使用 Django 通道从 python 3.6 升级到 python 3.7 时出现 SynchronousOnlyOperation 错误
SynchronousOnlyOperation error when upgrading from python 3.6 to python 3.7 using django channels
我一直在尝试将我们的 Django 和 Django 频道应用程序 python 从 3.6 升级到 3.7。有了这个更改，Django 会在任何 HTTP 请求发出时抛出 SynchronousOnlyOperation（即使它与 WebSockets 无关）。我的猜测是 python 升级以某种方式使 Django 检查更加严格。
我相信 Django 通道同时服务于 HTTP 请求和 WebSocket 请求，因此它希望所有代码都符合异步要求。
如何让 Django 通道 runserver 同步到 运行 wsgi 应用程序，同时通道消费者异步？
# project/asgi.py
application = ProtocolTypeRouter({"http": get_asgi_application(), "websocket": routing})
# project/wsgi.py
application = get_wsgi_application()
堆栈跟踪：
我很清楚 运行 用于普通 wsgi 视图的 auth 中间件不符合异步，我怎样才能在同步环境中将其设置为 运行？
ERROR Internal Server Error: /a/api
Traceback (most recent call last):
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 233, in _get_session
return self._session_cache
AttributeError: 'SessionStore' object has no attribute '_session_cache'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/___/___/___/___/apps/core/middleware.py", line 60, in __call__
request.is_user_verified = request.user.is_verified()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 240, in inner
self._setup()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 376, in _setup
self._wrapped = self._setupfunc()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django_otp/middleware.py", line 38, in _verify_user
user.otp_device = None
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 270, in __setattr__
self._setup()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 376, in _setup
self._wrapped = self._setupfunc()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/middleware.py", line 24, in <lambda>
request.user = SimpleLazyObject(lambda: get_user(request))
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/middleware.py", line 12, in get_user
request._cached_user = auth.get_user(request)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/__init__.py", line 174, in get_user
user_id = _get_user_session_key(request)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/__init__.py", line 58, in _get_user_session_key
return get_user_model()._meta.pk.to_python(request.session[SESSION_KEY])
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 65, in __getitem__
return self._session[key]
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 238, in _get_session
self._session_cache = self.load()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/db.py", line 43, in load
s = self._get_session_from_db()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/db.py", line 34, in _get_session_from_db
expire_date__gt=timezone.now()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 425, in get
num = len(clone)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 269, in __len__
self._fetch_all()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 1303, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 53, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1154, in execute_sql
cursor = self.connection.cursor()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/asyncio.py", line 24, in inner
raise SynchronousOnlyOperation(message)
django.core.exceptions.SynchronousOnlyOperation: You cannot call this from an async context - use a thread or sync_to_async.
版本
Django==3.1.1
channels==3.0.2
channels-redis==3.2.0
总结一下我的尝试：
- 首先，我有一个频道应用程序，它根本没有数据库，除了静态文件之外没有贡献应用程序。
- 我添加了数据库、DRF 和一个具有单一模型和 list/detail 视图的应用程序
- 启用同步 http 消费者：
# dwtools.routing
from channels.routing import ProtocolTypeRouter, URLRouter
from django.core.asgi import get_asgi_application
import romanize.routing
application = ProtocolTypeRouter(
{
"websocket": URLRouter(romanize.routing.websocket_urlpatterns),
"http": get_asgi_application(),
},
)
- 设置：
INSTALLED_APPS = [
"channels",
"romanize.apps.RomanizeConfig",
"django.contrib.staticfiles",
"rest_framework",
"agencies.apps.AgenciesConfig",
]
WSGI_APPLICATION = "dwtools.wsgi.application"
ASGI_APPLICATION = "dwtools.routing.application"
我可以调出 DRF 的标准视图、创建条目等
然后添加了一个访问数据库的简单中间件（获取代理数量并将其放入请求中）。连 MiddlewareMixin 都不用，准系统 init 就可以调用 protocol.
System check identified no issues (0 silenced).
December 07, 2020 - 14:38:56
Django version 3.1.4, using settings 'dwtools.settings'
Starting ASGI/Channels version 3.0.2 development server at http://127.0.0.1:3401/
# ^^^^^^^^ ^^^^^^^^^^^ ( Channels runserver)
Quit the server with CONTROL-C.
HTTP GET /agencies/ 200 [0.05, 127.0.0.1:60460]
堆栈使用本地 nginx 为 /ws (websocket) 和 /agencies (http) 路由到端口 3401。也许你发现了什么...
