Gunicorn+flask+pymongo+gevent初始化时挂起

Question

这是一个简单的测试应用：

from gevent import monkey
monkey.patch_all()

from pymongo import Connection, MongoClient
from flask import Flask, make_response

app = Flask(__name__)
print "connect"
connection = MongoClient("host1, host2, host3", 27017, max_pool_size=4, **{"connectTimeoutMS": 3000, "socketTimeoutMS": 3000, "use_greenlets": True})
print "db"
db = connection.barn_2

@app.route('/')
def hello_world():
    return make_response("Hello world!", 200, {'Content-type': 'application/json; charset=UTF-8'})

if __name__ == '__main__':
    app.run()

如果单独运行这个应用，它工作得非常好：

shcheklein@hostname:~$ python test.py
connect
db
 * Running on http://127.0.0.1:5000/
127.0.0.1 - - [07/Apr/2014 13:07:31] "GET / HTTP/1.1" 200 -
^CKeyboardInterrupt

但是用gunicorn启动时就无法正常启动：

shcheklein@hostname:~$ gunicorn -w 1 -k gevent -t 5 --debug test:app
2014-04-07 13:15:04 [9752] [INFO] Starting gunicorn 18.0
2014-04-07 13:15:04 [9752] [INFO] Listening at: http://127.0.0.1:8000 (9752)
2014-04-07 13:15:04 [9752] [INFO] Using worker: gevent
2014-04-07 13:15:04 [9757] [INFO] Booting worker with pid: 9757
connect
2014-04-07 13:15:09 [9752] [CRITICAL] WORKER TIMEOUT (pid:9757)
2014-04-07 13:15:09 [9752] [CRITICAL] WORKER TIMEOUT (pid:9757)
2014-04-07 13:15:10 [9787] [INFO] Booting worker with pid: 9787
connect
2014-04-07 13:15:15 [9752] [CRITICAL] WORKER TIMEOUT (pid:9787)
2014-04-07 13:15:15 [9752] [CRITICAL] WORKER TIMEOUT (pid:9787)
2014-04-07 13:15:16 [9809] [INFO] Booting worker with pid: 9809
connect
2014-04-07 13:15:21 [9752] [CRITICAL] WORKER TIMEOUT (pid:9809)
2014-04-07 13:15:21 [9752] [CRITICAL] WORKER TIMEOUT (pid:9809)
2014-04-07 13:15:22 [9830] [INFO] Booting worker with pid: 9830

一些说明：

• 如果关闭gevent（猴子补丁和gunicorn工作类），它就能正常工作
• 如果每次请求都创建一个新的数据库对象，它也能正常工作
• 版本信息：gevent 1.0，gunicorn 18.0，pymongo 2.6.2，flask 0.9，python 2.6.5

我怀疑这样初始化和共享数据库连接池的方法是否合适。不过，我找不到其他方法来在请求之间共享一个对象。

Answer 1

也许这个 Gunicorn 的 问题 能给你一些额外的信息和帮助。

Answer 2

好的，这个问题和以下内容是一样的：

https://jira.mongodb.org/browse/PYTHON-607

对我有效的解决方法有：

from gevent import monkey
monkey.patch_all()

unicode('foo').encode('idna')

...

或者：

shcheklein@hostname:~$ export GEVENT_RESOLVER=ares
shcheklein@hostname:~$ gunicorn -w 1 -k gevent -t 5 --debug test:app