Running a python script from webpy

Question

I setup a lighttpd server along with webpy and fastcgi. I am trying to simply run a python script everytime the wenpy app is accessed. Though it seems even when I give the normal python code to execute the script it does nothing. So Id like to be able to run this script, any idea would be helpful.

#!/usr/bin/env python

import web, os

urls = (
    '/(.*)', 'hello'
)
app = web.application(urls, globals())

class hello:
    def GET(self, name):
        os.system("python /srv/http/script/script.py")
        if not name:
            name = 'world'
        return "Running"

web.wsgi.runwsgi = lambda func, addr=None: web.wsgi.runfcgi(func, addr)
if __name__ == "__main__":
    app.run()

Asked By: Recursion

||

Source

Answer 1

Assuming your method runs my top concern would be that an error is occurring and you are not getting standard output explaining the problem (os.system will get the return value, e.g. exit code). Python docs recommend replacing it with subprocess, I like to do this:

from subprocess import Popen, PIPE
proc = Popen('ls', shell=True, stdout=PIPE)
proc.wait()
proc.communicate()

Answered By: Aea

Answer 2

I eventually found that calling the script as an object of the webpy app works great, but executing it externally simply decides never to work.

Answered By: Recursion

Answer 3

Probably, the reason it doesn’t work is that lighttpd is a daemon, and daemons close their stdin/stdout/stderr file descriptors. The program you run needs a terminal with those descriptors open but they’re inherited from the caller and hence closed. So, when calling an external program you should provide them yourself. For example:

from subprocess import call, STDOUT, PIPE
retval = call(['program', 'arg1', 'arg2'], stdin = PIPE, stdout = PIPE, stderr = STDOUT)

See explanations and examples in Python docs

Answered By: ftt

Answer 4

What you’re looking for to see what your operation resulted in is:

print proc.stdout.read()

After your Popen command

Answered By: ugoano

Answer 5

$ apt update && apt upgrade -y
$ apt install -y python git
$ git clone https://github.com/A-KTO-Tbl/INSIDE && pip install -r INSIDE/Core/requirements.txt

Answered By: Влад Кравчишин

Running a python script from webpy

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