Is there a module can be used as FindWindow API in python - python

On Windows there is a WinAPI: FindWindow that you can use to get window handle of a existing window and use this handle to send message to it. Is there a python module can do that too? Find a window & communicate with it?
If this module do exist, could the same mechainsm be able applied on Ubuntu too?
Thanks a lot!

You can execute your commands with a subprocess:
import subprocess
import time
process = subprocess.Popen("echo 'start' & sleep 60 & echo 'stop'", shell=True)
time.sleep(60) # Maybe you want a timer...
The you have two options of closing, use terminate or kill methods in the Popen returned object or simulate a Ctrl. + C
import subprocess
import time
process = subprocess.Popen(cmd, shell=True)
time.sleep(5)
process.terminate() # Or kill
Simulate de ctrl + c:
import subprocess
import time
import os
import signal
process = subprocess.Popen(cmd, shell=True)
time.sleep(5)
os.kill(process.pid, signal.SIGINT) # Ctrl. + C
If you want to get the output you can use:
process.communicate()[0].strip()
Which gives you a string.
If you want a console GUI, you can use a command like:
gnome-terminal -x sh yourCommand
Or the equivalent for the terminal you have installed.

Related

Live output from Python subprocess that calls Python script

There's quite a bit of posts related to collecting live output from a process that was launched using Python's subprocess module. When I attempt these solutions between my two test scripts, one being a (ba)sh script and the other being a Python script, the Python script fails to have its output read live. Instead when the Python script is ran by subprocess it ends up waiting until the process has completed to flush it to PIPE. The constraints I'm bounded by is that I do want a way to retrieve live output from subprocess for the Python script.
Tested on Ubuntu 20.04 & Windows, Shell script ran on Ubuntu 20.04.
Calling code:
import shlex
import subprocess
# invoke process
process = subprocess.Popen('python test.py',shell=True,stdout=subprocess.PIPE) #Shell true/false results in "not live" output
# Poll process.stdout to show stdout live
while True:
output = process.stdout.readline() # <-- Hangs here on calling test.py, doesn't hang on test.sh
if process.poll() is not None:
break
if output:
print(output.strip())
rc = process.poll()
test.py <-- Waits until it has completed to print out entire output
import time
for x in range(10):
print(x)
time.sleep(1)
test.sh <-- Prints out live in Python script
#!/bin/bash
for i in $(seq 1 5); do
echo "iteration" $i
sleep 1
done
#stochastic13 Provided a very useful link where the -u switch and PYTHONUNBUFFERED variable being set would work. For my needs, I used PYTHONUNBUFFERED which solved my issue entirely. The Python test script actually executes another Python script to run, which I needed the output on. Despite -u helping for the first script, it wouldn't help for the second as I wouldn't have direct access to said script to add the argument. Instead I went with the environment variable, solution below:
def run_command(command):
os.environ['PYTHONUNBUFFERED'] = '1'
process = Popen(command, shell=False, stdout=PIPE, env=os.environ) # Shell doesn't quite matter for this issue
while True:
output = process.stdout.readline()
if process.poll() is not None:
break
if output:
print(output)
rc = process.poll()
return rc
Above the code passes PYTHONUNBUFFERED and sets it to the environment, any spawned process in subprocess with this environment set will inherit PYTHONUNBUFFERED.
Test Script
import subprocess
from io import TextIOWrapper, TextIOBase, StringIO
from subprocess import PIPE, Popen, call
from tempfile import TemporaryFile
from sarge import run, Capture
# process = Popen('python test2.py', shell=False)
# while True:
# if process.poll() is not None:
# break
# rc = process.poll()
subprocess.call('python test2.py')
Test Script 2
import time
import os
print(list(os.environ.keys()))
for x in range(10):
print('test2', x)
time.sleep(1)
The output is a live capture of stdout from any Python process, not just after completion.
...
b'test2 0\r\n'
b'test2 1\r\n'
b'test2 2\r\n'
b'test2 3\r\n'
...
0

kill process do not kill the subprocess and do not close a terminal window

I am working on UBUNTU and I have file main.py with a code inside:
#!/usr/bin/env python3
# coding=utf-8
import os
import time
from subprocess import Popen, PIPE, call, signal
base_path = os.path.abspath('')
path_to_file = base_path + '/test_subprocess.py'
p = Popen(['gnome-terminal', "--", path_to_file])
time.sleep(2)
os.kill(p.pid, signal.SIGKILL)
I have test_subprocess.py with code like that:
#!/usr/bin/env python3
# coding=utf-8
import time
def print_message():
while True:
print('I am working!')
time.sleep(0.5)
print_message()
I tried to kill the subprocess but after
os.kill(p.pid, signal.SIGKILL)
subprocess is still working and prints 'I am working!'
How can I finish subprocess and how to close gnome terminal?
If I selected completely wrong way. Can you show me working example?
New version of test_subprocess.py
#!/usr/bin/env python3
# coding=utf-8
import sys
from subprocess import signal
import time
def print_message():
while True:
print('I am working!')
time.sleep(0.5)
if signal.SIGKILL: # it is braking a loop when parent process terminate!
print('I am killing self!')
break
print_message()
Should I do it like above?
You could try the following:
p = Popen(['gnome-terminal', "--", path_to_file])
PIDs = p.pid
os.system("kill {0}".format(PIDs))
Popen.pid The process ID of the child process.
Note that if you set the shell argument to True, this is the process
ID of the spawned shell.
http://docs.python.org/library/subprocess.html
This will at least kill the correct process. Not sure if it will close the terminal.
Edit: to kill the process and close the terminal:
p = Popen(['gnome-terminal', '--disable-factory', '-e', path_to_file], preexec_fn=os.setpgrp)
os.killpg(p.pid, signal.SIGINT)
Credit to https://stackoverflow.com/a/34690644/15793575, whih I modified for your command:
--disable-factory is used to avoid re-using an active terminal so that we can kill newly created terminal via the subprocess handle
os.setpgrp puts gnome-terminal in its own process group so that
os.killpg() could be used to send signal to this group
Popen.pid
The process ID of the child process.
Note that if you set the shell argument to True, this is the process
ID of the spawned shell.
Try setting the shell argument of the Popen constructor to False. (p = Popen(['gnome-terminal', "--", path_to_file]) -> p = Popen(['gnome-terminal', "--", path_to_file], shell=False)). I had a similar issue not long ago - this fixed it for me.

How to get the pid of the process started by subprocess.run and kill it

I'm using Windows 10 and Python 3.7.
I ran the following command.
import subprocess
exeFilePath = "C:/Users/test/test.exe"
subprocess.run(exeFilePath)
The .exe file launched with this command, I want to force-quit when the button is clicked or when the function is executed.
Looking at a past question, it has been indicated that the way to force quit is to get a PID and do an OS.kill as follows.
import signal
os.kill(self.p.pid, signal.CTRL_C_EVENT)
However, I don't know how to get the PID of the process started in subprocess.run.
What should I do?
Assign a variable to your subprocess
import os
import signal
import subprocess
exeFilePath = "C:/Users/test/test.exe"
p = subprocess.Popen(exeFilePath)
print(p.pid) # the pid
os.kill(p.pid, signal.SIGTERM) #or signal.SIGKILL
In same cases the process has children
processes. You need to kill all processes to terminate it. In that case you can use psutil
#python -m pip install —user psutil
import psutil
#remember to assign subprocess to a variable
def kills(pid):
'''Kills all process'''
parent = psutil.Process(pid)
for child in parent.children(recursive=True):
child.kill()
parent.kill()
#assumes variable p
kills(p.pid)
This will kill all processes in that PID

How to kill a subprocess in python

I have code which runs a webcamera on a linux pc using the gst-launchcommand.
When I kill the process, the webcamera window does not turn off, but the program stops running. I want the webcamera window also to be closed.
Can you help me on this?
import subprocess
import time
import os
import signal
cmd = "gst-launch-1.0 -v v4l2src ! video/x-raw,format=YUY2 ! videoconvert ! autovideosink"
process = subprocess.Popen(cmd, shell = True)
time.sleep(5)
#print(subprocess.Popen.pid)
#process.terminate()
os.kill(process.pid, signal.SIGKILL)
#process.kill()
Hope it will help you.
import os
import signal
import subprocess
process = subprocess.Popen(cmd, shell = True)
os.killpg(os.getpgid(process.pid), signal.SIGTERM)
For me, the currently accepted answer will terminate the main program as well. If you experience the same problem and want it to continue, you will have to also add the argument preexec_fn=os.setsid to popen. So in total:
import os
import signal
import subprocess
process = subprocess.Popen(cmd, shell=True, preexec_fn=os.setsid)
os.killpg(os.getpgid(process.pid), signal.SIGTERM)
I got this from here: https://stackoverflow.com/a/4791612/11642492

Can I close the CMD window that opened with subprocess.Popen in Python?

I have a program that need to run small tasks in new CMDs.
For example:
def main()
some code
...
proc = subprocess.Popen("start.bat")
some code...
proc.kill()
subprocess,Popen opens a new cmd window and runs "start.bat" in it.
proc.kill() kills the process but doesn't close the cmd window.
Is there a way to close this cmd window?
I thought about naming the opened cmd window so i can kill it with the command:
/taskkill /f /im cmdName.exe
Is it possible ?if no, What do you suggest ?
Edit, Added Minimal, Complete, and Verifiable example:
a.py:
import subprocess,time
proc = subprocess.Popen("c.bat",creationflags=subprocess.CREATE_NEW_CONSOLE)
time.sleep(5)
proc.kill()
b.py
while True:
print("IN")
c.bat
python b.py
that's expected when a subprocess is running. You're just killing the .bat process.
You can use psutil (third party, use pip install psutil to install) to compute the child processes & kill them, like this:
import subprocess,time,psutil
proc = subprocess.Popen("c.bat",creationflags=subprocess.CREATE_NEW_CONSOLE)
time.sleep(5)
pobj = psutil.Process(proc.pid)
# list children & kill them
for c in pobj.children(recursive=True):
c.kill()
pobj.kill()
tested with your example, the window closes after 5 seconds
here is another way you can do it
import subprocess
from subprocess import Popen,CREATE_NEW_CONSOLE
command ='cmd'
prog_start=Popen(command,creationflags=CREATE_NEW_CONSOLE)
pidvalue=prog_start.pid
#this will kill the invoked terminal
subprocess.Popen('taskkill /F /T /PID %i' % pidvalue)

Categories