django中的猴子修补请求
django中的猴子修补请求
提问于 2016-01-03 22:38:38
我正在尝试创建django视图，发出几个异步http请求并返回合并的数据。
下面是一个在单独文件中工作的示例：
import gevent
from gevent import monkey
monkey.patch_all()
import requests
results = {}
processes = []
def fill_results(url, position):
print(url, position, 'starting')
results[position] = {'url': url, 'response': requests.get(url)}
print(url, position, 'ready')
urls = ['http://www.accessgenealogy.com'] * 5
for position, url in enumerate(urls):
processes.append(gevent.spawn(fill_results, url, position))
gevent.joinall(processes)
print(results)我得到的输出是：
('http://www.accessgenealogy.com', 0, 'starting')
('http://www.accessgenealogy.com', 1, 'starting')
('http://www.accessgenealogy.com', 2, 'starting')
('http://www.accessgenealogy.com', 3, 'starting')
('http://www.accessgenealogy.com', 4, 'starting')
('http://www.accessgenealogy.com', 3, 'ready')
('http://www.accessgenealogy.com', 0, 'ready')
('http://www.accessgenealogy.com', 4, 'ready')
('http://www.accessgenealogy.com', 2, 'ready')
('http://www.accessgenealogy.com', 1, 'ready')
{0: {'url': 'http://www.accessgenealogy.com', 'response': <Response [200]>}, 1: {'url': 'http://www.accessgenealogy.com', 'response': <Response [200]>}, 2: {'url': 'http://www.accessgenealogy.com', 'response': <Response [200]>}, 3: {'url': 'http://www.accessgenealogy.com', 'response': <Response [200]>}, 4: {'url': 'http://www.accessgenealogy.com', 'response': <Response [200]>}}因此，这些请求确实是不同步的。
当我将相同的代码粘贴到django 1.9视图中时，monkey.patch_all()会破坏django：
Traceback (most recent call last):
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/gevent/greenlet.py", line 327, in run
result = self._run(*self.args, **self.kwargs)
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/utils/autoreload.py", line 226, in wrapper
fn(*args, **kwargs)
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run
self.check_migrations()
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 163, in check_migrations
executor = MigrationExecutor(connections[DEFAULT_DB_ALIAS])
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/migrations/executor.py", line 20, in __init__
self.loader = MigrationLoader(self.connection)
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/migrations/loader.py", line 49, in __init__
self.build_graph()
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/migrations/loader.py", line 176, in build_graph
self.applied_migrations = recorder.applied_migrations()
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/migrations/recorder.py", line 65, in applied_migrations
self.ensure_schema()
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/migrations/recorder.py", line 52, in ensure_schema
if self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor()):
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/backends/base/base.py", line 229, in cursor
self.validate_thread_sharing()
File "/Users/1111/.virtualenvs/django_cpa/lib/python2.7/site-packages/django/db/backends/base/base.py", line 523, in validate_thread_sharing
% (self.alias, self._thread_ident, thread.get_ident()))
DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 140735166436112 and this is thread id 4488713392.
<Greenlet at 0x10b8c54b0: wrapper(use_static_handler=True, settings=None, pythonpath=None, verbosity=1, traceback=False, addrport='8000', no_color=False, use_ipv6=False, use_threading=True, use_reloader=True, insecure_serving=False)> failed with DatabaseError在不破坏django的情况下，我应该具体地修补什么来使这个工作正常？
回答 1
Stack Overflow用户
发布于 2016-01-04 19:10:07
你可以尝试几件事：
- 确保您没有在greenlets中执行任何数据库操作。
- 在视图中导入gevent和修补程序，然后在完成后打开修补程序。
下面是一个例子：
class MyView(View):
def get(self, request, *args, **kwargs):
def fill_results(url, position):
# Point 1: no DB operations inside here!
results[position] = {'url': url, 'response': request.get(url)}
urls = ['http://www.accessgenealogy.com'] * 5
# import gevent and patch
import gevent
from gevent import monkey
monkey.patch_all()
processes = []
for position, url in enumerate(urls):
processes.append(gevent.spawn(fill_results, url, position))
gevent.joinall(processes)
# Point 2: unpatch after use
reload(socket)
return HttpResponse()页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/34582454
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