Lazy sources - after submodules #96
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,38 +1,146 @@ | ||
| from __future__ import division, absolute_import, print_function | ||
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| import os | ||
| import functools | ||
| from .util import BASESTRING | ||
| from . import yaml_util | ||
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| __all__ = ['ConfigSource', 'YamlSource'] | ||
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| UNSET = object() # sentinel | ||
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| def _load_first(func): | ||
| '''Call self.load() before the function is called - used for lazy source | ||
| loading''' | ||
| def inner(self, *a, **kw): | ||
| self.load() | ||
| return func(self, *a, **kw) | ||
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| try: | ||
| return functools.wraps(func)(inner) | ||
| except AttributeError: | ||
| # in v2 they don't ignore missing attributes | ||
| # v3: https://github.com/python/cpython/blob/3.8/Lib/functools.py | ||
| # v2: https://github.com/python/cpython/blob/2.7/Lib/functools.py | ||
| inner.__name__ = func.__name__ | ||
| return inner | ||
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| class ConfigSource(dict): | ||
| '''A dictionary augmented with metadata about the source of the | ||
| configuration. | ||
| ''' | ||
|
There was a problem hiding this comment. Likewise with the docstring """s. |
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| def __getattribute__(self, k): | ||
| x = super(ConfigSource, self).__getattribute__(k) | ||
| if k == 'keys': | ||
| # HACK: in 2.7, it appears that doing dict(source) only checks for | ||
| # the existance of a keys attribute and doesn't actually cast | ||
| # to a dict, so we never get the chance to load. My goal | ||
| # is to remove this entirely ASAP. | ||
| x() | ||
| return x | ||
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| def __init__(self, value=UNSET, filename=None, default=False, | ||
| retry=False): | ||
| # track whether a config source has been set yet | ||
| self.loaded = value is not UNSET | ||
| self.retry = retry | ||
| super(ConfigSource, self).__init__(value if self.loaded else {}) | ||
| if (filename is not None | ||
| and not isinstance(filename, BASESTRING)): | ||
| raise TypeError(u'filename must be a string or None') | ||
| self.filename = filename | ||
| self.default = default | ||
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| def __repr__(self): | ||
| return '{}({}, filename={}, default={})'.format( | ||
| self.__class__.__name__, | ||
| dict.__repr__(self) | ||
| if self.loaded else '[Unloaded]' | ||
| if self.exists else "[Source doesn't exist]", | ||
| self.filename, self.default) | ||
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| @property | ||
| def exists(self): | ||
| """Does this config have access to usable configuration values?""" | ||
| return self.loaded or self.filename and os.path.isfile(self.filename) | ||
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| def load(self): | ||
| """Ensure that the source is loaded.""" | ||
| if not self.loaded: | ||
| self.config_dir() | ||
| self.loaded = self._load() is not False or not self.retry | ||
| return self | ||
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| def _load(self): | ||
| """Load config from source and update self. | ||
| If it doesn't load, return False to keep it marked as unloaded. | ||
| Otherwise it will be assumed to be loaded. | ||
| """ | ||
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| def config_dir(self, create=True): | ||
| """Create the config dir, if there's a filename associated with the | ||
| source.""" | ||
| if self.filename: | ||
| dirname = os.path.dirname(self.filename) | ||
| if create and dirname and not os.path.isdir(dirname): | ||
| os.makedirs(dirname) | ||
| return dirname | ||
| return None | ||
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| # overriding dict methods so that the configuration is loaded before any | ||
| # of them are run | ||
| __getitem__ = _load_first(dict.__getitem__) | ||
| __iter__ = _load_first(dict.__iter__) | ||
| # __len__ = _load_first(dict.__len__) | ||
| keys = _load_first(dict.keys) | ||
| values = _load_first(dict.values) | ||
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| @classmethod | ||
| def isoftype(cls, value, **kw): | ||
