summaryrefslogtreecommitdiffstats
path: root/ipalib/config.py
blob: dc5d35f8b4b6635d24b4759329586df4057cf702 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
# Authors:
#   Martin Nagy <mnagy@redhat.com>
#
# Copyright (C) 2008  Red Hat
# see file 'COPYING' for use and warranty information
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2 only
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""
Basic configuration management.

This module handles the reading and representation of basic local settings.
It will also take care of settings that can be discovered by different
methods, such as DNS.
"""

from ConfigParser import RawConfigParser, ParsingError
from types import NoneType
import os
from os import path
import sys
from constants import CONFIG_SECTION
from constants import TYPE_ERROR, OVERRIDE_ERROR, SET_ERROR, DEL_ERROR


class Env(object):
    """
    Store and retrieve environment variables.

    First an foremost, the `Env` class provides a handy container for
    environment variables.  These variables can be both set *and* retrieved
    either as attributes *or* as dictionary items.

    For example, you can set a variable as an attribute:

    >>> env = Env()
    >>> env.attr = 'I was set as an attribute.'
    >>> env.attr
    'I was set as an attribute.'
    >>> env['attr']  # Also retrieve as a dictionary item
    'I was set as an attribute.'

    Or you can set a variable as a dictionary item:

    >>> env['item'] = 'I was set as a dictionary item.'
    >>> env['item']
    'I was set as a dictionary item.'
    >>> env.item  # Also retrieve as an attribute
    'I was set as a dictionary item.'

    The variable values can be ``str`` or ``int`` instances, or the ``True``,
    ``False``, or ``None`` constants.  When the value provided is an ``str``
    instance, some limited automatic type conversion is performed, which allows
    values of specific types to be set easily from configuration files or
    command-line options.

    So in addition to their actual values, the ``True``, ``False``, and ``None``
    constants can be specified with an ``str`` equal to what ``repr()`` would
    return.  For example:

    >>> env.true = True
    >>> env.also_true = 'True'  # Equal to repr(True)
    >>> env.true
    True
    >>> env.also_true
    True

    Note that the automatic type conversion is case sensitive.  For example:

    >>> env.false = 'false'  # Not equal to repr(False)!
    >>> env.false
    'false'

    If an ``str`` value looks like an integer, it's automatically converted to
    the ``int`` type.  For example:

    >>> env.lucky = '7'
    >>> env.lucky
    7

    Leading and trailing white-space is automatically stripped from ``str``
    values.  For example:

    >>> env.message = '  Hello!  '  # Surrounded by double spaces
    >>> env.message
    'Hello!'
    >>> env.number = ' 42 '  # Still converted to an int
    >>> env.number
    42
    >>> env.actually_false = ' False '  # Still equal to repr(False)
    >>> env.actually_false
    False

    Also, empty ``str`` instances are converted to ``None``.  For example:

    >>> env.empty = ''
    >>> env.empty is None
    True

    `Env` variables are all set-once (first-one-wins).  Once a variable has been
    set, trying to override it will raise an ``AttributeError``.  For example:

    >>> env.date = 'First'
    >>> env.date = 'Second'
    Traceback (most recent call last):
      ...
    AttributeError: cannot override Env.date value 'First' with 'Second'

    An `Env` instance can be *locked*, after which no further variables can be
    set.  Trying to set variables on a locked `Env` instance will also raise
    an ``AttributeError``.  For example:

    >>> env = Env()
    >>> env.okay = 'This will work.'
    >>> env.__lock__()
    >>> env.nope = 'This wont work!'
    Traceback (most recent call last):
      ...
    AttributeError: locked: cannot set Env.nope to 'This wont work!'

    `Env` instances also provide standard container emulation for membership
    testing, counting, and iteration.  For example:

    >>> env = Env()
    >>> 'key1' in env  # Has key1 been set?
    False
    >>> env.key1 = 'value 1'
    >>> 'key1' in env
    True
    >>> env.key2 = 'value 2'
    >>> len(env)  # How many variables have been set?
    2
    >>> list(env)  # What variables have been set?
    ['key1', 'key2']

    Lastly, in addition to all the handy container functionality, the `Env`
    class provides high-level methods for bootstraping a fresh `Env` instance
    into one containing all the run-time and configuration information needed
    by the built-in freeIPA plugins.

    These are the `Env` bootstraping methods, in the order they must be called:

        1. `Env._bootstrap()` - initialize the run-time variables and then
           merge-in variables specified on the command-line.

        2. `Env._finalize_core()` - merge-in variables from the configuration
           files and then merge-in variables from the internal defaults, after
           which at least all the standard variables will be set.  After this
           method is called, the plugins will be loaded, during which 3rd-party
           plugins can set additional variables they may need.

        3. `Env._finalize()` - one last chance to merge-in variables and then
           the instance is locked.  After this method is called, no more
           environment variables can be set during the remaining life of the
           process.

    However, normally none of the above methods are called directly and instead
    only `plugable.API.bootstrap()` is called, which itself takes care of
    correctly calling the `Env` bootstrapping methods.
    """

    __locked = False

    def __init__(self):
        object.__setattr__(self, '_Env__d', {})
        object.__setattr__(self, '_Env__done', set())

    def __lock__(self):
        """
        Prevent further changes to environment.
        """
        if self.__locked is True:
            raise StandardError(
                '%s.__lock__() already called' % self.__class__.__name__
            )
        object.__setattr__(self, '_Env__locked', True)

    def __islocked__(self):
        """
        Return ``True`` if locked.
        """
        return self.__locked

    def __setattr__(self, name, value):
        """
        Set the attribute named ``name`` to ``value``.

