chiark / gitweb /
httpauth.py: Don't crash if Base-64 decoding of the CSRF token fails.
[chopwood] / config.py
CommitLineData
a2916c06
MW
1### -*-python-*-
2###
3### Configuration handling
4###
5### (c) 2013 Mark Wooding
6###
7
8###----- Licensing notice ---------------------------------------------------
9###
10### This file is part of Chopwood: a password-changing service.
11###
12### Chopwood is free software; you can redistribute it and/or modify
13### it under the terms of the GNU Affero General Public License as
14### published by the Free Software Foundation; either version 3 of the
15### License, or (at your option) any later version.
16###
17### Chopwood is distributed in the hope that it will be useful,
18### but WITHOUT ANY WARRANTY; without even the implied warranty of
19### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20### GNU Affero General Public License for more details.
21###
22### You should have received a copy of the GNU Affero General Public
23### License along with Chopwood; if not, see
24### <http://www.gnu.org/licenses/>.
25
26from __future__ import with_statement
27
28import os as OS; ENV = OS.environ
29import sys as SYS
30import types as TY
31
32from auto import PACKAGE, VERSION
33
34### Configuration is done by interpreting a file of Python code. We expect
35### the code to define a number of variables in its global scope. We import
36### a number of identifiers (named in the `EXPORT' list) to this module, and
37### also our entire parent module as `chpwd'.
38
39## Names which ought to be exported to the configuration module.
40_EXPORT = {}
41
42## The configuration module.
43CFG = TY.ModuleType('chpwd_config')
44
45## A list of hooks to call once configuration is complete.
46_HOOKS = []
47def hook(func):
48 """Decorator for post-configuration hooks."""
49 _HOOKS.append(func)
50 return func
51
52## A suitable set of defaults.
53DEFAULTS = {}
54
55def export(*names, **kw):
56 """
57 Export the names to the configuration module from the caller's environment.
58 """
59
60 ## Find the caller's global environment. Please don't try this at home.
61 try: raise Exception
62 except: tb = SYS.exc_info()[2]
63 env = tb.tb_frame.f_back.f_globals
64
65 ## Export things.
66 for name in names:
67 _EXPORT[name] = env[name]
68 _EXPORT.update(kw)
69
70## Some things to export for sure.
71export('PACKAGE', 'VERSION', 'ENV', CONF = SYS.modules[__name__])
72
73def loadconfig(config):
74 """
75 Load the configuration, populating the `CFG' module with settings.
76 """
77
78 ## Make a new module for the configuration, and import ourselves into it.
79 d = CFG.__dict__
80 d.update(_EXPORT)
81 d.update(DEFAULTS)
82
83 ## And run the configuration code.
84 with open(config) as f:
85 exec f in d
86
87 ## Run the hooks.
88 for func in _HOOKS:
89 func()
90
91###----- That's all, folks --------------------------------------------------