1 | from __future__ import with_statement |
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2 | |
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3 | import unittest |
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4 | from fcntl import flock, LOCK_EX, LOCK_SH, LOCK_UN |
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5 | import contextlib as clib |
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6 | |
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7 | class InvirtConfigError(AttributeError): |
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8 | pass |
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9 | |
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10 | class struct(object): |
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11 | 'A simple namespace object.' |
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12 | def __init__(self, d = {}, __prefix = None, **kwargs): |
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13 | 'd is the dictionary or the items-iterable to update my __dict__ with.' |
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14 | self.__dict__.update(d) |
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15 | self.__dict__.update(kwargs) |
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16 | self.__prefix = __prefix |
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17 | def __getattr__(self, key): |
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18 | # XX ideally these would point a frame higher on the stack. |
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19 | prefix = self.__prefix |
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20 | if prefix is not None: |
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21 | raise InvirtConfigError('missing configuration variable %s%s' |
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22 | % (prefix, key)) |
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23 | else: |
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24 | raise AttributeError("anonymous struct has no member '%s'" |
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25 | % (key,)) |
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26 | |
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27 | def dicts2struct(x, prefix = None): |
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28 | """ |
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29 | Given a tree of lists/dicts, perform a deep traversal to transform all the |
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30 | dicts to structs. |
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31 | """ |
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32 | if prefix is not None: |
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33 | def newprefix(k): return prefix + str(k) + '.' |
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34 | else: |
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35 | def newprefix(k): return prefix |
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36 | if type(x) == dict: |
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37 | return struct(((k, dicts2struct(v, newprefix(k))) |
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38 | for k,v in x.iteritems()), |
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39 | prefix) |
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40 | elif type(x) == list: |
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41 | return [dicts2struct(v, newprefix(i)) for i, v in enumerate(x)] |
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42 | else: |
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43 | return x |
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44 | |
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45 | @clib.contextmanager |
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46 | def lock_file(path, exclusive = True): |
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47 | with clib.closing(file(path, 'w')) as f: |
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48 | if exclusive: |
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49 | locktype = LOCK_EX |
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50 | else: |
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51 | locktype = LOCK_SH |
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52 | flock(f, locktype) |
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53 | try: |
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54 | yield |
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55 | finally: |
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56 | flock(f, LOCK_UN) |
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57 | |
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58 | # |
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59 | # Exceptions. |
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60 | # |
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61 | |
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62 | class InvalidInput(Exception): |
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63 | """Exception for user-provided input is invalid but maybe in good faith. |
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64 | |
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65 | This would include setting memory to negative (which might be a |
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66 | typo) but not setting an invalid boot CD (which requires bypassing |
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67 | the select box). |
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68 | """ |
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69 | def __init__(self, err_field, err_value, expl=None): |
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70 | Exception.__init__(self, expl) |
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71 | self.err_field = err_field |
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72 | self.err_value = err_value |
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73 | |
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74 | class CodeError(Exception): |
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75 | """Exception for internal errors or bad faith input.""" |
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76 | pass |
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77 | |
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78 | # |
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79 | # Tests. |
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80 | # |
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81 | |
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82 | class common_tests(unittest.TestCase): |
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83 | def test_dicts2structs(self): |
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84 | dicts = { |
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85 | 'atom': 0, |
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86 | 'dict': { 'atom': 'atom', 'list': [1,2,3] }, |
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87 | 'list': [ 'atom', {'key': 'value'} ] |
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88 | } |
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89 | structs = dicts2struct(dicts, '') |
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90 | self.assertEqual(structs.atom, dicts['atom']) |
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91 | self.assertEqual(structs.dict.atom, dicts['dict']['atom']) |
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92 | self.assertEqual(structs.dict.list, dicts['dict']['list']) |
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93 | self.assertEqual(structs.list[0], dicts['list'][0]) |
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94 | self.assertEqual(structs.list[1].key, dicts['list'][1]['key']) |
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95 | |
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96 | if __name__ == '__main__': |
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97 | unittest.main() |
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