[v6,05/10] qemu.py: Use custom exceptions rather than Exception

Commit Message

Lukáš Doktor Aug. 18, 2017, 2:26 p.m. UTC

The naked Exception should not be widely used. It makes sense to be a
bit more specific and use better-suited custom exceptions. As a benefit
we can store the full reply in the exception in case someone needs it
when catching the exception.

Signed-off-by: Lukáš Doktor <[e-mail]>
Reviewed-by: Eduardo Habkost <[e-mail]>
---
 scripts/qemu.py | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

Patch

diff --git a/scripts/qemu.py b/scripts/qemu.py
index 19cbd34..97ecb63 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -19,6 +19,19 @@  import subprocess
 import qmp.qmp
 
 
+class MonitorResponseError(qmp.qmp.QMPError):
+    '''
+    Represents erroneous QMP monitor reply
+    '''
+    def __init__(self, reply):
+        try:
+            desc = reply["error"]["desc"]
+        except KeyError:
+            desc = reply
+        super(MonitorResponseError, self).__init__(desc)
+        self.reply = reply
+
+
 class QEMUMachine(object):
     '''A QEMU VM'''
 
@@ -199,9 +212,9 @@  class QEMUMachine(object):
         '''
         reply = self.qmp(cmd, conv_keys, **args)
         if reply is None:
-            raise Exception("Monitor is closed")
+            raise qmp.qmp.QMPError("Monitor is closed")
         if "error" in reply:
-            raise Exception(reply["error"]["desc"])
+            raise MonitorResponseError(reply)
         return reply["return"]
 
     def get_qmp_event(self, wait=False):