def populate_apps(self, installed_apps=None):
"""
Populate app-related information.
This method imports each application module.
It is thread safe and idempotent, but not reentrant.
"""
if self._apps_loaded:
return
# Since populate_apps() may be a side effect of imports, and since
# it will itself import modules, an ABBA deadlock between threads
# would be possible if we didn't take the import lock. See #18251.
with import_lock():
if self._apps_loaded:
return
# app_config should be pristine, otherwise the code below won't
# guarantee that the order matches the order in INSTALLED_APPS.
if self.app_configs:
raise RuntimeError("populate_apps() isn't reentrant")
# Application modules aren't expected to import anything, and
# especially not other application modules, even indirectly.
# Therefore we simply import them sequentially.
if installed_apps is None:
installed_apps = settings.INSTALLED_APPS
for app_name in installed_apps:
app_config = AppConfig.create(app_name)
self.app_configs[app_config.label] = app_config
self.get_models.cache_clear()
self._apps_loaded = True
def populate(self, installed_apps=None):
"""
Loads application configurations and models.
This method imports each application module and then each model module.
It is thread safe and idempotent, but not reentrant.
"""
if self.ready:
return
# Since populate() may be a side effect of imports, and since it will
# itself import modules, an ABBA deadlock between threads would be
# possible if we didn't take the import lock. See #18251.
with import_lock():
if self.ready:
return
# app_config should be pristine, otherwise the code below won't
# guarantee that the order matches the order in INSTALLED_APPS.
if self.app_configs:
raise RuntimeError("populate() isn't reentrant")
# Load app configs and app modules.
for entry in installed_apps:
if isinstance(entry, AppConfig):
app_config = entry
else:
app_config = AppConfig.create(entry)
if app_config.label in self.app_configs:
raise ImproperlyConfigured(
"Application labels aren't unique, "
"duplicates: %s" % app_config.label)
self.app_configs[app_config.label] = app_config
# Check for duplicate app names.
counts = Counter(app_config.name
for app_config in self.app_configs.values())
duplicates = [
name for name, count in counts.most_common() if count > 1
]
if duplicates:
raise ImproperlyConfigured("Application names aren't unique, "
"duplicates: %s" %
", ".join(duplicates))
# Load models.
for app_config in self.app_configs.values():
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
self.clear_cache()
self.ready = True
for app_config in self.get_app_configs():
app_config.ready()
def populate(self, installed_apps=None):
"""
Loads application configurations and models.
This method imports each application module and then each model module.
It is thread safe and idempotent, but not reentrant.
"""
if self.ready:
return
# Since populate() may be a side effect of imports, and since it will
# itself import modules, an ABBA deadlock between threads would be
# possible if we didn't take the import lock. See #18251.
with import_lock():
if self.ready:
return
# app_config should be pristine, otherwise the code below won't
# guarantee that the order matches the order in INSTALLED_APPS.
if self.app_configs:
raise RuntimeError("populate() isn't reentrant")
# Load app configs and app modules.
for entry in installed_apps:
if isinstance(entry, AppConfig):
app_config = entry
else:
app_config = AppConfig.create(entry)
if app_config.label in self.app_configs:
raise ImproperlyConfigured(
"Application labels aren't unique, "
"duplicates: %s" % app_config.label)
self.app_configs[app_config.label] = app_config
# Check for duplicate app names.
counts = Counter(
app_config.name for app_config in self.app_configs.values())
duplicates = [
name for name, count in counts.most_common() if count > 1]
if duplicates:
raise ImproperlyConfigured(
"Application names aren't unique, "
"duplicates: %s" % ", ".join(duplicates))
# Load models.
for app_config in self.app_configs.values():
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
self.clear_cache()
self.ready = True
for app_config in self.get_app_configs():
app_config.ready()
def populate_models(self):
"""
Populate model-related information.
This method imports each models module.
It is thread safe, idempotent and reentrant.
"""
if self._models_loaded:
return
# Since populate_models() may be a side effect of imports, and since
# it will itself import modules, an ABBA deadlock between threads
# would be possible if we didn't take the import lock. See #18251.
with import_lock():
if self._models_loaded:
return
self.populate_apps()
# Models modules are likely to import other models modules, for
# example to reference related objects. As a consequence:
# - we deal with import loops by postponing affected modules.
# - we provide reentrancy by making import_models() idempotent.
outermost = not hasattr(self, '_postponed')
if outermost:
self._postponed = []
for app_config in self.app_configs.values():
if app_config.models is not None:
continue
try:
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
except ImportError:
self._postponed.append(app_config)
if outermost:
for app_config in self._postponed:
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
del self._postponed
self.get_models.cache_clear()
self._models_loaded = True
def populate(self, installed_apps=None):
"""
Loads application configurations and models.
This method imports each application module and then each model module.
It is thread safe and idempotent, but not reentrant.
"""
if self.ready:
return
# Since populate() may be a side effect of imports, and since it will
# itself import modules, an ABBA deadlock between threads would be
# possible if we didn't take the import lock. See #18251.
with import_lock():
if self.ready:
return
# app_config should be pristine, otherwise the code below won't
# guarantee that the order matches the order in INSTALLED_APPS.
if self.app_configs:
raise RuntimeError("populate() isn't reentrant")
# Load app configs and app modules.
for entry in installed_apps:
if isinstance(entry, AppConfig):
app_config = entry
else:
app_config = AppConfig.create(entry)
self.app_configs[app_config.label] = app_config
# Load models.
for app_config in self.app_configs.values():
all_models = self.all_models[app_config.label]
app_config.import_models(all_models)
self.clear_cache()
self.ready = True
for app_config in self.get_app_configs():
app_config.setup()