        This just calls `Env.__setitem__()`.
        """
        self[name] = value

    def __setitem__(self, key, value):
        """
        Set ``key`` to ``value``.
        """
        # FIXME: the key should be checked with check_name()
        if self.__locked:
            raise AttributeError(
                SET_ERROR % (self.__class__.__name__, key, value)
            )
        if key in self.__d:
            raise AttributeError(OVERRIDE_ERROR %
                (self.__class__.__name__, key, self.__d[key], value)
            )
        assert not hasattr(self, key)
        if isinstance(value, basestring):
            value = str(value.strip())
            m = {
                'True': True,
                'False': False,
                'None': None,
                '': None,
            }
            if value in m:
                value = m[value]
            elif value.isdigit():
                value = int(value)
        assert type(value) in (str, int, bool, NoneType)
        object.__setattr__(self, key, value)
        self.__d[key] = value

    def __getitem__(self, key):
        """
        Return the value corresponding to ``key``.
        """
        return self.__d[key]

    def __delattr__(self, name):
        """
        Raise AttributeError (deletion is never allowed).
        """
        raise AttributeError(
            DEL_ERROR % (self.__class__.__name__, name)
        )

    def __contains__(self, key):
        """
        Return True if instance contains ``key``; otherwise return False.
        """
        return key in self.__d

    def __len__(self):
        """
        Return number of variables currently set.
        """
        return len(self.__d)

    def __iter__(self):
        """
        Iterate through keys in ascending order.
        """
        for key in sorted(self.__d):
            yield key

    def __doing(self, name):
        if name in self.__done:
            raise StandardError(
                '%s.%s() already called' % (self.__class__.__name__, name)
            )
        self.__done.add(name)

    def __do_if_not_done(self, name):
        if name not in self.__done:
            getattr(self, name)()

    def _isdone(self, name):
        return name in self.__done

    def _bootstrap(self, **overrides):
        """
        Initialize basic environment.

        In addition to certain run-time information, this method will
        initialize only enough environment information to determine whether
        IPA is running in-tree, what the context is, and the location of the
        configuration file.
        """
        self.__doing('_bootstrap')

        # Set run-time variables:
        self.ipalib = path.dirname(path.abspath(__file__))
        self.site_packages = path.dirname(self.ipalib)
        self.script = path.abspath(sys.argv[0])
        self.bin = path.dirname(self.script)
        self.home = path.abspath(os.environ['HOME'])
        self.dot_ipa = path.join(self.home, '.ipa')

        for (key, value) in overrides.iteritems():
            self[key] = value
        if 'in_tree' not in self:
            if self.bin == self.site_packages and \
                    path.isfile(path.join(self.bin, 'setup.py')):
                self.in_tree = True
            else:
                self.in_tree = False
        if 'context' not in self:
            self.context = 'default'
        if self.in_tree:
            base = self.dot_ipa
        else:
            base = path.join('/', 'etc', 'ipa')
        if 'conf' not in self:
            self.conf = path.join(base, '%s.conf' % self.context)
        if 'conf_default' not in self:
            self.conf_default = path.join(base, 'default.conf')
        if 'conf_dir' not in self:
            self.conf_dir = base

    def _finalize_core(self, **defaults):
        """
        Complete initialization of standard IPA environment.

        After this method is called, the all environment variables
        used by all the built-in plugins will be available.

        This method should be called before loading any plugins.  It will
        automatically call `Env._bootstrap()` if it has not yet been called.

        After this method has finished, the `Env` instance is still writable
        so that 3rd-party plugins can set variables they may require as the
        plugins are registered.
        """
        self.__doing('_finalize_core')
        self.__do_if_not_done('_bootstrap')
        if self.__d.get('mode', None) != 'dummy':
            self._merge_config(self.conf)
            self._merge_config(self.conf_default)
        if 'in_server' not in self:
            self.in_server = (self.context == 'server')
        if 'log' not in self:
            name = '%s.log' % self.context
            if self.in_tree or self.context == 'cli':
                self.log = path.join(self.dot_ipa, 'log', name)
            else:
                self.log = path.join('/', 'var', 'log', 'ipa', name)
        for (key, value) in defaults.iteritems():
            if key not in self:
                self[key] = value

    def _finalize(self, **lastchance):
        """
        Finalize and lock environment.

        This method should be called after all plugins have been loaded and
        after `plugable.API.finalize()` has been called.  This method will
        automatically call `Env._finalize_core()` if it hasn't been called
        already, but in normal operation this would result in an exception
        being raised because the internal default values will not have been
        merged-in.

        After this method finishes, the `Env` instance will be locked and no
        more environment variables can be set.  Aside from unit-tests and
        example code, normally only one `Env` instance is created, which means
        no more variables can be set during the remaining life of the process.
        """
        self.__doing('_finalize')
        self.__do_if_not_done('_finalize_core')
        for (key, value) in lastchance.iteritems():
            if key not in self:
                self[key] = value
        self.__lock__()

    def _merge_config(self, conf_file):
        """
        Merge values from ``conf_file`` into this `Env`.
        """
        if not path.isfile(conf_file):
            return
        parser = RawConfigParser()
        try:
            parser.read(conf_file)
        except ParsingError:
            return
        if not parser.has_section(CONFIG_SECTION):
            parser.add_section(CONFIG_SECTION)
        items = parser.items(CONFIG_SECTION)
        if len(items) == 0:
            return
        i = 0
        for (key, value) in items:
            if key not in self:
                self[key] = value
                i += 1
        return (i, len(items))