On 1/8/20 10:23 PM, John Snow wrote:
On 12/27/19 8:41 AM, Wainer dos Santos Moschetta wrote:This implement the __enter__ and __exit__ functions on QEMUMonitorProtocol class so that it can be used on 'with' statement and the resources will be free up on block end: with QEMUMonitorProtocol(socket_path) as qmp: qmp.connect() qmp.command('query-status') Signed-off-by: Wainer dos Santos Moschetta <waine...@redhat.com> --- python/qemu/qmp.py | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/python/qemu/qmp.py b/python/qemu/qmp.py index 914b8c6774..6d55f53595 100644 --- a/python/qemu/qmp.py +++ b/python/qemu/qmp.py @@ -139,6 +139,15 @@ class QEMUMonitorProtocol: raise QMPConnectError("Error while reading from socket") self.__sock.settimeout(None)+ def __enter__(self):+ # Implement context manager enter function. + return self + + def __exit__(self, exc_type, exc_value, exc_traceback): + # Implement context manager exit function. + self.close() + return False + def connect(self, negotiate=True): """ Connect to the QMP Monitor and perform capabilities negotiation. @@ -259,8 +268,10 @@ class QEMUMonitorProtocol: """ Close the socket and socket file. """ - self.__sock.close() - self.__sockfile.close() + if self.__sock: + self.__sock.close() + if self.__sockfile: + self.__sockfile.close()Not evident on cold read: does self.close() change self.__sock and self.__sockfile such that they are false-ish?
Because self.__exit__() calls self.close() even when a runtime exception raises, there isn't any guarantee that self.__sockfile and self.__sock were initialized. That's the reason why I added those guards.
close() I suspect might need to actually unset the __sock and __sockfile fields.
The QEMUMonitorProtocol object is designed to be disposed after close() being called. So I don't see any reason to unset those fields. Unless I am missing something here...
Thanks for the comments! - Wainer
def settimeout(self, timeout):"""