终于搞清楚了。对于我们来说，我们使用 gevent 并且在我们的 manage.py
中有这一行
# manage.py
import gevent
gevent.patch_all()
无论出于何种原因，这在 python 3.7+、Django 频道和 Django 中都不能很好地发挥作用（其中 python 3.6、Django 频道和 Django 工作正常）。
我们很幸运，能够从我们的代码库中删除它；我们没有弄清楚如何修复 gevent 补丁。
我一直在尝试将我们的 Django 和 Django 频道应用程序 python 从 3.6 升级到 3.7。有了这个更改，Django 会在任何 HTTP 请求发出时抛出 SynchronousOnlyOperation（即使它与 WebSockets 无关）。我的猜测是 python 升级以某种方式使 Django 检查更加严格。
我相信 Django 通道同时服务于 HTTP 请求和 WebSocket 请求，因此它希望所有代码都符合异步要求。
如何让 Django 通道 runserver 同步到 运行 wsgi 应用程序，同时通道消费者异步？
# project/asgi.py
application = ProtocolTypeRouter({"http": get_asgi_application(), "websocket": routing})
# project/wsgi.py
application = get_wsgi_application()
堆栈跟踪： 我很清楚 运行 用于普通 wsgi 视图的 auth 中间件不符合异步，我怎样才能在同步环境中将其设置为 运行？
ERROR Internal Server Error: /a/api
Traceback (most recent call last):
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 233, in _get_session
return self._session_cache
AttributeError: 'SessionStore' object has no attribute '_session_cache'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/___/___/___/___/apps/core/middleware.py", line 60, in __call__
request.is_user_verified = request.user.is_verified()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 240, in inner
self._setup()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 376, in _setup
self._wrapped = self._setupfunc()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django_otp/middleware.py", line 38, in _verify_user
user.otp_device = None
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 270, in __setattr__
self._setup()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/functional.py", line 376, in _setup
self._wrapped = self._setupfunc()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/middleware.py", line 24, in <lambda>
request.user = SimpleLazyObject(lambda: get_user(request))
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/middleware.py", line 12, in get_user
request._cached_user = auth.get_user(request)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/__init__.py", line 174, in get_user
user_id = _get_user_session_key(request)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/auth/__init__.py", line 58, in _get_user_session_key
return get_user_model()._meta.pk.to_python(request.session[SESSION_KEY])
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 65, in __getitem__
return self._session[key]
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/base.py", line 238, in _get_session
self._session_cache = self.load()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/db.py", line 43, in load
s = self._get_session_from_db()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/contrib/sessions/backends/db.py", line 34, in _get_session_from_db
expire_date__gt=timezone.now()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 425, in get
num = len(clone)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 269, in __len__
self._fetch_all()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 1303, in _fetch_all
self._result_cache = list(self._iterable_class(self))
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/query.py", line 53, in __iter__
results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1154, in execute_sql
cursor = self.connection.cursor()
File "/___/___/.pyenv/versions/pd37/lib/python3.7/site-packages/django/utils/asyncio.py", line 24, in inner
raise SynchronousOnlyOperation(message)
django.core.exceptions.SynchronousOnlyOperation: You cannot call this from an async context - use a thread or sync_to_async.
版本
Django==3.1.1
channels==3.0.2
channels-redis==3.2.0
总结一下我的尝试：
- 首先，我有一个频道应用程序，它根本没有数据库，除了静态文件之外没有贡献应用程序。
- 我添加了数据库、DRF 和一个具有单一模型和 list/detail 视图的应用程序
- 启用同步 http 消费者：
# dwtools.routing
from channels.routing import ProtocolTypeRouter, URLRouter
from django.core.asgi import get_asgi_application
import romanize.routing
application = ProtocolTypeRouter(
{
"websocket": URLRouter(romanize.routing.websocket_urlpatterns),
"http": get_asgi_application(),
},
)
- 设置：
INSTALLED_APPS = [
"channels",
"romanize.apps.RomanizeConfig",
"django.contrib.staticfiles",
"rest_framework",
"agencies.apps.AgenciesConfig",
]
WSGI_APPLICATION = "dwtools.wsgi.application"
ASGI_APPLICATION = "dwtools.routing.application"
我可以调出 DRF 的标准视图、创建条目等
然后添加了一个访问数据库的简单中间件（获取代理数量并将其放入请求中）。连 MiddlewareMixin 都不用，准系统 init 就可以调用 protocol.
System check identified no issues (0 silenced).
December 07, 2020 - 14:38:56
Django version 3.1.4, using settings 'dwtools.settings'
Starting ASGI/Channels version 3.0.2 development server at http://127.0.0.1:3401/
# ^^^^^^^^ ^^^^^^^^^^^ ( Channels runserver)
Quit the server with CONTROL-C.
HTTP GET /agencies/ 200 [0.05, 127.0.0.1:60460]
堆栈使用本地 nginx 为 /ws (websocket) 和 /agencies (http) 路由到端口 3401。也许你发现了什么...
终于搞清楚了。对于我们来说，我们使用 gevent 并且在我们的 manage.py
# manage.py
import gevent
gevent.patch_all()
无论出于何种原因，这在 python 3.7+、Django 频道和 Django 中都不能很好地发挥作用（其中 python 3.6、Django 频道和 Django 工作正常）。
我们很幸运，能够从我们的代码库中删除它；我们没有弄清楚如何修复 gevent 补丁。