Add Python 3 docker-compose recipe for MediaGoblin hacking.
[mediagoblin.git] / mediagoblin / init / config.py
... / ...
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1# GNU MediaGoblin -- federated, autonomous media hosting
2# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
3#
4# This program is free software: you can redistribute it and/or modify
5# it under the terms of the GNU Affero General Public License as published by
6# the Free Software Foundation, either version 3 of the License, or
7# (at your option) any later version.
8#
9# This program is distributed in the hope that it will be useful,
10# but WITHOUT ANY WARRANTY; without even the implied warranty of
11# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12# GNU Affero General Public License for more details.
13#
14# You should have received a copy of the GNU Affero General Public License
15# along with this program. If not, see <http://www.gnu.org/licenses/>.
16
17import copy
18import logging
19import os
20import pkg_resources
21
22from configobj import ConfigObj, flatten_errors
23from validate import Validator
24
25
26_log = logging.getLogger(__name__)
27
28
29CONFIG_SPEC_PATH = pkg_resources.resource_filename(
30 'mediagoblin', 'config_spec.ini')
31
32
33def _setup_defaults(config, config_path, extra_defaults=None):
34 """
35 Setup DEFAULTS in a config object from an (absolute) config_path.
36 """
37 extra_defaults = extra_defaults or {}
38
39 config.setdefault('DEFAULT', {})
40 config['DEFAULT']['here'] = os.path.dirname(config_path)
41 config['DEFAULT']['__file__'] = config_path
42
43 for key, value in extra_defaults.items():
44 config['DEFAULT'].setdefault(key, value)
45
46
47def read_mediagoblin_config(config_path, config_spec_path=CONFIG_SPEC_PATH):
48 """
49 Read a config object from config_path.
50
51 Does automatic value transformation based on the config_spec.
52 Also provides %(__file__)s and %(here)s values of this file and
53 its directory respectively similar to paste deploy.
54
55 Also reads for [plugins] section, appends all config_spec.ini
56 files from said plugins into the general config_spec specification.
57
58 This function doesn't itself raise any exceptions if validation
59 fails, you'll have to do something
60
61 Args:
62 - config_path: path to the config file
63 - config_spec_path: config file that provides defaults and value types
64 for validation / conversion. Defaults to mediagoblin/config_spec.ini
65
66 Returns:
67 A tuple like: (config, validation_result)
68 ... where 'conf' is the parsed config object and 'validation_result'
69 is the information from the validation process.
70 """
71 config_path = os.path.abspath(config_path)
72
73 # PRE-READ of config file. This allows us to fetch the plugins so
74 # we can add their plugin specs to the general config_spec.
75 config = ConfigObj(
76 config_path,
77 interpolation="ConfigParser")
78
79 # temporary bootstrap, just setup here and __file__... we'll do this again
80 _setup_defaults(config, config_path)
81
82 # Now load the main config spec
83 config_spec = ConfigObj(
84 config_spec_path,
85 encoding="UTF8", list_values=False, _inspec=True)
86
87 # HACK to get MediaGoblin running under Docker/Python 3. Without this line,
88 # `./bin/gmg dbupdate` fails as the configuration under 'DEFAULT' in
89 # config_spec still had %(here)s markers in it, when these should have been
90 # replaced with actual paths, resulting in
91 # "configobj.MissingInterpolationOption: missing option "here" in
92 # interpolation". This issue doesn't seem to appear when running on Guix,
93 # but adding this line also doesn't appear to cause problems on Guix.
94 _setup_defaults(config_spec, config_path)
95
96 # Set up extra defaults that will be pushed into the rest of the
97 # configs. This is a combined extrapolation of defaults based on
98 mainconfig_defaults = copy.copy(config_spec.get("DEFAULT", {}))
99 mainconfig_defaults.update(config["DEFAULT"])
100
101 plugins = config.get("plugins", {}).keys()
102 plugin_configs = {}
103
104 for plugin in plugins:
105 try:
106 plugin_config_spec_path = pkg_resources.resource_filename(
107 plugin, "config_spec.ini")
108 if not os.path.exists(plugin_config_spec_path):
109 continue
110
111 plugin_config_spec = ConfigObj(
112 plugin_config_spec_path,
113 encoding="UTF8", list_values=False, _inspec=True)
114 _setup_defaults(
115 plugin_config_spec, config_path, mainconfig_defaults)
116
117 if not "plugin_spec" in plugin_config_spec:
118 continue
119
120 plugin_configs[plugin] = plugin_config_spec["plugin_spec"]
121
122 except ImportError:
123 _log.warning(
124 "When setting up config section, could not import '%s'" %
125 plugin)
126
127 # append the plugin specific sections of the config spec
128 config_spec["plugins"] = plugin_configs
129
130 _setup_defaults(config_spec, config_path, mainconfig_defaults)
131
132 config = ConfigObj(
133 config_path,
134 configspec=config_spec,
135 encoding="UTF8",
136 interpolation="ConfigParser")
137
138 _setup_defaults(config, config_path, mainconfig_defaults)
139
140 # For now the validator just works with the default functions,
141 # but in the future if we want to add additional validation/configuration
142 # functions we'd add them to validator.functions here.
143 #
144 # See also:
145 # http://www.voidspace.org.uk/python/validate.html#adding-functions
146 validator = Validator()
147 validation_result = config.validate(validator, preserve_errors=True)
148
149 return config, validation_result
150
151
152REPORT_HEADER = u"""\
153There were validation problems loading this config file:
154--------------------------------------------------------
155"""
156
157
158def generate_validation_report(config, validation_result):
159 """
160 Generate a report if necessary of problems while validating.
161
162 Returns:
163 Either a string describing for a user the problems validating
164 this config or None if there are no problems.
165 """
166 report = []
167
168 # Organize the report
169 for entry in flatten_errors(config, validation_result):
170 # each entry is a tuple
171 section_list, key, error = entry
172
173 if key is not None:
174 section_list.append(key)
175 else:
176 section_list.append(u'[missing section]')
177
178 section_string = u':'.join(section_list)
179
180 if error == False:
181 # We don't care about missing values for now.
182 continue
183
184 report.append(u"%s = %s" % (section_string, error))
185
186 if report:
187 return REPORT_HEADER + u"\n".join(report)
188 else:
189 return None