How to stop cherrypy auto-reload from changing the process name on Debian?

Question

I am developing a project using cherrypy, on debian. At my work, the administrators want to see the name of the project instead of "python" displayed when using commands like ps -e. However, when cherrypy auto-reloads when modifying one source file, it automatically changes the process name.

For example, if I take the most basic cherrypy tutorial and save it under NameToSee.py:

#!/usr/bin/python
import cherrypy


class HelloWorld(object):
    @cherrypy.expose
    def index(self):
        return "Hello world!"

if __name__ == '__main__':
   cherrypy.quickstart(HelloWorld())

By adding the shebang at the start, when I launch it $ ./NameToSee.py &, I get a process (say 31051) whose name is "NameToSee.py":

$ head /proc/31051/status
Name:   NameToSee.py
State:  S (sleeping)

However, whenever I change the source code files (for example, by adding an empty line), the process name changes:

$ head /proc/31051/status
Name:   python
State:  S (sleeping)

So, my question is: Can I get both cherrypy auto-reload and custom process name ? If not, can I remove the cherrypy auto-reload?

I am running on debian wheezy, with python 2.7.3 and cherrypy 3.2.2

score 2 · Accepted Answer · answered Dec 15 '15 at 19:47

This sample covers both cases:

import cherrypy
from cherrypy.process.plugins import SimplePlugin

PROC_NAME = 'sample'


def set_proc_name(newname):
    """                                                                                                                                                                                                      
    Set the process name.                                                                                                                                                                                    
    Source: http://stackoverflow.com/a/923034/298371                                                                                                                                                         
    """
    from ctypes import cdll, byref, create_string_buffer
    libc = cdll.LoadLibrary('libc.so.6')
    buff = create_string_buffer(len(newname)+1)
    buff.value = newname
    libc.prctl(15, byref(buff), 0, 0, 0)


class NamedProcess(SimplePlugin):
    """                                                                                                                                                                                                      
    Set the name of the process everytime that the                                                                                                                                                           
    engine starts.                                                                                                                                                                                           
    """

    def start(self):
        self.bus.log("Setting the name as '{}'".format(PROC_NAME))
        set_proc_name(PROC_NAME)


class HelloWorld(object):

    @cherrypy.expose
    def index(self):
        return "Hello world!"


def run_without_autoreload():
    set_proc_name(PROC_NAME)
    cherrypy.quickstart(HelloWorld(), config={
        'global': {
            'engine.autoreload.on': False
        }
    })


def run_with_autoreload():
    # Work on any configuration but for the sake of the                                                                                                                                                      
    # question this works with the autoreload.                                                                                                                                                               
    NamedProcess(cherrypy.engine).subscribe()
    cherrypy.quickstart(HelloWorld())


if __name__ == '__main__':
    run_with_autoreload()
    # run_without_autoreload()

You can test it with:

cat /proc/`pgrep  sample`/status

(or maybe just use pgrep)

And as a final recommendation consider using the "production" environment (see the docs) which also included the disabling of the autoreload plugin.

That sounds great. Do you know if there's any way to get PR_SET_NAME value dynamically instead of having a magic number in the code? — DainDwarf, Dec 16 '15 at 08:10

How to stop cherrypy auto-reload from changing the process name on Debian?

1 Answers1