I'm still new to writing scripts with Python and would really appreciate some guidance.
I'm wondering how to continue executing my Python script from where it left off after a system restart.
The script essentially alternates between restarting and executing a task for example: restart the system, open an application and execute a task, restart the system, open another application and execute another task, etc...
But the issue is that once the system restarts and logs back in, all applications shut down including the terminal so the script stops running and never executes the following task. The program shuts down early without an error so the logs are not really of much use. Is there any way to reopen the script and continue from where it left off or prevent applications from being closed during a reboot ? Any guidance on the issue would be appreciated.
Thanks!
Also, I'm using a Mac running High Sierra for reference.
You could write your current progress to a file just before you reboot and read said file on Programm start.
About the automatic restart of the script after reboot: you could have the script to put itself in the Autostart of your system and after everything is done remove itself from it.
Related
I'm trying to achieve something ; I created a exe file, that automatically force shutdown the computer at 11 pm.
I would like to make this script impossible to stop or crash, or even make the entire system crash if the program is closed.
How can i achieve this ?
Note :
I'm on a laptop, running windows 10. I made a python file, and i converted it in an exe file with py installer. Then i created a shortcut to that exe file that run the program with admin rights
If you mark the process as critical Windows will trigger a blue screen crash if that process is stopped/killed.
There is information about how to do this here
Note: Although it is possible to do this, it is not a good idea to do so. For example as suggested by Anders, use a Scheduled Task. Having the system crash could result in information loss, or other unintended consequences.
Create a Windows service. You can deny Administrators trying to stop/pause the service, that should slow them down a little bit.
Or since we are talking about triggering something at a specific time, you might want to use the task scheduler instead.
In any case, you will never fully lock down something like this from an Administrator since they can always take ownership and modify the ACL.
I have a python program which is instantier as a linux service.
This service updates itself by downloading a new version of the code on an ftp server and launches a bash file to update the service.
In this file I have a line that destroys the current service before recreating it with the new source code.
I run this bash script with:
subprocess.call("sudo bash /home/pi/install.sh",shell=True)
I understand that this "subprocess" lives in my python program. And the bash script stop the linux service so stop the python program so stop itself ... And so it never ends.
What are the solutions to solve my problem?
I think there's several ways to do it - one of them being (maybe not the most elegant?) to make your python schedule a cron-job of the bash-script using python-crontab.
Say it's 13:00 and you want your job to run - then make the python script schedule a cron-job to 13:05 (just to add a time buffer).
You can then remove your cron-job after the bash-job has been run, either manually or implement it in your bash-script (or make it call a python script which uses python-crontab to remove it, it's fairly easy to do so)
Don't let the script stop the service. Just let it exit with a specific exit code if it installed a new version, and restart the service accordingly in the Python code.
Unfortunately, I can't seem to use Windows Task Scheduler as I don't have admin rights on my work computer, and when I sign in as admin to run tasks the Python script doesn't run. Because of this, the only alternative I've found is creating a bash script that will run my .py file and adding that to my programs that run on startup.
This seems to work fine whenever I restart my computer, but I notice that if I leave my computer on overnight the batch script will close and my Python script won't run. I've checked the log files for any errors and there don't seem to be any issues in the script, it just seems that the cmd prompt screen closes.
Here is what I put in my .bat file:
"C:\Python\Python37-32\python.exe" "T:\service.py" > T:\output.log 2>&1
cmd /k
Just trying to figure out- why is this happening? And is there any way I can just keep this script running as long as my computer is on?
You could attempt to create a Windows Service with PowerShell. Just have it automatically recover when it's terminated. See this as a reference.
https://github.com/yaplex/CodeSamples/blob/092159a847e330778494ea7b69ee84d120db7e36/PowerShell/Install-Windows-Service.ps1
Then you can monitor trends with Event Viewer as to why and when it's terminated.
What is the correct way to have python schedule (by daniel bader) persistently run. I currently run the job by having a terminal open, connected to a VM where the scripts actually run. There I run python "scheduler.py" - where scheduler.py has all the jobs.
But when the connection closes, or I close the terminal, the scheduler stops.
Any easy solutions to fix this?
You have a couple options here. You are starting the process in your ssh session, but then killing the ssh session, which then kills the process.
One way to handle this, would be to have the VM run the script on startup. You could set the script as a service, so even if it goes down for some reason it will come back up. Read into init.rc for info on how launch a script at boot on linux. I'm not well-versed in Windows any more but I believe there is a way to do the same.
Another option is to keep the session open by connecting to it with screen or tmux. This article explains the problem some and gives you a few different ways to work around the issue: https://www.tecmint.com/keep-remote-ssh-sessions-running-after-disconnection/
I am using Debian and I have a python script that I would like to run during rc.local so that it will run on boot. I already have it working with a test file that is meant to run and terminate.
The problem is that this file should eventually run indefinitely using Scheduler. It's job is to do serial reads, a small amount of processing on those reads, and inserts into a MySQL database. However, I am nervous about then not being able to cancel the script to get to my login prompt if changes need to be made since I was unable to terminate the test script early using Ctrl+C (^C).
My hope is that there is some command that I am just missing that will accomplish this. Is there another key command that I'm missing that will terminate the python script and end rc.local?
Thanks.
EDIT: Another possible solution that would help me here is if there is a way to start a python script in the background during boot. So it would start the script and then allow login while continuing to run the script in the background.
I'm starting to think this isn't something that's possible to accomplish so other suggestions to accomplish something similar to what I'm trying to do would be helpful as well.
Thanks again.
Seems like it was just a dumb mistake on my part.
I realized the whole point of this was to allow the python script to run as a background process during boot so I added the " &" to the end of the script call like you would when running it from the shell and viola I can get to my password prompt by pressing "Enter".
I wanted to put this answer here just in case this would be something horribly wrong to do, but it accomplishes what I was looking for.
Making scripts run at boot time with Debian
Put your script in /etc/init.d/. So, if your script is in a file called my_script, it should be located at /etc/init.d/my_script.
Run update-rc.d my_script defaults as root.
Don't forget to make your script executable and include the shebang. That means the first line of the script should be #!/usr/bin/python.