models.py 18.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
# Copyright 2014 Budapest University of Technology and Economics (BME IK)
#
# This file is part of CIRCLE Cloud.
#
# CIRCLE 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, either version 3 of the License, or (at your option)
# any later version.
#
# CIRCLE 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 CIRCLE.  If not, see <http://www.gnu.org/licenses/>.

Őry Máté committed
18
from collections import deque
19
from contextlib import contextmanager
20
from functools import update_wrapper
21
from hashlib import sha224
22
from itertools import chain, imap
23
from logging import getLogger
24
from time import time
25
from warnings import warn
26

27
from django.contrib import messages
28
from django.contrib.auth.models import User
29
from django.core.cache import cache
30
from django.core.serializers.json import DjangoJSONEncoder
Dudás Ádám committed
31 32 33
from django.db.models import (
    CharField, DateTimeField, ForeignKey, NullBooleanField
)
34
from django.utils import timezone
35 36
from django.utils.encoding import force_text
from django.utils.functional import Promise
37 38
from django.utils.translation import ugettext_lazy as _, ugettext_noop
from jsonfield import JSONField
39

40
from manager.mancelery import celery
41 42
from model_utils.models import TimeStampedModel

43 44
logger = getLogger(__name__)

45

46 47 48 49
class WorkerNotFound(Exception):
    pass


50
def activitycontextimpl(act, on_abort=None, on_commit=None):
51
    try:
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
        try:
            yield act
        except HumanReadableException as e:
            result = e
            raise
        except BaseException as e:
            # BaseException is the common parent of Exception and
            # system-exiting exceptions, e.g. KeyboardInterrupt
            result = create_readable(
                ugettext_noop("Failure."),
                ugettext_noop("Unhandled exception: %(error)s"),
                error=unicode(e))
            raise
    except:
        logger.exception("Failed activity %s" % unicode(act))
67
        handler = None if on_abort is None else lambda a: on_abort(a, e)
68
        act.finish(succeeded=False, result=result, event_handler=handler)
69
        raise
70
    else:
71
        act.finish(succeeded=True, event_handler=on_commit)
72 73


74 75 76
activity_context = contextmanager(activitycontextimpl)


77 78 79
activity_code_separator = '.'


80 81 82
def has_prefix(activity_code, *prefixes):
    """Determine whether the activity code has the specified prefix.

83 84 85 86 87
    >>> assert has_prefix('foo.bar.buz', 'foo.bar')
    >>> assert has_prefix('foo.bar.buz', 'foo', 'bar')
    >>> assert has_prefix('foo.bar.buz', 'foo.bar', 'buz')
    >>> assert has_prefix('foo.bar.buz', 'foo', 'bar', 'buz')
    >>> assert not has_prefix('foo.bar.buz', 'foo', 'buz')
88 89 90 91 92 93 94 95 96 97
    """
    equal = lambda a, b: a == b
    act_code_parts = split_activity_code(activity_code)
    prefixes = chain(*imap(split_activity_code, prefixes))
    return all(imap(equal, act_code_parts, prefixes))


def has_suffix(activity_code, *suffixes):
    """Determine whether the activity code has the specified suffix.

98 99 100 101 102
    >>> assert has_suffix('foo.bar.buz', 'bar.buz')
    >>> assert has_suffix('foo.bar.buz', 'bar', 'buz')
    >>> assert has_suffix('foo.bar.buz', 'foo.bar', 'buz')
    >>> assert has_suffix('foo.bar.buz', 'foo', 'bar', 'buz')
    >>> assert not has_suffix('foo.bar.buz', 'foo', 'buz')
103 104 105
    """
    equal = lambda a, b: a == b
    act_code_parts = split_activity_code(activity_code)
106
    suffixes = list(chain(*imap(split_activity_code, suffixes)))
107 108 109
    return all(imap(equal, reversed(act_code_parts), reversed(suffixes)))


110 111
def join_activity_code(*args):
    """Join the specified parts into an activity code.
112 113

    :returns: Activity code string.
114 115 116 117
    """
    return activity_code_separator.join(args)


118 119 120 121 122 123 124 125
def split_activity_code(activity_code):
    """Split the specified activity code into its parts.

