storage: Use constants.py instead of local constants

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>

lib/constants.py

@@ -187,6 +187,20 @@ ST_FILE = "file"
 ST_LVM_PV = "lvm-pv"
 ST_LVM_VG = "lvm-vg"
 
+# Storage fields
+SF_NAME = "name"
+SF_SIZE = "size"
+SF_FREE = "free"
+SF_USED = "used"
+SF_ALLOCATABLE = "allocatable"
+
+# Available fields per storage type
+VALID_STORAGE_FIELDS = {
+  ST_FILE: frozenset([SF_NAME, SF_USED, SF_FREE]),
+  ST_LVM_PV: frozenset([SF_NAME, SF_SIZE, SF_USED, SF_FREE, SF_ALLOCATABLE]),
+  ST_LVM_VG: frozenset([SF_NAME, SF_SIZE]),
+  }
+
 # disk template types
 DT_DISKLESS = "diskless"
 DT_PLAIN = "plain"

lib/storage.py

@@ -31,13 +31,6 @@ from ganeti import constants
 from ganeti import utils
 
 
-COL_NAME = "name"
-COL_SIZE = "size"
-COL_FREE = "free"
-COL_USED = "used"
-COL_ALLOCATABLE = "allocatable"
-
-
 def _ParseSize(value):
   return int(round(float(value), 0))
 
@@ -102,24 +95,25 @@ class FileStorage(_Base):
     values = []
 
     # Pre-calculate information in case it's requested more than once
-    if COL_USED in fields:
+    if constants.SF_USED in fields:
       dirsize = utils.CalculateDirectorySize(path)
     else:
       dirsize = None
 
-    if COL_FREE in fields:
+    if constants.SF_FREE in fields:
       fsfree = utils.GetFreeFilesystemSpace(path)
     else:
       fsfree = None
 
+    # Make sure to update constants.VALID_STORAGE_FIELDS when changing fields.
     for field_name in fields:
-      if field_name == COL_NAME:
+      if field_name == constants.SF_NAME:
         values.append(path)
 
-      elif field_name == COL_USED:
+      elif field_name == constants.SF_USED:
         values.append(dirsize)
 
-      elif field_name == COL_FREE:
+      elif field_name == constants.SF_FREE:
         values.append(fsfree)
 
       else:
@@ -293,12 +287,15 @@ class LvmPvStorage(_LvmBase):
       return False
 
   LIST_COMMAND = "pvs"
+
+  # Make sure to update constants.VALID_STORAGE_FIELDS when changing field
+  # definitions.
   LIST_FIELDS = [
-    (COL_NAME, "pv_name", None),
-    (COL_SIZE, "pv_size", _ParseSize),
-    (COL_USED, "pv_used", _ParseSize),
-    (COL_FREE, "pv_free", _ParseSize),
-    (COL_ALLOCATABLE, "pv_attr", _GetAllocatable),
+    (constants.SF_NAME, "pv_name", None),
+    (constants.SF_SIZE, "pv_size", _ParseSize),
+    (constants.SF_USED, "pv_used", _ParseSize),
+    (constants.SF_FREE, "pv_free", _ParseSize),
+    (constants.SF_ALLOCATABLE, "pv_attr", _GetAllocatable),
     ]
 
 
@@ -307,9 +304,12 @@ class LvmVgStorage(_LvmBase):
 
   """
   LIST_COMMAND = "vgs"
+
+  # Make sure to update constants.VALID_STORAGE_FIELDS when changing field
+  # definitions.
   LIST_FIELDS = [
-    (COL_NAME, "vg_name", None),
-    (COL_SIZE, "vg_size", _ParseSize),
+    (constants.SF_NAME, "vg_name", None),
+    (constants.SF_SIZE, "vg_size", _ParseSize),
     ]