Extract instance related logical units from cmdlib

All LUInstance* classes are extracted to instance.py. Common functions
are moved to common.py if used by non-instance logical units as well.
Additionally, helper functions which are only used by LUBackup* and
LUInstance* are moved to instance_utils.py.
Signed-off-by: Thomas Thrainer <thomasth@google.com>
Reviewed-by: Bernardo Dal Seno <bdalseno@google.com>

Makefile.am

@@ -314,6 +314,8 @@ cmdlib_PYTHON = \
 	lib/cmdlib/cluster.py \
 	lib/cmdlib/group.py \
 	lib/cmdlib/node.py \
+	lib/cmdlib/instance.py \
+	lib/cmdlib/instance_utils.py \
 	lib/cmdlib/tags.py \
 	lib/cmdlib/network.py \
 	lib/cmdlib/test.py

lib/cmdlib/common.py

@@ -1002,8 +1002,9 @@ def _FindFaultyInstanceDisks(cfg, rpc_runner, instance, node_name, prereq):
   for dev in instance.disks:
     cfg.SetDiskID(dev, node_name)
 
-  result = rpc_runner.call_blockdev_getmirrorstatus(node_name, (instance.disks,
-                                                                instance))
+  result = rpc_runner.call_blockdev_getmirrorstatus(node_name,
+                                                    (instance.disks,
+                                                     instance))
   result.Raise("Failed to get disk status from node %s" % node_name,
                prereq=prereq, ecode=errors.ECODE_ENVIRON)
 
@@ -1012,3 +1013,18 @@ def _FindFaultyInstanceDisks(cfg, rpc_runner, instance, node_name, prereq):
       faulty.append(idx)
 
   return faulty
+
+
+def _CheckNodeOnline(lu, node, msg=None):
+  """Ensure that a given node is online.
+
+  @param lu: the LU on behalf of which we make the check
+  @param node: the node to check
+  @param msg: if passed, should be a message to replace the default one
+  @raise errors.OpPrereqError: if the node is offline
+
+  """
+  if msg is None:
+    msg = "Can't use offline node"
+  if lu.cfg.GetNodeInfo(node).offline:
+    raise errors.OpPrereqError("%s: %s" % (msg, node), errors.ECODE_STATE)

test/py/ganeti.config_unittest.py

@@ -24,12 +24,8 @@
 
 import unittest
 import os
-import time
 import tempfile
-import os.path
-import socket
 import operator
-import itertools
 
 from ganeti import bootstrap
 from ganeti import config
@@ -39,7 +35,7 @@ from ganeti import objects
 from ganeti import utils
 from ganeti import netutils
 from ganeti import compat
-from ganeti import cmdlib
+from ganeti.cmdlib import instance
 
 from ganeti.config import TemporaryReservationManager
 
@@ -614,7 +610,7 @@ class TestCheckInstanceDiskIvNames(unittest.TestCase):
   def testNoError(self):
     disks = self._MakeDisks(["disk/0", "disk/1"])
     self.assertEqual(config._CheckInstanceDiskIvNames(disks), [])
-    cmdlib._UpdateIvNames(0, disks)
+    instance._UpdateIvNames(0, disks)
     self.assertEqual(config._CheckInstanceDiskIvNames(disks), [])
 
   def testWrongNames(self):
@@ -625,7 +621,7 @@ class TestCheckInstanceDiskIvNames(unittest.TestCase):
       ])
 
     # Fix names
-    cmdlib._UpdateIvNames(0, disks)
+    instance._UpdateIvNames(0, disks)
     self.assertEqual(config._CheckInstanceDiskIvNames(disks), [])