It sounds like riddle or joke but actually I havent found answer to this problem.
What is actually the problem?
I want to run 2 scripts. In first script I call another script but I want them to continue parallely and not in 2 separate threads. Mainly I dont want 2nd script to be running inside 1st python script(That means if I run Chrome Browser from python script and then shut down the python script, the Chrome will be shut down too).
What I want is like on Linux machine: I open two terminals and run both scripts in each terminal - They are not two threads, they are independent on each other, shutting one will NOT shut down the other. Or it can be like on Linux machine where I can run 2 python scripts in terminal behind background with 'python xxx.py &' (&) symbol.
Summary:
I would like to run inside 'FIRST.py' script 'SECOND.py' script. However not with threading module and mainly have SECOND.py script independent on FIRST.py script, that is, shutting down FIRST.py will not have any consequence on SECOND.py.
THE SOLUTION SHOULD BE WORKING ON WINDOWS, LINUX AND MAC.
BTW:
I tried on windows:
subprocess.call(['python','second.py','&'])
subprocess.call(['python','second.py'])
os.system('python second.py') # I was desperate
They run serially, so first.py script is blocked untill second.py finishes.
I havent try Threading with daemon=False but I feel its kind of Demon and I dont feel my skill is that far that I can control threads existing outside of my playground :)
Thanks in advance for help
You can use the Popen constructor from the subprocess module to launch background processes, using
import subprocess
p = subprocess.Popen(["python","second.py"])
creates a background process and execution of first.py is not blocked.
Related
I'm trying to start two Python scripts that will run in an infinite loop.
The first script scrapes a webpage and dumps it into a CSV file.
The second script reads that CSV file and displays it on a webpage through Dash (localhost webserver).
With everything I've tried so far, it will run one script and wait for it to end before running the next (which doesn't work for me).
The only thing that has worked for me so far (which isn't optimal for production) is opening two Command Prompts and manually running each script in separate windows.
I've tried two buttons in PyQt.
I've tried a simple batch script (I'm on a Windows7 machine) with structure:
python file1.py &
python file2.py &
The functionality I need:
"Whilst the first script is scraping and dumping the web page, the other is at the same time reading and displaying it."
You can use start to launch both commands:
#echo off
start /b python file1.py
start /b python file2.py
A few notes about this: The commands will launch, but will not block the exit of the batch file, so unless you'll need to keep the command prompt open. Also, to kill them, use Ctrl-Break to stop the background processes.
It might be cleaner to use Python's multiprocessing to run the scripts, either as part of one of the scripts, or with a wrapper script, but that depends on your exact needs.
So you want to run file2.py after file1.py is completely finished its job?
If so, you can replace & with && so it would be something like this:
python file1.py && python file2.py
I wrote a python script that run an infinite loop and every half second checks if there are new files in a directory:
while True:
files = os.listdir(path_to_dir)
# do something
time.sleep(0.5)
The code runs on windows 10 in a cmd window and I need to make sure it will never stop.
A) I need to find a mechanism (or few mechanisms) that will restart the script in all possible scenarios that it might turn off (it is ok if the restart will happen only 2 minutes later...):
if the computer is restarting
if someone close the cmd windows
if the script end unexpectedly because of unhandle exception or memory leak (it is not suppose to happen...)
B) I want that once in a week, proactively,the script will be turn off and restart.
Any ideas?
Thanks!!
p.s. my first idea was that the python script will only check for new file, and the task scheduled will run it every second, but the minimum interval for task scheduler is 1 minute.
I think these answer all your questions:
Since your script runs on windows, you can use the Microsoft Task Scheduler (which is installed with Windows) to start your Python script when your computer starts up.
If you do not use the cmd window, you can change your Python script extention from .py to .pyw to run the script without a terminal window. A bit more on that here: Executing scripts.
For opening the script after an exception has happend, have a look at this blog post: How to Restart Python Script after Exception and Run it Forever.
To restart your script once a week, you can also use the Task Scheduler mentioned in answer 1. I think this post could help you with restarting your script: Start and stop a python task
I am trying to set up daemontools with a large python program that spawns various subprocesses, and I'm having issues where the subprocesses are not spawning correctly. The subprocess just appears as a zombified process when launched via daemontools.
I have provided a simplified example to demonstrate this.
/service/test/run:
#!/bin/sh
cd /script_directory/
exec envdir /service/test/env /usr/bin/python3 test_subprocess.py
/script_directory/test_subprocess.py
import subprocess
from time import sleep
subprocess.Popen("xterm")
while True:
sleep(1)
test_subprocess.py simply launches a GUI terminal and stays alive, so I can see if it is still running in top/htop.
If I run the script either as root or a non-root user, the script properly executes and the window is displayed. When run via daemontools/supervise, the xterm is zombified and no window is shown.
Setting the env/DISPLAY and env/XAUTHORITY variables as described here doesn't seem to work for me.
On further investigation, the subprocess is zombified even if it does not use the GUI. For example if the subprocess in subprocess.py is "top" - it will not run.
I've used daemontools successfully on various other projects that don't spawn subprocesses so I don't think the issue is with the basic setup here.
Can daemontools be used with scripts that spawn other processes?
If not, what some other recommended tools for daemonising complex python applications?
bro i can't understand what you went to do. but try this program:
import subprocess
p = subprocess.Popen(
['xterm', '-hold'], stdin=subprocess.PIPE)
p.communicate()
if went to give some argument use -e and type command,and if another problem please let me know.thanks
On windows:
I have two scripts:
Client.py
Console.py
Q1:
Client can be run multiple times but only single instance should be left running. It is being run with pythonW.exe
Q2:
Multiple console.py can be run at the same time. But the last one that closes should kill the client.py
Limitations:
Strongly preferred not to write any files. (i.e. use search by window name, PID etc...)
Strongly preferred not to install any additional modules for python. i.e. use ctypes etc...
For Q1 i tried to do ctypes.windll.user32.SetWindowTextA ("NAME") and then search for it. it works for python.exe but not for pythonW.exe beacause there is no console window then.
Thanks!
I would like to write a python script that will finally be converted to .exe (with pyinstaller lets say) and added to windows startup applications list. This program (once launched) should 'monitor' user and wait until user will start a specified program (say program1.exe) and then my python program should launch another specified program (program2.exe).
I know that there is something like subprocess to launch another program from python script but I was not able to make it work so far ;/ And as it comes to this part where I need to monitor if user does start specified program I have no idea haw to bite on this. I don't expect a complete solution (although it would be very nice to find such ;p) but any guides or clues would be very helpfull.
For the monitoring whether or not the user has launched the program, I would use psutil: https://pypi.python.org/pypi/psutil
and for launching another program from a python script, I would use subprocess.
To launch something with subprocess you can do something like this:
PATH_TO_MY_EXTERNAL_PROGRAM = r"C:\ProgramFiles\MyProgram\MyProgramLauncher.exe"
subprocess.call([PATH_TO_MY_EXTERNAL_PROGRAM])
If it is as simple as calling an exe though, you could just use:
PATH_TO_MY_EXTERNAL_PROGRAM = r"C:\ProgramFiles\MyProgram\MyProgramLauncher.exe"
os.system(PATH_TO_MY_EXTERNAL_PROGRAM)
Hope this helps.
-Alex