Question

我正在尝试使用Redis lpush/blpop同步传入连接。

例如，一个用户尝试加载页面，他的连接通过blpop阻止。只要第二个用户开始加载页面lpush，就会释放第一个连接。

相反，第一个blpop似乎阻止整个服务器，第二个连接永远不会进入视图。

这是我正在尝试的最小例子：

views.py：

from django.http import HttpResponse
import redis

r = redis.StrictRedis()

def two_view(request):
    print('Starting request')
    if r.get('waiting') == '1':
        print('Someone is waiting')
        r.set('waiting', 0)
        print('Pushing key')
        r.lpush('waiting_key', 1)
        return HttpResponse('Released lock, we both go')
    else:
        print('Nobody is waiting.')
        r.set('waiting', 1)
        print('Begin waiting for other')
        r.blpop('waiting_key')
        return HttpResponse('set waiting higher, to: {}'.format(r.get('waiting')))

manage.py：

#!/usr/bin/env python
from gevent import monkey
monkey.patch_all()
import os
import sys

if __name__ == "__main__":
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "basic.settings")

    from django.core.management import execute_from_command_line

    execute_from_command_line(sys.argv)

urls.py：

from django.conf.urls import patterns, include, url
from django.contrib import admin
from views import two_view

admin.autodiscover()

urlpatterns = patterns('',
    url(r'^admin/', include(admin.site.urls)),
    url(r'^$', two_view),
)

当我指向两个标签时的输出：

(env)Vincents-MacBook-Pro:basic vkhougaz$ python manage.py runserver
Validating models...

0 errors found
April 04, 2014 - 02:38:34
Django version 1.6.2, using settings 'basic.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
Starting request
Nobody is waiting.
Begin waiting for other

两个标签都没有完成加载。

以下是我正在尝试做的一个工作示例：

import redis
from gevent import monkey
import gevent
monkey.patch_all(thread=False)
from time import sleep

conpol = redis.ConnectionPool()

def do_lock_thing_1():
    r = redis.StrictRedis(connection_pool=conpol)
    print('starting thing 1')
    r.blpop('k')
    print('finishing thing 1')

def do_lock_thing_2():
    r = redis.StrictRedis(connection_pool=conpol)

    print('starting thing 2')
    sleep(1)
    r.lpush('k', 1)
    print('finishing thing 2')

r2 = redis.StrictRedis(connection_pool=conpol)

r2.delete('k')

t1 = gevent.spawn(do_lock_thing_1)
t2 = gevent.spawn(do_lock_thing_2)

gevent.joinall([t1, t2])

输出：

starting thing 1
starting thing 2
<1 second delay>
finishing thing 2
finishing thing 1

我错过了什么？

Answer 1

事实证明问题不在于django或gevent或redis，而是chrome正在排队连接。如果我使用两种不同的浏览器，代码将按预期工作。

Blocking calls with Gevent and WSGI

使用Redis在Django中同步请求

1 个答案: