I am in Windows and Suppose I have a main python code that calls python interpreter in command line to execute another python script ,say test.py .
So test.py is executed as a new process.How can I find the processId for this porcess in Python ?
Update:
To be more specific , we have os.getpid() in os module. It returns the current process id.
If I have a main program that runs Python interpreter to run another script , how can I get the process Id for that executing script ?
If you used subprocess to spawn the shell, you can find the process ID in the pid property:
sp = subprocess.Popen(['python', 'script.py'])
print('PID is ' + str(sp.pid))
If you used multiprocessing, use its pid property:
p = multiprocessing.Process()
p.start()
# Some time later ...
print('PID is ' + str(p.pid))
It all depends on how you're launching the second process.
If you're using os.system or similar, that call won't report back anything useful about the child process's pid. One option is to have your 2nd script communicate the result of os.getpid() back to the original process via stdin/stdout, or write it to a predetermined file location. Another alternative is to use the third-party psutil library to figure out which process it is.
On the other hand, if you're using the subprocess module to launch the script, the resulting "popen" object has an attribute popen.pid which will give you the process id.
You will receive the process ID of the newly created process when you create it. At least, you will if you used fork() (Unix), posix_spawn(), CreateProcess() (Win32) or probably any other reasonable mechanism to create it.
If you invoke the "python" binary, the python PID will be the PID of this binary that you invoke. It's not going to create another subprocess for itself (Unless your python code does that).
Another option is that the process you execute will set a console window title for himself.
And the searching process will enumerate all windows, find the relevant window handle by name and use the handle to find PID. It works on windows using ctypes.
Related
I have a python script that launches subprocesses using subprocess.Popen. The subprocess then launches an external command (in my case, it plays an mp3). The python script needs to be able to interrupt the subprocesses, so I used the method described here which gives the subprocess its own session ID. Unfortunately, when I close the python script now, the subprocess will continue to run.
How can I make sure a subprocess launched from a script, but given a different session ID still closes when the python script stops?
Is there any way to kill a Thread in Python?
and make sure you use it as thread
import threading
from subprocess import call
def thread_second():
call(["python", "secondscript.py"])
processThread = threading.Thread(target=thread_second) # <- note extra ','
processThread.start()
print 'the file is run in the background'
TL;DR Change the Popen params: Split up the Popen cmd (ex. "list -l" -> ["list", "-l"]) and use Shell=False
~~~
The best solution I've seen so far was just not to use shell=True as an argument for Popen, this worked because I didn't really need shell=True, I was simply using it because Popen wouldn't recognize my cmd string and I was too lazy too split it into a list of args. This caused me a lot of other problems (ex. using .terminate() becomes a lot more complicated while using shell and needs to have its session id, see here)
Simply splitting the cmd from a string to a list of args lets me use Popen.terminate() without having to give it its own session id, by not having a separate session id the process will be closed when the python script is stopped
I've got a long running python script that I want to be able to end from another python script. Ideally what I'm looking for is some way of setting a process ID to the first script and being able to see if it is running or not via that ID from the second. Additionally, I'd like to be able to terminate that long running process.
Any cool shortcuts exist to make this happen?
Also, I'm working in a Windows environment.
I just recently found an alternative answer here: Check to see if python script is running
You could get your own PID (Process Identifier) through
import os
os.getpid()
and to kill a process in Unix
import os, signal
os.kill(5383, signal.SIGKILL)
to kill in Windows use
import subprocess as s
def killProcess(pid):
s.Popen('taskkill /F /PID {0}'.format(pid), shell=True)
You can send the PID to the other programm or you could search in the process-list to find the name of the other script and kill it with the above script.
I hope that helps you.
You're looking for the subprocess module.
import subprocess as sp
extProc = sp.Popen(['python','myPyScript.py']) # runs myPyScript.py
status = sp.Popen.poll(extProc) # status should be 'None'
sp.Popen.terminate(extProc) # closes the process
status = sp.Popen.poll(extProc) # status should now be something other than 'None' ('1' in my testing)
subprocess.Popen starts the external python script, equivalent to typing 'python myPyScript.py' in a console or terminal.
The status from subprocess.Popen.poll(extProc) will be 'None' if the process is still running, and (for me) 1 if it has been closed from within this script. Not sure about what the status is if it has been closed another way.
This worked for me under windows 11 and PyQt5:
subprocess.Popen('python3 MySecondApp.py')
Popen.terminate(app)
where app is MyFirstApp.py (the caller script, running) and MySecondApp.py (the called script)
I'm working with Iot on the Intel Galileo with a Yocto image, I have it that a python script will execute 'aplay audio.wav', But I want it to also get the PID of that aplay proccess in case the program will have to stop it. Sorry for being very short and brief.
The pid attribute of the subprocess.Popen object contains its PID, but if you need to terminate the subprocess then you should just use the terminate() method.
You should consider using pyao or pygst/gst-python instead though, if you need finer control over audio.
With Python use:
import os
my_pid = os.getpid()
f_pid = open('/var/run/app.pid', 'w')
f_pid.write(my_pid)
f_pid.close()
But if you are using the play, you're doing syscall() for Python? You can do directly by Shell Script and get the PID easily with:
echo $! > /var/run/$0.pid
You can read the file.pid and send a kill for the PID.
Under Linux Ubuntu operating system, I run the test.py scrip which contain a GObject loop using subprocess by:
subprocess.call(["test.py"])
Now, this test.py will creat process. Is there a way to kill this process in Python?
Note: I don't know the process ID.
I am sorry if I didn't explain my problem very clearly as I am new to this forms and new to python in general.
I would suggest not to use subprocess.call but construct a Popen object and use its API: http://docs.python.org/2/library/subprocess.html#popen-objects
In particular:
http://docs.python.org/2/library/subprocess.html#subprocess.Popen.terminate
HTH!
subprocess.call() is just subprocess.Popen().wait():
from subprocess import Popen
from threading import Timer
p = Popen(["command", "arg1"])
print(p.pid) # you can save pid to a file to use it outside Python
# do something else..
# now ask the command to exit
p.terminate()
terminator = Timer(5, p.kill) # give it 5 seconds to exit; then kill it
terminator.start()
p.wait()
terminator.cancel() # the child process exited, cancel the hit
subprocess.call waits for the process to be completed and returns the exit code (integer) value , hence there is no way of knowing the process id of the child process. YOu should consider using subprocess.Popen which forks() child process.
I am using a build system(waf) which is a wrapper around python. There are some programs(perl scripts,exe's etc) calling the python build system. When I execute the build scripts from cmd.exe, I need to find out the program that called it. My OS is windows 7. I tried getting the parent PID in a python module and it returns "cmd" as PPID and "python.exe" as PID, so that approach did not help me in finding what I am looking for.
I believe I should be looking at some stacktraces on a OS level, but am not able to find how to do it. Please help me with the approach I should take or a possible code snippet. I just need to know the name of the script or program that called the system, example caller.perl, callload.exe
Thank you
Though I am not sure why it would be needed but this is a fun problem in itself, so here are few tips, once you have parent PID loop thru processes and get name e.g.
using WMI
import wmi
c = wmi.WMI ()
for process in c.Win32_Process ():
if process.ProcessId == ppid:
print process.ProcessId, process.Name
I think you can do same thing using win32 API, e.g.
processes = win32process.EnumProcesses()
for pid in processes:
if pid == ppid:
handle = win32api.OpenProcess(win32con.PROCESS_ALL_ACCESS,
False, pid)
exe = win32process.GetModuleFileNameEx(handle, 0)
This will work for simple cases when progA directly executes progB but if there is a long chain of child process in between, it may not be good solution. Best way for a generic case would be for calling program to tell his identity by passing it as argument e.g.
progB --calledfrom progA
modify the python script to add an argument to it, stating which file called it. then log it into a logger file. all scripts calling it will have to identify themselves to the python script via the argument vector.
For example:
foo.pl calls yourfile.py as:
yourfile.py /path/to/foo.pl
yourfile.py:
def main(argv):
logger.print(argv[1])
I was able to use process explorer to see the chain of processes called and was able to retrieve the name by just traversing the parent. Thanks for all who replied.