Questions[virtualenv](server)

I have a python script that I normally run it with this command:

(environment) python run.py

I want to run this script at start. (I'm using ubuntu) Here is my service:

[Unit]
Description=My Script Service
After=multi-user.target

[Service]
Type=idle

ExecStart=/home/user/anaconda3/bin/python /home/user/space/run.py

[Install]
WantedBy=multi-user.target

BTW, I couldn't run this script, but I could run any script that is not inside environment. How can I run a python script at startup (virtualenv)?

sudo systemctl status user_sent
● user_sent.service - Mail Service
Loaded: loaded (/lib/systemd/system/user_sent.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since xxxxx 16:30:20 MSK; 3s ago
Process: 3713 ExecStart=/usr/bin/python run.py (code=exited,   status=200/CHDIR)
Main PID: 3713 (code=exited, status=200/CHDIR)

I'm planning to set up a Python app (Pyblosxom) on my server and considering to run it in its own virtualenv sandbox with --no-site-packages. I'm hoping that such a setup would be easily portable and maintainable over the years.

However, I've only used virtualenv for development environments that recreate a certain server setup locally, and most sources about virtualenv seem to also mention virtualenv for such a use.

Is there any drawback to running a Python app from a virtualenv on a live server?

NOTE: As for the portability of the setup, I've just been made aware of the experimental --relocatable option which needs to be ran after new package installs. Even if I didn't do this though, I guess the setup would be quite portable thanks to pip.

I got nginx + uWSGI running on localhost inside a virtualenv with a simple hello world program, but I get this error when I replace the hello world with a simple Flask app:

File "./wsgi_configuration_module.py", line 1, in <module>
    from flask import Flask
ImportError: No module named flask
unable to load app mountpoint

Here's the flask app (wsgi_configuration_module.py):

from flask import Flask
application = Flask(__name__)

@application.route("/")
def hello():
    return "hello world"

if __name__ == "__main__":
    application.run()

uWSGI config (app_conf.xml):

<uwsgi>
    <socket>127.0.0.1:9001</socket>
    <chdir>/srv/www/labs/application</chdir>
    <pythonpath>/srv/www</pythonpath>
    <module>wsgi_configuration_module</module>
    <callable>application</callable>
    <no-site>true</no-site>
</uwsgi>

nginx config:

server {
    listen   80;
    server_name localhost;
    access_log /srv/www/labs/logs/access.log;
    error_log /srv/www/labs/logs/error.log;

    location / {
        include        uwsgi_params;
        uwsgi_pass     127.0.0.1:9001;
    }

    location /static {
        root   /srv/www/labs/public_html/static/;
        index  index.html index.htm;
    }
}

virtualenv stored in ~/virtual_env with Python 2.7 + nginx + uWSGI + Flask installed in a virtualenv called basic.

Things I've tried to solve this:

1. set the --home (-H) option to my virtualenv folder ~/virtual_env while running uWSGI.

Other info:

1. I have the same setup working outside of a virtualenv. Things go wrong only when I try to replicate the setup inside of a virtualenv.

Where have I gone wrong?

I've setup and tested celery on my amazon linux server, using mysql as the messaging backend and it works fine when running the program directly. My python project and celery install are located in a virtualenv. However if I attempt to daemonize celery by using the script here, the program refuses to run in the background.

I'm passing the virtualenv installed location of celery to the daemon in the config file using CELERYD="/opt/apps/myenv/[path to celeryd]" which equates to using the flag --cmd when starting celeryd.

The script always stops after starting worker node 1 and waits, as if I'm running the program directly and not daemonizing it. Celery is active at this point but stops after I close the terminal window or press ctrl-c.

I've tried running it without the --cmd, and it seems to run in the background, but the workers won't start, and calling stop returns an 'unknown instance'.

Any suggestions would be appreciated.

I have a strange issue with my virtualenv + gunicorn setup, only when gunicorn is launched via supervisord. I do realize that it may very well be an issue with my supervisord and I would appreciate any feedback on a better place to ask for help...

In a nutshell : when I run gunicorn from my user shell, inside my virtualenv, everything is working flawlessly. I'm able to access all the views of my Django project.

When gunicorn is launched by supervisord at the system startup, everything is OK.

But, if I have to kill the gunicorn_django processes, or if I perform a supervisord restart, once that gunicorn_django has relaunched, every request is answered with a weird Traceback :

(...)
  File "/home/hc/prod/venv/lib/python2.6/site-packages/Django-1.2.5-py2.6.egg/django/db/__init__.py", line 77, in
    connection = connections[DEFAULT_DB_ALIAS]
  File "/home/hc/prod/venv/lib/python2.6/site-packages/Django-1.2.5-py2.6.egg/django/db/utils.py", line 92, in __getitem__
    backend = load_backend(db['ENGINE'])
  File "/home/hc/prod/venv/lib/python2.6/site-packages/Django-1.2.5-py2.6.egg/django/db/utils.py", line 50, in load_backend
    raise ImproperlyConfigured(error_msg)
TemplateSyntaxError: Caught ImproperlyConfigured while rendering: 'django.db.backends.postgresql_psycopg2' isn't an available database backend.
Try using django.db.backends.XXX, where XXX is one of:
    'dummy', 'mysql', 'oracle', 'postgresql', 'postgresql_psycopg2', 'sqlite3'
Error was: cannot import name utils

Full stack available here : http://pastebin.com/BJ5tNQ2N

I'm running...

• Ubuntu/maverick (up-to-date)
• Python = 2.6.6
• virtualenv = 1.5.1
• gunicorn = 0.12.0
• Django = 1.2.5
• psycopg2 = '2.4-beta2 (dt dec pq3 ext)'

gunicorn configuration :

backlog = 2048
bind = "127.0.0.1:8000"
pidfile = "/tmp/gunicorn-hc.pid"
daemon = True
debug = True
workers = 3
logfile = "/home/hc/prod/log/gunicorn.log"
loglevel = "info"

supervisord configuration :

[program:gunicorn]
directory=/home/hc/prod/hc
command=/home/hc/prod/venv/bin/gunicorn_django -c /home/hc/prod/hc/gunicorn.conf.py
user=hc
umask=022
autostart=True
autorestart=True
redirect_stderr=True

Any advice ? I've been stuck on this one for quite a while.

It seems like some weird memory limit, as I'm not enforcing anything special :

$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 20
file size               (blocks, -f) unlimited
pending signals                 (-i) 16382
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) unlimited
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited