I have a Flask python web app on uWSGI/nginx that works fine, except when I use pymongo, specifically when I initialize the MongoClient class. I get the following nginx error when I try to access the app while using pymongo:
019/02/19 21:58:13 [error] 16699#0: *5 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 127.0.0.1, server: example.com, request: "GET /api/test HTTP/1.1", upstream: "uwsgi://unix:/var/www/html/myapp/myapp.sock:”, host: “example.com”
My small test app:
from flask import Flask from flask_cors import CORS from bson.json_util import dumps import pymongo DEBUG = True app = Flask(__name__) app.config.from_object(__name__) CORS(app) client = pymongo.MongoClient() # This line db = client.myapp @app.route('/api/test') def test(): item = db.items.find_one() return item['name'] def create_app(app_name='MYAPP'): return app # if __name__ == '__main__': # app.run(debug=True, threaded=True, host='0.0.0.0') If I run this app from the command line (python app.py) it works fine accessing 0.0.0.0:5000/api/test, so I'm pretty sure it's just a uWSGI configuration issue. My first thought was to increase the uwsgi_read_timeout parameter in my nginx config file:
uwsgi_read_timeout 3600
server { listen 80 default_server; listen [::]:80 default_server; server_name example.com www.example.com; location /api { include uwsgi_params; uwsgi_read_timeout 3600; uwsgi_pass unix:/var/www/html/myapp/myapp.sock; } location / { root /var/www/html/myapp; try_files $uri $uri/ /index.html; } #return 301 https://$server_name$request_uri; } But it had no apparent effect. My uWSGI app is running as a service, using the following config (myapp.ini):
[uwsgi] module = wsgi:app master = true processes = 4 enable-threads = True socket = /var/www/html/myapp/myapp.sock chmod-socket = 660 vacuum = true die-on-term = true Again, everything seems to work fine except for when I try to initialize pymongo. Finally, my app's service file:
[Unit] Description=uWSGI Python container server After=network.target [Service] User=pi Group=www-data WorkingDirectory=/var/www/html/myapp ExecStart=/usr/bin/uwsgi --ini /etc/uwsgi/apps-available/myapp.ini [Install] WantedBy=multi-user.target 
