import unittest
from fcntl import flock, LOCK_EX, LOCK_SH, LOCK_UN
import contextlib as clib
+import subprocess
-class struct(object):
+class InvirtConfigError(AttributeError):
+ pass
+
+class struct(dict):
'A simple namespace object.'
- def __init__(self, d = {}, **kwargs):
- 'd is the dictionary to update my __dict__ with.'
- self.__dict__.update(d)
- self.__dict__.update(kwargs)
+ def __init__(self, d = {}, __prefix = None, __default=None, **kwargs):
+ super(struct, self).__init__(d)
+ self.__prefix = __prefix
+ self.__default = __default
+ self.update(kwargs)
+ def __getattr__(self, key):
+ try:
+ return self[key]
+ except KeyError:
+ if self.__default is None:
+ # 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,))
+ else:
+ return struct({}, '', self.__default)
-def dicts2struct(x):
+def dicts2struct(x, prefix = None, default = 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), default))
+ for k,v in x.iteritems()),
+ prefix,
+ default)
elif type(x) == list:
- return [dicts2struct(v) for v in x]
+ return [dicts2struct(v, newprefix(i), default)
+ for i, v in enumerate(x)]
+ elif x is None:
+ return struct({}, prefix, default)
else:
return x
finally:
flock(f, LOCK_UN)
+def captureOutput(popen_args, stdin_str=None, *args, **kwargs):
+ """Capture stdout from a command.
+
+ This method will proxy the arguments to subprocess.Popen. It
+ returns the output from the command if the call succeeded and
+ raises an exception if the process returns a non-0 value.
+
+ This is intended to be a variant on the subprocess.check_call
+ function that also allows you access to the output from the
+ command.
+ """
+ if 'stdin' not in kwargs:
+ kwargs['stdin'] = subprocess.PIPE
+ if 'stdout' not in kwargs:
+ kwargs['stdout'] = subprocess.PIPE
+ if 'stderr' not in kwargs:
+ kwargs['stderr'] = subprocess.PIPE
+ p = subprocess.Popen(popen_args, *args, **kwargs)
+ out, err = p.communicate(stdin_str)
+ if p.returncode:
+ raise subprocess.CalledProcessError(p.returncode, '%s, stdout: %s, stderr: %s' %
+ (popen_args, out, err))
+ return out
+
+#
+# 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'])
self.assertEqual(structs.list[0], dicts['list'][0])
self.assertEqual(structs.list[1].key, dicts['list'][1]['key'])
+ self.assertEqual(set(structs), set(['atom', 'dict', 'list']))
if __name__ == '__main__':
unittest.main()