CP-32998 - Use cgclassify to move tapdisk into pre configured vm.slic…

…e and vm-blktap.slice

Signed-off-by: ben.sims@citrix.com <ben.sims@citrix.com>

drivers/blktap2.py

@@ -765,6 +765,22 @@ def launch_from_arg(cls, arg):
         arg = cls.Arg.parse(arg)
         return cls.launch(arg.path, arg.type, False)
 
+    @classmethod
+    def cgclassify(cls, pid):
+
+        # We dont provide any <controllers>:<path>
+        # so cgclassify uses /etc/cgrules.conf which
+        # we have configured in the spec file.
+        cmd = ["cgclassify", str(pid)]
+        try:
+            util.pread2(cmd)
+        except util.CommandException as e:
+            util.logException(e)
+
+    @classmethod
+    def spawn(cls):
+        return TapCtl.spawn()
+
     @classmethod
     def launch_on_tap(cls, blktap, path, _type, options):
 
@@ -775,8 +791,8 @@ def launch_on_tap(cls, blktap, path, _type, options):
         minor = blktap.minor
 
         try:
-            pid = TapCtl.spawn()
-
+            pid = cls.spawn()
+            cls.cgclassify(pid)
             try:
                 TapCtl.attach(pid, minor)
 

tests/test_blktap2.py

@@ -10,6 +10,65 @@
 import testlib
 import util
 
+class BogusException(Exception):
+    pass
+
+class TestTapdisk(unittest.TestCase):
+
+    #
+    # There is a bug in python mocking that prevents @Classmethods being mocked
+    # hence no usual decorator mocks and the monkey patching.
+    # https://bugs.python.org/issue23078
+    #
+
+    @mock.patch('blktap2.util.pread2', autospec=True)
+    def test_cgclassify_normal_call(self, mock_pread2):
+        blktap2.Tapdisk.cgclassify(123)
+        mock_pread2.assert_called_with(['cgclassify', '123'])
+
+    @mock.patch('blktap2.util.pread2', autospec=True)
+    @mock.patch('blktap2.util.logException', autospec=True)
+    def test_cgclassify_exception_swallow(self, mock_log, mock_pread2):
+        mock_pread2.side_effect = util.CommandException(999)
+        blktap2.Tapdisk.cgclassify(123)
+        mock_pread2.assert_called_with(['cgclassify', '123'])
+        self.assertEquals(mock_log.call_count, 1)
+
+    def test_cgclassify_called_by_launch_on_tap(self):
+        blktap = mock.MagicMock()
+        blktap.minor = 2
+
+        # Record old functions
+        spawn_old = blktap2.Tapdisk.spawn
+        cgclassify_old = blktap2.Tapdisk.cgclassify
+        find_by_path_old = blktap2.Tapdisk.find_by_path
+
+        # Begin monkey patching.
+        blktap2.Tapdisk.spawn = mock.MagicMock()
+        blktap2.Tapdisk.spawn.return_value = 123
+
+        # Raise an exception just so we dont have to bother mocking out the
+        # rest of the function.
+        blktap2.Tapdisk.cgclassify = mock.MagicMock()
+        blktap2.Tapdisk.cgclassify.side_effect = BogusException
+
+        blktap2.Tapdisk.find_by_path = mock.MagicMock()
+        blktap2.Tapdisk.find_by_path.return_value = None
+
+        with self.assertRaises(BogusException) as cf:
+            tap = blktap2.Tapdisk.launch_on_tap(blktap,
+                                                "not used",
+                                                "not used",
+                                                "not used")
+
+        blktap2.Tapdisk.cgclassify.assert_called_with(123)
+
+        # Restor old functions.
+        blktap2.Tapdisk.spawn = spawn_old
+        blktap2.Tapdisk.cgclassify = cgclassify_old
+        blktap2.Tapdisk.find_by_path = find_by_path_old
+
+
 class TestVDI(unittest.TestCase):
     # This can't use autospec as vdi is created in __init__
     # See https://docs.python.org/3/library/unittest.mock.html#autospeccing