Step 1: Tells us which model PI, which OS, which named release of that OS you are using and whether it is booting to desktop or command line. And with or without automatic login. If booting to the desktop, X11, wayfire, or labwc?
Step 2: share the actual error messages you're getting.
Step 3: share your .service file and, maybe, your code.
Some further tips/pointers/questions:
As for which dependencies you add to your service, there is no correct answer. But remember services can disappear behind your program's back and systemd does not (indeed cannot) notify your program of this.
Step 2: share the actual error messages you're getting.
Step 3: share your .service file and, maybe, your code.
My difficulty is that the program seems to break when called by the service. It seems as though the program is run in the background and in a different means than when called directly from the command line, and program B becomes unable to reach its dependencies. Has anyone had similar problems? Are there any easy ways around this? Can I get the .service to call the function more like a basic command line prompt would? Are there better means than service files to run programs automatically at start up? Regarding the dependencies for program B, should I be importing them in the .service file or in program A in order to get them to load correctly?
Some further tips/pointers/questions:
- Yes, systemd services run in the background. By default any print statements and errors output to the systemd journal.
- By default systemd services run as root
- By default, the PWD for a service is the running user's home directory (e.g. /root). This may not be what your code expects.
- Any python venv will not be activated
- Much of the environment will be different to what you and your code expects.
- A logged in desktop may not be available when your program starts.
- Services such as networking may not be available when your program starts.
- Systemd will not automatically restart failed sub programs.
- If this were my project and if the sub programs being called were also written by me I'd:
- Make sure all of them have appropriate exception handling so they don't just crash.
- Identify the dependencies for each one and the common dependencies.
- Write each sub program so that it can be imported as a module and called as a function from the main program rather than using subprocess.
(it's not that hard. Here's a noddy example:Save as helloworld.py then use as you would any other python module.)Code:
def run(): print('hello world!')If __name__ == '__main__': run() - If multiple sub programs must be run concurrently use threads.
As for which dependencies you add to your service, there is no correct answer. But remember services can disappear behind your program's back and systemd does not (indeed cannot) notify your program of this.
Statistics: Posted by thagrol — Sat Nov 09, 2024 6:05 pm