Canonicalize size and ptable values on action creation.

curtin allows parition/lv sizes to be specified as strings or integers.
To avoid depending on whichever extract_storage_config gives us back,
canonicalize them to integers when creating an action. Similarly, curtin
accepts as synonyms "dos" and "msdos" for ptable; here we canonicalize
them both to "msdos".

subiquity/models/filesystem.py

@@ -25,6 +25,8 @@ import pathlib
 import platform
 import sys
 
+from curtin.util import human2bytes
+
 log = logging.getLogger('subiquity.models.filesystem')
 
 
@@ -235,6 +237,19 @@ class attributes:
     def const(value):
         return attr.ib(default=value)
 
+    @staticmethod
+    def size():
+        return attr.ib(converter=human2bytes)
+
+    @staticmethod
+    def ptable():
+
+        def conv(val):
+            if val == "dos":
+                val = "msdos"
+            return val
+        return attr.ib(default=None, converter=conv)
+
 
 def asdict(inst):
     r = collections.OrderedDict()
@@ -479,7 +494,7 @@ class _Device(_Formattable, ABC):
 
 @fsobj("disk")
 class Disk(_Device):
-    ptable = attr.ib(default=None)
+    ptable = attributes.ptable()
     serial = attr.ib(default=None)
     path = attr.ib(default=None)
     model = attr.ib(default=None)
@@ -583,7 +598,7 @@ class Disk(_Device):
 @fsobj("partition")
 class Partition(_Formattable):
     device = attributes.ref(backlink="_partitions")  # Disk
-    size = attr.ib()
+    size = attributes.size()
 
     wipe = attr.ib(default=None)
     flag = attr.ib(default=None)
@@ -660,7 +675,7 @@ class Raid(_Device):
     spare_devices = attributes.reflist(backlink="_constructed_device")
 
     preserve = attr.ib(default=False)
-    ptable = attr.ib(default=None)
+    ptable = attributes.ptable()
 
     @property
     def size(self):
@@ -778,7 +793,7 @@ class LVM_VolGroup(_Device):
 class LVM_LogicalVolume(_Formattable):
     name = attr.ib()
     volgroup = attributes.ref(backlink="_partitions")  # LVM_VolGroup
-    size = attr.ib()
+    size = attributes.size()
 
     preserve = attr.ib(default=False)