass
63 
64             self.ready = True

celery任務啟動時，admin註冊出錯，需做修改。