I have python script that runs on a windows machine and when the machine receives updates and shuts down for a reboot I would like to listen for that signal and gracefully handle cleanup in my script.
When a process is killed via normal means my understanding is that the process is sent the SIGTERMsignal. This signal can be caught and processed.
However it seems that when the system performs an automatic reboot due to windows updates there may not be a SIGTERM signal sent? Is SIGKILL sent instead? I understand that SIGKILL cannot be caught and the process is pretty much dead, this I can live with - it just changes my strategy on how I will recover.
I understand the process by which I can listen for signals in Python, what I am specifically asking for is clarification on what signal is sent to a process when windows automatically reboots after a windows update
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I'm developing a python script that runs as a daemon in a linux environment. If and when I need to issue a shutdown/restart operation to the device, I want to do some cleanup and log data to a file to persist it through the shutdown.
I've looked around regarding Linux shutdown and I can't find anything detailing which, if any, signal, is sent to applications at the time of shutdown/restart. I assumed sigterm but my tests (which are not very good tests) seem to disagree with this.
When Linux is shutting down, (and this is slightly dependent on what kind of init scripts you are using) it first sends SIGTERM to all processes to shut them down, and then I believe will try SIGKILL to force them to close if they're not responding to SIGTERM.
Please note, however, that your script may not receive the SIGTERM - init may send this signal to the shell it's running in instead and it could kill python without actually passing the signal on to your script.
Hope this helps!
I'm trying to launch a background process (a Python daemon to be exact) on my iPod (ios 6.1.6 jailbroken), but the Python process gets suspended eventually by the os.
Here are the things I tried to make it run in background:
Launch the process via MobileTerminal. It gets suspended when I hit the home button, same when installing MobileTerminal Backgrounder or configuring the MobileTerminal app to run in background mode with Background Manager.
SSH connect and launch the process with nohup, it also gets suspended. Setting the highest priority with nice also does not work.
Does anyone have some ideas how to achieve this? This must be possible, because processes like the openssh server seem to have permanent background.
I looked on the internet for quite a while, and the only helpful thing I found that might work is to set up a launch daemon, but this makes it not easy to stop / restart the process if I have to restart the device, and I do not know if it works for sure.
Thanks.
Using parallel python 1.6.4 I spawn a subprocess.Popen command on a remote server. For whatever reason, the command isn't completing in a timely matter, i.e., within the socket_timeout I've set. In this case, I expected parallel python to fail, kill the remote process, and maybe raise an exception. Instead, the long process keeps running, and the ppserver quietly spawns another one!
How can I configure ppserver to fail?
Short of that, I suppose I have to set timer, and destroy the job_server to make it close out and clean up the bad process?
Hi is there a way out to gracefully shutdown the bottle server. In a way it should be able to do few steps before it eventually stops. This is critical for some clean up of threads and db state etc avoiding the corrupt state during the restart.
I am using mod wsgi apache module for running the bottle server.
In mod_wsgi you can register atexit callbacks and they will be called on normal process shutdown. You don't have too long to do stuff though. If embedded mode, or daemon mode and shutdown caused by Apache restart, you have only 3 seconds as Apache will kill off processes forcibly after that. If daemon mode and trigger is due to touching WSGI script file or you explicitly sent daemon process a signal, you have 5 seconds, which is when mod_wsgi will decide it is taking too long and forcibly kill them.
See the 'atexit' module in Python.
I've got a Python script managing a gdb process on Windows, and I need to be able to send a SIGINT to the spawned process in order to halt the target process (managed by gdb)
It appears that there is only SIGTERM available in Win32, but clearly if I run gdb from the console and Ctrl+C, it thinks it's receiving a SIGINT. Is there a way I can fake this such that the functionality is available on all platforms?
(I am using the subprocess module, and python 2.5/2.6)
Windows doesn't have the unix signals IPC mechanism.
I would look at sending a CTRL-C to the gdb process.