| return False | ||
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| @classmethod | ||
| def of(cls, value, **kw): | ||
| """Try to convert value to a `ConfigSource` object. This lets a | ||
| function accept values that are convertable to a source. | ||
| """ | ||
| # ignore if already a source | ||
| if isinstance(value, ConfigSource): | ||
| return value | ||
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| # if it's a yaml file | ||
| if YamlSource.isoftype(value, **kw): | ||
| return YamlSource(value, **kw) | ||
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| # if it's an explicit config dict | ||
| if isinstance(value, dict): | ||
| return ConfigSource(value, **kw) | ||
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| # none of the above | ||
| raise TypeError( | ||
| u'ConfigSource.of value unable to cast to ConfigSource.') | ||
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| class YamlSource(ConfigSource): | ||
| """A config source pulled from yaml files.""" | ||
| EXTENSIONS = '.yaml', '.yml' | ||
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| def __init__(self, filename=None, value=UNSET, optional=False, | ||
| loader=yaml_util.Loader, **kw): | ||
| self.optional = optional | ||
| self.loader = loader | ||
| super(YamlSource, self).__init__(value, filename, **kw) | ||
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| @classmethod | ||
| def isoftype(cls, value, **kw): | ||
| return (isinstance(value, BASESTRING) | ||
| and os.path.splitext(value)[1] in YamlSource.EXTENSIONS) | ||
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| def _load(self): | ||
| '''Load the file if it exists.''' | ||
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| if self.optional and not os.path.isfile(self.filename): | ||
| return False | ||
| self.update(yaml_util.load_yaml(self.filename, loader=self.loader)) | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,54 @@ | ||
| from __future__ import division, absolute_import, print_function | ||
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| import confuse | ||
| import confuse.yaml_util | ||
| import unittest | ||
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| class ConfigSourceTest(unittest.TestCase): | ||
| def _load_yaml(self, file, **kw): | ||
| return {'a': 5, 'file': file} | ||
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| def setUp(self): | ||
| self._orig_load_yaml = confuse.yaml_util.load_yaml | ||
| confuse.yaml_util.load_yaml = self._load_yaml | ||
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| def tearDown(self): | ||
| confuse.yaml_util.load_yaml = self._orig_load_yaml | ||
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| def test_source_conversion(self): | ||
| # test pure dict source | ||
| src = confuse.ConfigSource.of({'a': 5}) | ||
| self.assertIsInstance(src, confuse.ConfigSource) | ||
| self.assertEqual(src.loaded, True) | ||
| # test yaml filename | ||
| src = confuse.ConfigSource.of('asdf/asfdd.yml') | ||
| self.assertIsInstance(src, confuse.YamlSource) | ||
| self.assertEqual(src.loaded, False) | ||
| self.assertEqual(src.exists, False) | ||
| self.assertEqual(src.config_dir(create=False), 'asdf') | ||
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| def test_explicit_load(self): | ||
| src = confuse.ConfigSource.of('asdf.yml') | ||
| self.assertEqual(src.loaded, False) | ||
| src.load() | ||
| self.assertEqual(src.loaded, True) | ||
| self.assertEqual(src['a'], 5) | ||
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| def test_load_getitem(self): | ||
| src = confuse.ConfigSource.of('asdf.yml') | ||
| self.assertEqual(src.loaded, False) | ||
| self.assertEqual(src['a'], 5) | ||
| self.assertEqual(src.loaded, True) | ||
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| def test_load_cast_dict(self): | ||
| src = confuse.ConfigSource.of('asdf.yml') | ||
| self.assertEqual(src.loaded, False) | ||
| self.assertEqual(dict(src), {'a': 5, 'file': 'asdf.yml'}) | ||
| self.assertEqual(src.loaded, True) | ||
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| def test_load_keys(self): | ||
| src = confuse.ConfigSource.of('asdf.yml') | ||
| self.assertEqual(src.loaded, False) | ||
| self.assertEqual(set(src.keys()), {'a', 'file'}) | ||
| self.assertEqual(src.loaded, True) |
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Let's switch this to """ for uniformity.