[Qemu-devel] [PATCH v7 11/11] qemu.py: refactor launch()

[Amador Pahim <apahim@redhat.com>]

This is just an refactor to separate the exception handler from the
actual launch procedure, improving the readability and making future
maintenances in this piece of code easier.

Signed-off-by: Amador Pahim <apahim@redhat.com>
---
 scripts/qemu.py | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/scripts/qemu.py b/scripts/qemu.py
index 2bd81afcf2..7f890ff8e5 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -167,10 +167,10 @@ class QEMUMachine(object):
             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')
+        '''
+        Try to launch the VM and make sure we cleanup and expose the
+        command line/output in case of exception.
+        '''
         if self.is_running():
             raise QEMULaunchError('VM already running')
 
@@ -178,15 +178,7 @@ class QEMUMachine(object):
             raise QEMULaunchError('Shutdown pending after previous launch')
 
         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=self._qemu_log_fd,
-                                           stderr=subprocess.STDOUT,
-                                           shell=False)
-            self._post_launch()
+            self._launch()
             self._pending_shutdown = True
         except:
             self.shutdown()
@@ -199,6 +191,21 @@ class QEMUMachine(object):
 
             raise
 
+    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')
+        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=self._qemu_log_fd,
+                                       stderr=subprocess.STDOUT,
+                                       shell=False)
+        self._post_launch()
+
     def shutdown(self):
         '''Terminate the VM and clean up'''
         if self.is_running():
-- 
2.13.5