uwsgi setup on every 4 minutes reload (it's important)
Connect to MongoDB via register_connection:
mongo_db =

Sometime after reload read operation give error:
Traceback (most recent call last):
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1997, in _call_
return self.wsgi_app(environ, start_response)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/werkzeug/contrib/fixers.py", line 152, in _call_
return self.app(environ, start_response)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1985, in wsgi_app
response = self.handle_exception(e)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask_cors/extension.py", line 161, in wrapped_function
return cors_after_request(app.make_response(f(*args, **kwargs)))
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1540, in handle_exception
reraise(exc_type, exc_value, tb)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1982, in wsgi_app
response = self.full_dispatch_request()
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1614, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask_cors/extension.py", line 161, in wrapped_function
return cors_after_request(app.make_response(f(*args, **kwargs)))
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1517, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1612, in full_dispatch_request
rv = self.dispatch_request()
File "/home/sudoaccess/backend/lib/python2.7/site-packages/flask/app.py", line 1598, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "./tools/utils.py", line 158, in view_func
return f(*args, **kwargs)
File "./bproute/tools.py", line 369, in get_main_statistics
tenders_num_total = TenderRequest.objects(Q(is_confirmed=True)).count() or 1
File "/home/sudoaccess/backend/lib/python2.7/site-packages/mongoengine/queryset/manager.py", line 37, in _get_
queryset = queryset_class(owner, owner._get_collection())
File "/home/sudoaccess/backend/lib/python2.7/site-packages/mongoengine/document.py", line 206, in _get_collection
cls.ensure_indexes()
File "/home/sudoaccess/backend/lib/python2.7/site-packages/mongoengine/document.py", line 836, in ensure_indexes
collection.create_index(fields, background=background, **opts)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/collection.py", line 1529, in create_index
self.__create_index(keys, kwargs)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/collection.py", line 1417, in __create_index
with self._socket_for_writes() as sock_info:
File "/usr/lib/python2.7/contextlib.py", line 17, in _enter_
return self.gen.next()
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/mongo_client.py", line 823, in _get_socket
server = self._get_topology().select_server(selector)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/topology.py", line 214, in select_server
address))
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/topology.py", line 202, in select_servers
selector, address)
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/topology_description.py", line 211, in apply_selector
selector(Selection.from_topology_description(self)))
File "/home/sudoaccess/backend/lib/python2.7/site-packages/pymongo/topology_description.py", line 188, in apply_local_threshold
if (s.round_trip_time - fastest) <= threshold]
TypeError: unsupported operand type(s) for -: 'NoneType' and 'NoneType'
[pid: 5747|app: 0|req: 1/6] 52.169.30.199 ()

[Wed Apr 26 22:12:12 2017] GET /api/v1/tools/main_statistics => generated 0 bytes in 0 msecs (HTTP/1.1 500) 0 headers in 0 bytes (0 switches on core 0)