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author | John Snow <jsnow@redhat.com> | 2022-01-31 23:11:32 -0500 |
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committer | John Snow <jsnow@redhat.com> | 2022-02-02 14:12:22 -0500 |
commit | 50465f94d211beabfbfc80e4f85ec4fad0757570 (patch) | |
tree | bf8655489b2aa82dc78a029a44b0d6e534c1db73 /python/qemu | |
parent | fa73e6e4ca1a93c5bbf9d05fb2a25736ab810b35 (diff) | |
download | qemu-50465f94d211beabfbfc80e4f85ec4fad0757570.zip qemu-50465f94d211beabfbfc80e4f85ec4fad0757570.tar.gz qemu-50465f94d211beabfbfc80e4f85ec4fad0757570.tar.bz2 |
python/machine: raise VMLaunchFailure exception from launch()
This allows us to pack in some extra information about the failure,
which guarantees that if the caller did not *intentionally* cause a
failure (by capturing this Exception), some pretty good clues will be
printed at the bottom of the traceback information.
This will help make failures in the event of a non-negative return code
more obvious when they go unhandled; the current behavior in
_post_shutdown() is to print a warning message only in the event of
signal-based terminations (for negative return codes).
(Note: In Python, catching BaseException instead of Exception catches a
broader array of Exception events, including SystemExit and
KeyboardInterrupt. We do not want to "wrap" such exceptions as a
VMLaunchFailure, because that will 'downgrade' the exception from a
BaseException to a regular Exception. We do, however, want to perform
cleanup in either case, so catch on the broadest scope and
wrap-and-re-raise only in the more targeted scope.)
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20220201041134.1237016-3-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
Diffstat (limited to 'python/qemu')
-rw-r--r-- | python/qemu/machine/machine.py | 45 |
1 files changed, 39 insertions, 6 deletions
diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py index 67ab06c..a5972fa 100644 --- a/python/qemu/machine/machine.py +++ b/python/qemu/machine/machine.py @@ -74,6 +74,35 @@ class QEMUMachineAddDeviceError(QEMUMachineError): """ +class VMLaunchFailure(QEMUMachineError): + """ + Exception raised when a VM launch was attempted, but failed. + """ + def __init__(self, exitcode: Optional[int], + command: str, output: Optional[str]): + super().__init__(exitcode, command, output) + self.exitcode = exitcode + self.command = command + self.output = output + + def __str__(self) -> str: + ret = '' + if self.__cause__ is not None: + name = type(self.__cause__).__name__ + reason = str(self.__cause__) + if reason: + ret += f"{name}: {reason}" + else: + ret += f"{name}" + ret += '\n' + + if self.exitcode is not None: + ret += f"\tExit code: {self.exitcode}\n" + ret += f"\tCommand: {self.command}\n" + ret += f"\tOutput: {self.output}\n" + return ret + + class AbnormalShutdown(QEMUMachineError): """ Exception raised when a graceful shutdown was requested, but not performed. @@ -397,7 +426,7 @@ class QEMUMachine: try: self._launch() - except: + except BaseException as exc: # We may have launched the process but it may # have exited before we could connect via QMP. # Assume the VM didn't launch or is exiting. @@ -408,11 +437,15 @@ class QEMUMachine: else: self._post_shutdown() - LOG.debug('Error launching VM') - if self._qemu_full_args: - LOG.debug('Command: %r', ' '.join(self._qemu_full_args)) - if self._iolog: - LOG.debug('Output: %r', self._iolog) + if isinstance(exc, Exception): + raise VMLaunchFailure( + exitcode=self.exitcode(), + command=' '.join(self._qemu_full_args), + output=self._iolog + ) from exc + + # Don't wrap 'BaseException'; doing so would downgrade + # that exception. However, we still want to clean up. raise def _launch(self) -> None: |