[PYTHON] I get an error when trying meinheld + WebSocket + mongodb

To the meinheld professor who is indebted to me on a daily basis There is a WebSocketMiddleware that makes it easy to implement WebSockets for existing wsgi apps. If it's a code written by a hetareyaro like me, it's very slow and unusable unless it's taken care of by meinheld, so I can't get up.

So, when I thought about making a recent cool-looking app that uses such WebSocket, Of course, mongodb will be chosen as a DB option with such momentum. yep.

So, mongodb while referring to Sample of applying meinheld WebSocketMiddleware to flask etc. written by the author of meinheld himself. I wonder if it will be like this when I try to build

main.py

from shimehari import Shimehari
from mongoengine import connect
from meinheld import server, middleware
import config


def connectDB():
    connect(config['DB_NAME'])

app = Shimehari(__name__)

if __name__ == '__main__':
    connectDB()
    server.listen(("0.0.0.0", 3000))
    server.run(middleware.WebSocketMiddleware(app))

Try to start

$ (venv) bin/python main.py

People People People People People People

Sudden error < ￣Y^Y^Y^Y^Y^Y^Y￣

Trace back

Traceback (most recent call last):
  File "main.py", line 25, in <module>
    connectDB()
  File "/project/path/main.py", line 13, in connectDB
    connect(config['DB_NAME'])
  File "/project/path/lib/python2.7/site-packages/mongoengine/connection.py", line 162, in connect
    return get_connection(alias)
  File "/project/path/lib/python2.7/site-packages/mongoengine/connection.py", line 126, in get_connection
    raise ConnectionError("Cannot connect to database %s :\n%s" % (alias, e))
mongoengine.connection.ConnectionError: Cannot connect to database default :
call from same greenlet

I don't know what you're talking about. I wondered if the host around the port was strange Suddenly I changed the implementation as follows and it worked.

main.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from shimehari import Shimehari


def connectDB():
    connect(config['DB_NAME'])

app = Shimehari(__name__)

if __name__ == '__main__':
    connectDB()
    #import after connecting to db
    from meinheld import server, middleware
    server.listen(("0.0.0.0", 3000))
    server.run(middleware.WebSocketMiddleware(app))

It's a natural thing for the mohawk people who are messing around with it! It may be something like that I didn't come out at all when I googled I think that there are more people who use node.js when doing WebSocket, so I think that's the case, while thinking For the time being, it worked with this, so I'm glad Is it better to replace connecetDB with something like with?