pycriu: better socket error handling

[herheliuk]

[Errno 2] No such file or directory -> Socket file not found.
[Errno 111] Connection refused -> Service not running.

Signed-off-by: Andrii Herheliuk [email protected]

[Copilot]

Pull Request Overview

This PR improves error handling for socket connection failures in the CRIU Python library by catching and re-raising specific socket exceptions with more user-friendly error messages.

Key Changes:

• Added try-except block around socket connection logic
• Added FileNotFoundError handling for missing socket files
• Added ConnectionRefusedError handling for service unavailability

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[herheliuk]

@avagin do you want me to change that?

pycriu.criu.CRIUExceptionInternal: DUMP failed with internal error: Service not running.

I think it's a bit too long already (in a traceback)

pycriu.criu.CRIUExceptionInternal: DUMP failed with internal error: Service not running: criu_service.socket

And people can easily handle that themselves with try/except if they want to.

[herheliuk]

Copilot said: The error message loses the original socket path information.

There is no path information there, and the original error is still in the stack trace.

Traceback (most recent call last):
  File "/home/user/criu_api/env/lib/python3.12/site-packages/pycriu/criu.py", line 49, in connect
    self.sk.connect(self.comm)
FileNotFoundError: [Errno 2] No such file or directory

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/user/criu_api/env/lib/python3.12/site-packages/pycriu/criu.py", line 252, in _send_req_and_recv_resp
    s = self._comm.connect(daemon)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/criu_api/env/lib/python3.12/site-packages/pycriu/criu.py", line 52, in connect
    raise FileNotFoundError("Socket file not found.")
FileNotFoundError: Socket file not found.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/user/criu_api/test.py", line 16, in <module>
    criu.dump()
  File "/home/user/criu_api/env/lib/python3.12/site-packages/pycriu/criu.py", line 293, in dump
    resp = self._send_req_and_recv_resp(req)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/user/criu_api/env/lib/python3.12/site-packages/pycriu/criu.py", line 269, in _send_req_and_recv_resp
    raise CRIUExceptionInternal(req.type, str(e))
pycriu.criu.CRIUExceptionInternal: DUMP failed with internal error: Socket file not found.