iallocator: computation of storage data

This patch extracts the processing of the storage-related
data from the RPC call 'node_info' in a separate function
to increase testability. In addition, this patch contains
unit tests for this function.
Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

lib/masterd/iallocator.py

@@ -543,6 +543,37 @@ class IAllocator(object):
                                (node_name, attr, value))
     return value
 
+  @staticmethod
+  def _ComputeStorageData(node_info, node_name, has_lvm):
+    """Extract storage data from the node info.
+
+    @type node_info: see result of RPC call 'node info'
+    @param node_info: the node's live information
+    @type node_name: string
+    @param node_name: the node's name
+    @type has_lvm: boolean
+    @param has_lvm: whether or not lvm storage info was requested
+    @rtype: 4-tuple of integers
+    @return: tuple of storage info (total_disk, free_disk, total_spindles,
+       free_spindles)
+
+    """
+    # TODO: replace this with proper storage reporting
+    if has_lvm:
+      total_disk = IAllocator._GetAttributeFromNodeData(node_info, node_name,
+                                                        "storage_size")
+      free_disk = IAllocator._GetAttributeFromNodeData(node_info, node_name,
+                                                       "storage_free")
+      total_spindles = IAllocator._GetAttributeFromNodeData(
+          node_info, node_name, "spindles_total")
+      free_spindles = IAllocator._GetAttributeFromNodeData(
+          node_info, node_name, "spindles_free")
+    else:
+      # we didn't even ask the node for VG status, so use zeros
+      total_disk = free_disk = 0
+      total_spindles = free_spindles = 0
+    return (total_disk, free_disk, total_spindles, free_spindles)
+
   def _ComputeDynamicNodeData(self, node_cfg, node_data, node_iinfo, i_list,
                               node_results, has_lvm):
     """Compute global node data.
@@ -583,20 +614,8 @@ class IAllocator(object):
             if iinfo.admin_state == constants.ADMINST_UP:
               i_p_up_mem += beinfo[constants.BE_MAXMEM]
 
-        # TODO: replace this with proper storage reporting
-        if has_lvm:
-          total_disk = self._GetAttributeFromNodeData(remote_info, ninfo.name,
-                                                      "storage_size")
-          free_disk = self._GetAttributeFromNodeData(remote_info, ninfo.name,
-                                                     "storage_free")
-          total_spindles = self._GetAttributeFromNodeData(
-              remote_info, ninfo.name, "spindles_total")
-          free_spindles = self._GetAttributeFromNodeData(
-              remote_info, ninfo.name, "spindles_free")
-        else:
-          # we didn't even ask the node for VG status, so use zeros
-          total_disk = free_disk = 0
-          total_spindles = free_spindles = 0
+        (total_disk, free_disk, total_spindles, free_spindles) = \
+            self._ComputeStorageData(remote_info, ninfo.name, has_lvm)
 
         # compute memory used by instances
         pnr_dyn = {

test/py/ganeti.masterd.iallocator_unittest.py

@@ -22,12 +22,14 @@
 """Script for testing ganeti.masterd.iallocator"""
 
 import unittest
+import mock
 
 from ganeti import compat
 from ganeti import constants
 from ganeti import errors
 from ganeti import objects
 from ganeti import ht
+from ganeti import rpc
 from ganeti.masterd import iallocator
 
 import testutils
@@ -177,6 +179,49 @@ class TestComputeBasicNodeData(unittest.TestCase):
       else:
         self.assertTrue(result["node1"]["offline"])
 
+class TestProcessStorageInfo(unittest.TestCase):
+
+  def setUp(self):
+    self.free_storage_file = 23
+    self.total_storage_file = 42
+    self.free_storage_lvm = 69
+    self.total_storage_lvm = 666
+    self.space_info = [{"name": "mynode",
+                       "type": constants.ST_FILE,
+                       "storage_free": self.free_storage_file,
+                       "storage_size": self.total_storage_file},
+                      {"name": "mynode",
+                       "type": constants.ST_LVM_VG,
+                       "storage_free": self.free_storage_lvm,
+                       "storage_size": self.total_storage_lvm},
+                      {"name": "mynode",
+                       "type": constants.ST_LVM_PV,
+                       "storage_free": 33,
+                       "storage_size": 44}]
+    self.node_info = ("123", self.space_info, ({},))
+
+  def testComputeStorageDataLvm(self):
+    has_lvm = True
+    node_name = "mynode"
+    remote_info = rpc.MakeLegacyNodeInfo(self.node_info,
+                                         require_vg_info=has_lvm)
+    (total_disk, free_disk, total_spindles, free_spindles) = \
+      iallocator.IAllocator._ComputeStorageData(remote_info, node_name, has_lvm)
+    self.assertEqual(self.free_storage_lvm, free_disk)
+    self.assertEqual(self.total_storage_lvm, total_disk)
+
+  def testComputeStorageDataDefault(self):
+    has_lvm = False
+    node_name = "mynode"
+    remote_info = rpc.MakeLegacyNodeInfo(self.node_info,
+                                         require_vg_info=has_lvm)
+    (total_disk, free_disk, total_spindles, free_spindles) = \
+      iallocator.IAllocator._ComputeStorageData(remote_info, node_name, has_lvm)
+    # FIXME: right now, iallocator ignores anything else than LVM, adjust
+    # this test once that arbitrary storage is supported
+    self.assertEqual(0, free_disk)
+    self.assertEqual(0, total_disk)
+
 
 if __name__ == "__main__":
   testutils.GanetiTestProgram()