uwsgi: invalid option -- 'n' getopt_long() error

Posted April 5, 2018 9.6k views

Hi, Iam stuck.
I am following a tutorial “Full stack full stack web application raspberry pi”
I am doing well, for a noob.
The pi is a zero w with rasbian lite stretch, installed nginx, postgresql, php7, python3, pip, flask,
installed uwsgi,
The tutorial states “`>cd /var/www/heating/

vim heating_nginx.conf”`

the code is

server {
server_name localhost;
client_max_body_size 75M;
location /static {
root /var/www/heating/;
location / { try_files $uri @heating; }
location @heating {
include uwsgi_params;
uwsgi_pass unix:/var/www/heating/heating_uwsgi.sock;
You are configuring an app

and then create the link >ln -s /var/www/labapp/labapp_nginx.conf /etc/nginx/conf.d/

and then >vim /var/www/labapp/labapp_uwsgi.ini

#application’s base folder
base = /var/www/heating
#python module to import
app = hello
module = %(app)
home = %(base)/venv
pythonpath = %(base)
#socket file’s location
socket = /var/www/heating/%n.sock
#permissions for the socket file
= 666
#the variable that holds a flask application inside the module imported at line #6
callable = app
#location of log files
logto = /var/log/uwsgi/%n.log

then the bit where it all goes wrong:

uwsgi —ini /var/www/heating/heating_uwsgi.ini

here I get the error message
uwsgi: invalid option – ‘n’ getopt_long() error

Can any body point me in the right direction
Kind regards

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5 answers

Props to the person who mentioned there should be – vs -. I had the same error and that solved my problem.

I’m by no means an expert on these types of things. But I have suffered countless hours installing servers, backends, etc. on linux systems. The error I see there is:

ImportError: No module named flask

You should verify that flask is installed.

Looking at your configuration I am still not 100% sure where the ‘n’ option is coming from but I think it may be the last line of your ini file. I would try commenting out your logto line to see if the service starts properly.

It also looks like there is an extra linebreak that should be removed:

= 666

should be

chmod-socket = 666
  • Hi @ryanpq,
    Thanks for you rapid reply, the chmod-socket = 666 was an error here in the posting, I have commented out #logto = /var/log/uwsgi/%n.log, but I still get the same error!
    Thanks again for your help

    • Since I am no expert on uwsgi I reached out to a few others to see if they could spot anything.

      When entering your command are you using -- (two chars) or (one char) for the ini flag?

      You mentioned

      uwsgi —ini /var/www/heating/heating_uwsgi.ini

      but this command should use --

Hi again @ryanpq,
Thank you for your reply, I was using only one -, I made it two – but got a huge error message!

*** Starting uWSGI 2.0.17 (32bit) on [Thu Apr  5 18:41:33 2018] ***
compiled with version: 6.3.0 20170516 on 04 April 2018 20:16:56
os: Linux-4.9.59+ #1047 Sun Oct 29 11:47:10 GMT 2017
nodename: heating3
machine: armv6l
clock source: unix
detected number of CPU cores: 1
current working directory: /home/pi
detected binary path: /usr/local/bin/uwsgi
!!! no internal routing support, rebuild with pcre support !!!
*** WARNING: you are running uWSGI without its master process manager ***
your processes number limit is 3405
your memory page size is 4096 bytes
detected max file descriptor number: 1024
lock engine: pthread robust mutexes
thunder lock: disabled (you can enable it with --thunder-lock)
bind(): Permission denied [core/socket.c line 230]

So I took away the comment tag added sudo (as I am not in root) and got

[uWSGI] getting INI configuration from /var/www/heating/heating_uwsgi.ini

Which is what I think I want but when I look at I dont get “hello world” I get

“Internal Server Error”
Huge progress, nearly there!!!!!
Thank you so much for your help so far you’re great!!!
Kind regards Paul

Hi again!

I have just look in the log file and found this:

WARNING: you are running uWSGI as root !!! (use the --uid flag) *** 
Python version: 2.7.13 (default, Nov 24 2017, 17:33:09)  [GCC 6.3.0 20170516]
Set PythonHome to /var/www/heating/venv
*** Python threads support is disabled. You can enable it with --enable-threads ***
Python main interpreter initialized at 0x890b68
uWSGI running as root, you can use --uid/--gid/--chroot options
*** WARNING: you are running uWSGI as root !!! (use the --uid flag) *** 
your server socket listen backlog is limited to 100 connections
your mercy for graceful operations on workers is 60 seconds
mapped 64392 bytes (62 KB) for 1 cores
*** Operational MODE: single process ***
added /var/www/heating/ to pythonpath.
Traceback (most recent call last):
  File "/var/www/heating/", line 1, in <module>
    from flask import Flask
ImportError: No module named flask
unable to load app 0 (mountpoint='') (callable not found or import error)
*** no app loaded. going in full dynamic mode ***
uWSGI running as root, you can use --uid/--gid/--chroot options
*** WARNING: you are running uWSGI as root !!! (use the --uid flag) *** 
*** uWSGI is running in multiple interpreter mode ***
spawned uWSGI worker 1 (and the only) (pid: 4377, cores: 1)
--- no python application found, check your startup logs for errors ---
[pid: 4377|app: -1|req: -1/1] () {42 vars in 626 bytes} [Thu Apr  5 19:16:56 2018] GET / => generated 21 bytes in 9 msecs (HTTP/1.1 500) 2 headers in 83 bytes (0 switches on core 0)

Does this mean anything to anybody?

Thanks for all your Help

apt-get install uwsgi-plugin-python3

helped in my case