from fcntl import flock, LOCK_EX, LOCK_SH, LOCK_UN
import contextlib as clib
+class InvirtConfigError(AttributeError):
+ pass
+
class struct(object):
'A simple namespace object.'
- def __init__(self, d = {}, **kwargs):
- 'd is the dictionary to update my __dict__ with.'
+ def __init__(self, d = {}, __prefix = None, **kwargs):
+ 'd is the dictionary or the items-iterable to update my __dict__ with.'
self.__dict__.update(d)
self.__dict__.update(kwargs)
+ self.__prefix = __prefix
+ def __getattr__(self, key):
+ # XX ideally these would point a frame higher on the stack.
+ prefix = self.__prefix
+ if prefix is not None:
+ raise InvirtConfigError('missing configuration variable %s%s'
+ % (prefix, key))
+ else:
+ raise AttributeError("anonymous struct has no member '%s'"
+ % (key,))
-def dicts2struct(x):
+def dicts2struct(x, prefix = None):
"""
Given a tree of lists/dicts, perform a deep traversal to transform all the
dicts to structs.
"""
+ if prefix is not None:
+ def newprefix(k): return prefix + str(k) + '.'
+ else:
+ def newprefix(k): return prefix
if type(x) == dict:
- return struct((k, dicts2struct(v)) for k,v in x.iteritems())
+ return struct(((k, dicts2struct(v, newprefix(k)))
+ for k,v in x.iteritems()),
+ prefix)
elif type(x) == list:
- return [dicts2struct(v) for v in x]
+ return [dicts2struct(v, newprefix(i)) for i, v in enumerate(x)]
+ elif x is None:
+ return struct({}, prefix)
else:
return x
flock(f, LOCK_UN)
#
+# Exceptions.
+#
+
+class InvalidInput(Exception):
+ """Exception for user-provided input is invalid but maybe in good faith.
+
+ This would include setting memory to negative (which might be a
+ typo) but not setting an invalid boot CD (which requires bypassing
+ the select box).
+ """
+ def __init__(self, err_field, err_value, expl=None):
+ Exception.__init__(self, expl)
+ self.err_field = err_field
+ self.err_value = err_value
+
+class CodeError(Exception):
+ """Exception for internal errors or bad faith input."""
+ pass
+
+#
# Tests.
#
'dict': { 'atom': 'atom', 'list': [1,2,3] },
'list': [ 'atom', {'key': 'value'} ]
}
- structs = dicts2struct(dicts)
+ structs = dicts2struct(dicts, '')
self.assertEqual(structs.atom, dicts['atom'])
self.assertEqual(structs.dict.atom, dicts['dict']['atom'])
self.assertEqual(structs.dict.list, dicts['dict']['list'])