On Thu, Sep 14, 2017 at 09:38:13PM +0200, Amador Pahim wrote: > On Tue, Sep 5, 2017 at 5:18 AM, Fam Zheng <f...@redhat.com> wrote: > > On Fri, 09/01 13:28, Amador Pahim wrote: > >> To launch a VM, we need to create basically two files: the monitor > >> socket (if it's a UNIX socket) and the qemu log file. > >> > >> For the qemu log file, we currently just open the path, which will > >> create the file if it does not exist or overwrite the file if it does > >> exist. > >> > >> For the monitor socket, if it already exists, we are currently removing > >> it, even if it's not created by us. > >> > >> This patch moves to pre_launch() the responsibility to make sure we only > >> create files that are not pre-existent and to populate a list of > >> controlled files. This list will then be used as the reference of > >> files to remove during the cleanup (post_shutdown()). > >> > >> Signed-off-by: Amador Pahim <apa...@redhat.com> > >> --- > >> scripts/qemu.py | 30 +++++++++++++++++++++++------- > >> 1 file changed, 23 insertions(+), 7 deletions(-) > >> > >> diff --git a/scripts/qemu.py b/scripts/qemu.py > >> index 3ebe5ee0a4..c26e1412f9 100644 > >> --- a/scripts/qemu.py > >> +++ b/scripts/qemu.py > >> @@ -41,6 +41,7 @@ class QEMUMachine(object): > >> monitor_address = os.path.join(test_dir, name + > >> "-monitor.sock") > >> self._monitor_address = monitor_address > >> self._qemu_log_path = os.path.join(test_dir, name + ".log") > >> + self._qemu_log_fd = None > >> self._popen = None > >> self._binary = binary > >> self._args = list(args) # Force copy args in case we modify them > >> @@ -50,6 +51,7 @@ class QEMUMachine(object): > >> self._socket_scm_helper = socket_scm_helper > >> self._debug = debug > >> self._qemu_full_args = None > >> + self._created_files = [] > >> > >> # This can be used to add an unused monitor instance. > >> def add_monitor_telnet(self, ip, port): > >> @@ -128,30 +130,44 @@ class QEMUMachine(object): > >> '-display', 'none', '-vga', 'none'] > >> > >> def _pre_launch(self): > >> - self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address, > >> server=True, > >> - debug=self._debug) > >> + try: > >> + self._qmp = qmp.qmp.QEMUMonitorProtocol(self._monitor_address, > >> + server=True, > >> + debug=self._debug) > >> + except: > >> + raise > > > > What's the point of "except: raise"? It seems useless. > > The point is to execute the block in the else only when no exception > happens. When some exception happens, I want to raise it without > executing the else block.
Isn't this exactly what Python does when an exception is raised with no "try" block? > > > > >> + else: > >> + if not isinstance(self._monitor_address, tuple): > >> + self._created_files.append(self._monitor_address) > >> + > >> + try: > >> + flags = os.O_CREAT | os.O_EXCL | os.O_WRONLY > >> + os.open(self._qemu_log_path, flags) > > > > Why change to os.open() instead of open()? > > I want to create the file only if it does not exist. The open() flag > 'x' is available only in python 3.3. For python <3.3, we need the > os.open() to have that feature. I'm not sure this extra complexity is really necessary. We could fix all that by using mkdtemp() and deleting the temporary directory on shutdown. > > > > >> + except: > >> + raise > >> + else: > >> + self._created_files.append(self._qemu_log_path) > >> + self._qemu_log_fd = open(self._qemu_log_path, 'wb') > >> > >> def _post_launch(self): > >> self._qmp.accept() > >> > >> def _post_shutdown(self): > >> - if not isinstance(self._monitor_address, tuple): > >> - self._remove_if_exists(self._monitor_address) > >> - self._remove_if_exists(self._qemu_log_path) > >> + while self._created_files: > >> + self._remove_if_exists(self._created_files.pop()) > >> > >> def launch(self): > >> '''Launch the VM and establish a QMP connection''' > >> self._iolog = None > >> self._qemu_full_args = None > >> devnull = open(os.path.devnull, 'rb') > >> - qemulog = open(self._qemu_log_path, 'wb') > >> try: > >> self._pre_launch() > >> self._qemu_full_args = (self._wrapper + [self._binary] + > >> self._base_args() + self._args) > >> self._popen = subprocess.Popen(self._qemu_full_args, > >> stdin=devnull, > >> - stdout=qemulog, > >> + stdout=self._qemu_log_fd, > >> stderr=subprocess.STDOUT, > >> shell=False) > >> self._post_launch() > >> -- > >> 2.13.5 > >> > > > > Fam -- Eduardo