Change in vdsm[master]: guestagent: Simpler and safer disk mapping hash

Wednesday, 29 October 2014

Nir Soffer has uploaded a new change for review.

Change subject: guestagent: Simpler and safer disk mapping hash
......................................................................

guestagent: Simpler and safer disk mapping hash

Previously diskMapingHash was initialized to the magic value 0, or to
hash of a sorted json dump of the diskMapping dict. Now diskMappingHash
is always a real hash, and is read only.

The hash is computed automatically when the value of guestDiskMapping is
changed, and there is no way to forget to update the hash.

Change-Id: Ia914cf9860cef019b3040a3f034e479e6a93ed97
Signed-off-by: Nir Soffer <nsoffer(a)redhat.com&gt;
---
M tests/guestagentTests.py
M vdsm/virt/guestagent.py
2 files changed, 28 insertions(+), 3 deletions(-)


  git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/25/34625/1

diff --git a/tests/guestagentTests.py b/tests/guestagentTests.py
index f4f1a35..d9684ae 100644
--- a/tests/guestagentTests.py
+++ b/tests/guestagentTests.py
@@ -193,3 +193,18 @@
                     # If the message size was within the allowed range
                     # the message should have been put into the guestInfo dict
                     self.assertEqual(self.fakeGuestAgent.guestInfo[k], v)
+
+
+class DiskMappingTests(TestCaseBase):
+
+    def setUp(self):
+        self.agent = guestagent.GuestAgent(None, None, None)
+
+    def test_init(self):
+        self.assertEqual(self.agent.guestDiskMapping, {})
+        self.assertTrue(isinstance(self.agent.diskMappingHash, int))
+
+    def test_change_disk_mapping(self):
+        old_hash = self.agent.diskMappingHash
+        self.agent.guestDiskMapping = {'/dev/vda': 'xxx'}
+        self.assertNotEqual(self.agent.diskMappingHash, old_hash)
diff --git a/vdsm/virt/guestagent.py b/vdsm/virt/guestagent.py
index a403b0d..dbada69 100644
--- a/vdsm/virt/guestagent.py
+++ b/vdsm/virt/guestagent.py
@@ -121,7 +121,6 @@
         self._stopped = True
         self.guestStatus = None
         self.guestDiskMapping = {}
-        self.diskMappingHash = 0
         self.guestInfo = {
             'username': user,
             'memUsage': 0,
@@ -136,6 +135,19 @@
         self._agentTimestamp = 0
         self._channelListener = channelListener
         self._messageState = MessageState.NORMAL
+
+    @property
+    def guestDiskMapping(self):
+        return self._guestDiskMapping
+
+    @guestDiskMapping.setter
+    def guestDiskMapping(self, value):
+        self._guestDiskMapping = value
+        self._diskMappingHash = hash(json.dumps(value, sort_keys=True))
+
+    @property
+    def diskMappingHash(self):
+        return self._diskMappingHash
 
     def connect(self):
         self._prepare_socket()
@@ -303,8 +315,6 @@
                 disks.append(disk)
             self.guestInfo['disksUsage'] = disks
             self.guestDiskMapping = args.get('mapping', {})
-            self.diskMappingHash = hash(json.dumps(self.guestDiskMapping,
-                                                   sort_keys=True))
         elif message == 'number-of-cpus':
             self.guestInfo['guestCPUCount'] = int(args['count'])
         else:


-- 
To view, visit http://gerrit.ovirt.org/34625
To unsubscribe, visit http://gerrit.ovirt.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: Ia914cf9860cef019b3040a3f034e479e6a93ed97
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Nir Soffer <nsoffer(a)redhat.com&gt;

    

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