| Message ID | 20191227134101.244496-5-wainersm@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | python/qemu: qmp: Fix, delint and improvements | expand |
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 <wainersm@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? close() I suspect might need to actually unset the __sock and __sockfile fields. > > def settimeout(self, timeout): > """ >
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 <wainersm@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): >> """ >>
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() def settimeout(self, timeout): """
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 <wainersm@redhat.com> --- python/qemu/qmp.py | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)