On Thu, Sep 14, 2017 at 9:46 PM, Eduardo Habkost <ehabk...@redhat.com> wrote: > 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?
Sure, cleaning this up. > > >> >> > >> >> + 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. I thought about that, but I foresee the question: hat happens if between the mkdtemp and the file creation (i.e. self._qemu_log_path) someone goes in that directory and creates a file with the same name of the self._qemu_log_path? Are we going to overwrite it? Ok, very unlikely, but possible. This extra step takes care of that. > >> >> > >> >> + 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
