h5config/storage/yaml.py

   1 # Copyright (C) 2011 W. Trevor King <wking@drexel.edu>
   2 #
   3 # This file is part of h5config.
   4 #
   5 # h5config is free software; you can redistribute it and/or modify it
   6 # under the terms of the GNU General Public License as published by the
   7 # Free Software Foundation, either version 3 of the License, or (at your
   8 # option) any later version.
   9 #
  10 # h5config is distributed in the hope that it will be useful, but
  11 # WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 # General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with h5config.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 """HDF5 backend implementation
  19 """
  20
  21 from __future__ import absolute_import
  22
  23 import os.path as _os_path
  24 import types as _types
  25
  26 import yaml as _yaml  # global PyYAML module
  27
  28 from .. import LOG as _LOG
  29 from .. import config as _config
  30 from . import FileStorage as _FileStorage
  31
  32
  33 class _YAMLDumper (_yaml.SafeDumper):
  34     def represent_bool(self, data):
  35         "Use yes/no instead of the default true/false"
  36         if data:
  37             value = u'yes'
  38         else:
  39             value = u'no'
  40         return self.represent_scalar(u'tag:yaml.org,2002:bool', value)
  41
  42
  43 _YAMLDumper.add_representer(bool, _YAMLDumper.represent_bool)
  44
  45
  46 class YAML_Storage (_FileStorage):
  47     """Back a `Config` class with a YAML file.
  48
  49     >>> import os
  50     >>> from ..test import TestConfig
  51     >>> import os.path
  52     >>> import tempfile
  53     >>> fd,filename = tempfile.mkstemp(
  54     ...     suffix='.'+YAML_Storage.extension, prefix='pypiezo-')
  55     >>> os.close(fd)
  56
  57     >>> c = TestConfig(storage=YAML_Storage(filename=filename))
  58     >>> c.load()
  59
  60     Saving writes all the config values to disk.
  61
  62     >>> c['alive'] = True
  63     >>> c.save()
  64     >>> print open(filename, 'r').read()  # doctest: +REPORT_UDIFF
  65     age: 1.3
  66     alive: yes
  67     bids:
  68     - 5.4
  69     - 3.2
  70     - 1
  71     children: ''
  72     daisies: 13
  73     name: ''
  74     species: Norwegian Blue
  75     spouse: ''
  76     <BLANKLINE>
  77
  78     Loading reads the config files from disk.
  79
  80     >>> c.clear()
  81     >>> c['alive']
  82     False
  83     >>> c.load()
  84     >>> c['alive']
  85     True
  86
  87     Cleanup our temporary config file.
  88
  89     >>> os.remove(filename)
  90     """
  91     extension = 'yaml'
  92     dumper = _YAMLDumper
  93
  94     def _load(self, config):
  95         if not _os_path.exists(self._filename):
  96             open(self._filename, 'a').close()
  97         with open(self._filename, 'r') as f:
  98             data = _yaml.safe_load(f)
  99         if data == None:
 100             return  # empty file
 101         return self._from_dict(config, data)
 102
 103     @staticmethod
 104     def _from_dict(config, data):
 105         settings = dict([(s.name, s) for s in config.settings])
 106         for key,value in data.iteritems():
 107             setting = settings[key]
 108             if isinstance(setting, (_config.BooleanSetting,
 109                                     _config.NumericSetting,
 110                                     _config.FloatListSetting)):
 111                 if isinstance(value, _types.StringTypes):
 112                     # older versions of h5config
 113                     value = s.convert_from_text(value)
 114                 v = value
 115             elif isinstance(setting, _config.ConfigListSetting) and value:
 116                 values = []
 117                 for v in value:
 118                     values.append(YAML_Storage._from_dict(
 119                             setting.config_class(), v))
 120                 v = values
 121             elif isinstance(setting, _config.ConfigSetting) and value:
 122                 v = YAML_Storage._from_dict(setting.config_class(), value)
 123             else:
 124                 v = setting.convert_from_text(value)
 125             config[key] = v
 126         return config
 127
 128     def _save(self, config):
 129         data = self._to_dict(config)
 130         with open(self._filename, 'w') as f:
 131             _yaml.dump(data, stream=f, Dumper=self.dumper,
 132                        default_flow_style=False)
 133
 134     @staticmethod
 135     def _to_dict(config):
 136         data = {}
 137         settings = dict([(s.name, s) for s in config.settings])
 138         for key,value in config.iteritems():
 139             if key in settings:
 140                 setting = settings[key]
 141                 if isinstance(setting, (_config.BooleanSetting,
 142                                         _config.NumericSetting,
 143                                         _config.FloatListSetting)):
 144                     v = value
 145                 elif isinstance(setting, _config.ConfigListSetting) and value:
 146                     values = []
 147                     for v in value:
 148                         values.append(YAML_Storage._to_dict(v))
 149                     v = values
 150                 elif isinstance(setting, _config.ConfigSetting) and value:
 151                     v = YAML_Storage._to_dict(value)
 152                 else:
 153                     v = setting.convert_to_text(value)
 154                 data[key] = v
 155         return data