龙卷风“错误：[Errno 24]打开的文件太多”错误

魏学智

2023-03-14

问题内容：

我已经与Tornado进行了很多合作，但这是我第一次遇到这种错误。我一直在研究一个非常基本的URL缩短器。URL由另一种应用程序放入数据库中，该应用程序仅从MongoDB存储中读取URL并重定向客户端。编写基本代码后，我针对它设置了一个简单的“
Siege”测试，在运行siege（siege -c 64 -t 5m -r 1 http://example.com/MKy针对4个应用程序线程运行）约30秒钟之后，我开始获得500个响应。查看错误日志，我看到了；

ERROR:root:500 GET /MKy (127.0.0.1) 2.05ms
ERROR:root:Exception in I/O handler for fd 4
Traceback (most recent call last):
  File "/opt/python2.7/lib/python2.7/site-packages/tornado-2.1-py2.7.egg/tornado/ioloop.py", line 309, in start
  File "/opt/python2.7/lib/python2.7/site-packages/tornado-2.1-py2.7.egg/tornado/netutil.py", line 314, in accept_handler
  File "/opt/python2.7/lib/python2.7/socket.py", line 200, in accept
error: [Errno 24] Too many open files
ERROR:root:Uncaught exception GET /MKy (127.0.0.1)
HTTPRequest(protocol='http', host='shortener', method='GET', uri='/MKy', version='HTTP/1.0', remote_ip='127.0.0.1', body='', headers={'Host': 'shortener', 'Accept-Encoding': 'gzip', 'X-Real-Ip': '94.23.155.32', 'X-Forwarded-For': '94.23.155.32', 'Connection': 'close', 'Accept': '*/*', 'User-Agent': 'JoeDog/1.00 [en] (X11; I; Siege 2.66)'})
Traceback (most recent call last):
  File "/opt/python2.7/lib/python2.7/site-packages/tornado-2.1-py2.7.egg/tornado/web.py", line 1040, in wrapper
  File "main.py", line 58, in get
  File "main.py", line 21, in dbmongo
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 349, in __init__
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 510, in __find_master
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 516, in __try_node
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/database.py", line 301, in command
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/collection.py", line 441, in find_one
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/cursor.py", line 539, in loop
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/cursor.py", line 560, in _refresh
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/cursor.py", line 620, in __send_message
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 735, in _send_message_with_response
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 591, in __stream
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 200, in get_stream
  File "/opt/python2.7/lib/python2.7/site-packages/apymongo-0.0.1-py2.7-linux-x86_64.egg/apymongo/connection.py", line 559, in __connect
AutoReconnect: could not connect to [('127.0.0.1', 27017)]

重要（我想）；

错误：[Errno 24]打开的文件太多

编码; （很简单）

import tornado.ioloop
import tornado.web
import tornado.escape
import apymongo
import time
import sys

#Useful stuff (Connect to Mongo)
class setup(tornado.web.RequestHandler):
    def dbmongo(self):
        if not hasattr(self, '_dbmongo'):
            self._dbmongo = apymongo.Connection("127.0.0.1", 27017)
        return self._dbmongo


#Basic method to lookup URLs from Mongo and redirect accordingly
class expand(setup):
    @tornado.web.asynchronous
    def get(self, url):
        self.mongo = self.dbmongo()

        #Lookup the URL
        cursor = self.mongo.rmgshortlinks.links.find_one({'short':url}, self.direct)

    def direct(self, response):
        if response == None:
            self.send_error(404)
            self.finish()
            return

        link = tornado.escape.url_unescape(response['long'])

        #Bounce the client
        self.write("<!DOCTYPE html><html><head><meta charset=\"UTF-8\" /><meta http-equiv=\"refresh\" content=\"0;URL="+link+"\"</head><body><a href=\""+link+"\">Click Here</a></body></html>")
        self.finish();


#Define the URL routes
application = tornado.web.Application([
    (r"/([a-zA-Z0-9]+)", expand)
])

#Start the server
if __name__ == "__main__":
    listening_port = int(sys.argv[1])

    if listening_port > 0:
        application.listen(listening_port)
        tornado.ioloop.IOLoop.instance().start()
    else:
        sys.stderr.write("No port specified!")

我正在使用的开发服务器具有8个内核和64GB内存，运行RedHat Enterprise Linux 5和Python
2.6。之前，我从未遇到过Tornado / Async Mongo应用程序这类问题。

可能有用的信息；

[root@puma ~]# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 31374
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 31374
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

（打开的文件仅设置为1024，但我认为这已经足够了）

Tornado /
Apymongo是否无法正确关闭连接？应用程序位于NGINX后面，但使用HTTP连接，Apymongo应该通过TCP连接，但可能使用套接字。即使这样它也应该共享/共享连接吗？

按照建议，将应用程序移动到我们的其中一台测试服务器上，最大打开文件数限制为61440，在围攻中运行约30秒后出现相同错误。

问题答案：

很简单，为每个请求实例化RequestHandler对象。这意味着您要保存的缓存对象位于RequestHandler（例如，expand）对象上。

如果要向dbmongo（…）函数添加一个简单的“ print’CREATED！’”，您会看到它是在每个GET请求中创建的。

您需要做的是将处理程序附加到类对象，或者根据需要附加“全局”，尽管最好的情况是将其放在Tornado Application对象上。

简单：

class setup(tornado.web.RequestHandler):
    @classmethod
    def dbmongo(cls):
        if not hasattr(cls, '_dbmongo'):
            cls._dbmongo = apymongo.Connection("127.0.0.1", 27017)
        return cls._dbmongo

第二种方法是使其在文件中成为全局文件：

dbmongo_connection = None
def dbmongo():
    if not dbmongo_connection:
        dbmongo_connection = apymongo.Connection("127.0.0.1", 27017)
    return dbmongo_connection

两者都有相同的问题，即如果您有很多想要使用数据库连接的类，则很难共享它。由于数据库是一个共享实体，因此您可能希望为整个应用程序使用一个实体。

class MongoMixin(object):
    def mongodb(self):
        if not hasattr(self.application, 'mongodb'):
            self.application.mongodb = apymongo.Connection(self.application.settings.get("mongohost", "127.0.0.1"), 27017)
        return self.application.mongodb

class expand(tornado.web.RequestHandler, MongoMixin):
    def get(self):
       db = self.mongodb()

龙卷风“错误：[Errno 24]打开的文件太多”错误

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