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V2EX  ›  Python

Flask 中使用 PyMongo 报错 ServerSelectionTimeoutError: No servers found yet

  •  
  •   flatflax · 59 天前 · 343 次点击
    这是一个创建于 59 天前的主题,其中的信息可能已经有所发展或是发生改变。

    在写接口的时候,因为当初的弱智,没有选择 Flask-PyMongo 等库在初始化 app 的时候一并初始化 mongo 示例,而是在每个接口里创建一个 mongoClient。。

    mongo = MongoClient(mongo_uri, connect=False)

    最近新业务里,需要一个会被频繁访问,且会进行数据库查询的接口。

     ```
     # 这是逻辑函数的开始
     device_id = query_data['deviceId']
     collection = mongo.app.user
     
     user_data = collection.find_one({"deviceId": device_id})
     # 后面还有很多但是没有必要所以省略了
     ```
    

    然后发现该接口会偶尔出现下面的报错信息,但是其他会使用到 Mongo 的接口却没有出现过这个问题。报错信息如下:

     ```
     Traceback (most recent call last):
       File "/root/py27test/lib/python2.7/site-packages/flask/app.py", line 2292, in wsgi_app
         response = self.full_dispatch_request()
       File "/root/py27test/lib/python2.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
         rv = self.handle_user_exception(e)
       File "/root/py27test/lib/python2.7/site-packages/flask/app.py", line 1718, in handle_user_exception
         reraise(exc_type, exc_value, tb)
       File "/root/py27test/lib/python2.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
         rv = self.dispatch_request()
       File "/root/py27test/lib/python2.7/site-packages/flask/app.py", line 1799, in dispatch_request
         return self.view_functions[rule.endpoint](**req.view_args)
       # 这里是接口的部分
       File "./utils/v5.py", line 47, in decorated_function
         return f(*args, **kwargs)
       File "./utils/v5.py", line 1081, in user_function
         data, error_message = query_module.query(query_data, mongo)
       File "./fetcher/tools_v4.py", line 81, in user_query
         user_data = collection.find_one({"deviceId": device_id})
       # 接口的部分结束
       File "/root/py27test/lib/python2.7/site-packages/pymongo/collection.py", line 1262, in find_one
         for result in cursor.limit(-1):
       File "/root/py27test/lib/python2.7/site-packages/pymongo/cursor.py", line 1189, in next
         if len(self.__data) or self._refresh():
       File "/root/py27test/lib/python2.7/site-packages/pymongo/cursor.py", line 1087, in _refresh
         self.__session = self.__collection.database.client._ensure_session()
       File "/root/py27test/lib/python2.7/site-packages/pymongo/mongo_client.py", line 1558, in _ensure_session
         return self.__start_session(True, causal_consistency=False)
       File "/root/py27test/lib/python2.7/site-packages/pymongo/mongo_client.py", line 1511, in __start_session
         server_session = self._get_server_session()
       File "/root/py27test/lib/python2.7/site-packages/pymongo/mongo_client.py", line 1544, in _get_server_session
         return self._topology.get_server_session()
       File "/root/py27test/lib/python2.7/site-packages/pymongo/topology.py", line 427, in get_server_session
         None)
       File "/root/py27test/lib/python2.7/site-packages/pymongo/topology.py", line 199, in _select_servers_loop
         self._error_message(selector))
     ServerSelectionTimeoutError: No servers found yet
     
     ```
    

    [汗]搜索了 stackoverflow 的解决方法一个是connect=False,另一个是在 fork 前等待两秒。似乎不太适用,猛男落泪,所以来求助一哈各位大佬。

    Python:2.7.5 PyMongo:3.7.1

    1 回复  |  直到 2018-12-26 11:03:12 +08:00
        1
    careofzm   58 天前   ♥ 1
    试试连接池吧,原来遇到 redis 的时候也是这样, 用链接池好多了, 看看这个
    http://api.mongodb.com/python/current/faq.html#how-does-connection-pooling-work-in-pymongo
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