[Tutor] checking for a process

[John Moylan]

This looked like a usefull but really dirty hack at first, on on later
inspection - it will probably have the effect of not allowing the script
to run if the same file is open in an editor or in less somewhere else
on the system.

so I wrote the following class to check /proc to see if a process is
running:

class IsPidRunning:
    def __init__(self,pidfile="/var/run/enc.pid"):
        self.pidfile = pidfile

    def set_pidfile(self,pidfile):
        self.pidfile = pidfile

    def doesitexist(self):
        if  os.path.exists(self.pidfile):
            pidf = open(self.pidfile, 'r')

            if os.path.exists('/proc/'+pidf.read()):
                print "Script already running"
                sys.exit()
            else: self.writepid()
        else: self.writepid()

    def writepid(self):
        pidf = open(self.pidfile, 'w')
        pid = os.getpid()
        print pid
        pidf.write(str(pid))
        pidf.close()


John


On Wed, 2003-08-27 at 09:55, David Dorgan wrote:
> Quoting John Moylan (john at rte.ie):
> > The problem is that I don't want to have to create a BASH wrapper script 
> > around my python script ....but I can't find any way of finding out if a 
> > process is running ala the ps bit of my script above...without spawning a 
> > shell. Is there any way to do this natively in Python? or is there a better 
> > way of creating the same functionality in Python? 
> 
> 
> If you want a real awful hack, but probably
> a little better than what you have, use popen2,
> run ps aux | grep -v grep | grep -c whatever  
> 
> if the return is greater than 0, it's running,
> else, run it.
-- 
John Moylan
----------------------
Radio Telefis Eireann,
Donnybrook,
Dublin 4,
Eire
t:+353 1 2083564
e:john.moylan at rte.ie



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