Processes in Linux from Python

[Johny]

To get a number of the http processes running on my Linux( Debia box)
I use
ps -ef | grep "[h]ttpd" | wc -l

But If I want to use to get a number of the http processes from my
Python program I must use a popen command e.g.
popen2.popen3(' ps -ef | grep "[h]ttpd" | wc -l')
that is I must call an external command from Python.

But it creates a zombie.
So my question is:
Is it possible to get a number of the http processes running on Linux
directly from Python ?

Thanks for help.
L.

[Diez B. Roggisch]

Re: Processes in Linux from Python

Johny schrieb:

To get a number of the http processes running on my Linux( Debia box)
I use
ps -ef | grep "[h]ttpd" | wc -l
>
But If I want to use to get a number of the http processes from my
Python program I must use a popen command e.g.
popen2.popen3(' ps -ef | grep "[h]ttpd" | wc -l')
that is I must call an external command from Python.

The shell does the exact same thing. And by the way: i think you miss a

grep -v grep

after the first grep - otherwise you count the grep itself.

But it creates a zombie.

Try using the subprocess module. It should not require you to call wait
yourself.

So my question is:
Is it possible to get a number of the http processes running on Linux
directly from Python ?

Not really, or at least not with less effort & without duplicating
system tools functionality.

Diez

[Christian Heimes]

Re: Processes in Linux from Python

Johny wrote:

Is it possible to get a number of the http processes running on Linux
directly from Python ?

The Python core has no direct API for the job. However you can use the
virtual /proc/ file system for the job. Or check out my enumprocess
package.

http://pypi.python.org/pypi?:action=display&name=enumprocess&version=0.1

It's far from perfect but it should do the job on Linux.

Christian

[Wojtek Walczak]

Re: Processes in Linux from Python

On Sun, 31 Aug 2008 23:25:56 -0700 (PDT), Johny wrote:

To get a number of the http processes running on my Linux( Debia box)
I use
ps -ef | grep "[h]ttpd" | wc -l

....

So my question is:
Is it possible to get a number of the http processes running on Linux
directly from Python ?

Yes, it is. There is a number of third party packages that provide
such functionality, including PSI: http://www.psychofx.com/psi/
I never actually liked them, because they are parsing /proc directory
by themselves. Thus I wrote my own tool that is a wrapper around
procps library (libproc* in your /lib, probably). Your system tools
like ps, w or top are using this library. My wrapping library is
available at: http://code.google.com/p/procpy/
In your case you could use it like this:

>>import procpy
>>pp = procpy.Proc()
>>for pid in pp.pids:

.... if pp.procs[pid]['cmd'] == 'apache2':
.... print pp.procs[pid]['tid']
....
5204
5205
5206
5208

>>>

it prints the PIDs of all the apache2 processes on my system.
Procpy is fine for my own needs, but if I were about to write
a code that is intended to be portable, I'd use PSI. It also is
more mature.

--
Regards,
Wojtek Walczak,

http://tosh.pl/gminick/

[Derek Martin]

Re: Processes in Linux from Python

On Mon, Sep 01, 2008 at 08:40:42AM +0200, Diez B. Roggisch wrote:

Johny schrieb:

To get a number of the http processes running on my Linux( Debia box)
I use
ps -ef | grep "[h]ttpd" | wc -l

[...]

The shell does the exact same thing. And by the way: i think you miss a
>
grep -v grep

Indeed not. The brackets around the 'h' (which make it a character
class, or range if you prefer) prevent the regex from matching itself.

--
Derek D. Martin

http://www.pizzashack.org/

GPG Key ID: 0x81CFE75D


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