    :returns: A list of activity code parts.
    """
    return activity_code.split(activity_code_separator)


126 127 128 129 130 131 132 133 134 135
class Encoder(DjangoJSONEncoder):
    def default(self, obj):
        if isinstance(obj, Promise):
            obj = force_text(obj)
        try:
            return super(Encoder, self).default(obj)
        except TypeError:
            return unicode(obj)


136 137
class ActivityModel(TimeStampedModel):
    activity_code = CharField(max_length=100, verbose_name=_('activity code'))
138
    readable_name_data = JSONField(blank=True, null=True,
139
                                   dump_kwargs={"cls": Encoder},
140 141 142
                                   verbose_name=_('human readable name'),
                                   help_text=_('Human readable name of '
                                               'activity.'))
143
    parent = ForeignKey('self', blank=True, null=True, related_name='children')
144 145 146 147 148 149 150 151 152 153 154
    task_uuid = CharField(blank=True, max_length=50, null=True, unique=True,
                          help_text=_('Celery task unique identifier.'),
                          verbose_name=_('task_uuid'))
    user = ForeignKey(User, blank=True, null=True, verbose_name=_('user'),
                      help_text=_('The person who started this activity.'))
    started = DateTimeField(verbose_name=_('started at'),
                            blank=True, null=True,
                            help_text=_('Time of activity initiation.'))
    finished = DateTimeField(verbose_name=_('finished at'),
                             blank=True, null=True,
                             help_text=_('Time of activity finalization.'))
155 156 157
    succeeded = NullBooleanField(blank=True, null=True,
                                 help_text=_('True, if the activity has '
                                             'finished successfully.'))
158
    result_data = JSONField(verbose_name=_('result'), blank=True, null=True,
159
                            dump_kwargs={"cls": Encoder},
160
                            help_text=_('Human readable result of activity.'))
161

162 163 164 165 166 167
    def __unicode__(self):
        if self.parent:
            return self.parent.activity_code + "->" + self.activity_code
        else:
            return self.activity_code

168 169 170
    class Meta:
        abstract = True

171
    def finish(self, succeeded, result=None, event_handler=None):
172 173
        if not self.finished:
            self.finished = timezone.now()
174
            self.succeeded = succeeded
175 176
            if result is not None:
                self.result = result
177 178
            if event_handler is not None:
                event_handler(self)
179
            self.save()
180

181 182 183 184 185 186 187 188
    @property
    def has_succeeded(self):
        return self.finished and self.succeeded

    @property
    def has_failed(self):
        return self.finished and not self.succeeded

189
    @property
190 191 192 193
    def readable_name(self):
        return HumanReadableObject.from_dict(self.readable_name_data)

    @readable_name.setter
Dudás Ádám committed
194
    def readable_name(self, value):
195 196 197
        self.readable_name_data = None if value is None else value.to_dict()

    @property
198 199 200 201
    def result(self):
        return HumanReadableObject.from_dict(self.result_data)

    @result.setter
Dudás Ádám committed
202
    def result(self, value):
203 204
        if isinstance(value, basestring):
            warn("Using string as result value is deprecated. Use "
205 206
                 "HumanReadableObject instead.",
                 DeprecationWarning, stacklevel=2)
207 208
            value = create_readable(user_text_template="",
                                    admin_text_template=value)
209 210 211 212
        elif not hasattr(value, "to_dict"):
            warn("Use HumanReadableObject.", DeprecationWarning, stacklevel=2)
            value = create_readable(user_text_template="",
                                    admin_text_template=unicode(value))
213

214 215
        self.result_data = None if value is None else value.to_dict()

216

217 218 219 220 221 222 223
@celery.task()
def compute_cached(method, instance, memcached_seconds,
                   key, start, *args, **kwargs):
    """Compute and store actual value of cached method."""
    if isinstance(method, basestring):
        model, id = instance
        instance = model.objects.get(id=id)
224
        try:
225
            method = getattr(model, method)
226 227 228 229 230
            while hasattr(method, '_original') or hasattr(method, 'fget'):
                try:
                    method = method._original
                except AttributeError:
                    method = method.fget
231 232 233 234 235
        except AttributeError:
            logger.exception("Couldnt get original method of %s.%s",
                             unicode(instance), method.__name__)
            raise

236 237 238 239 240 241 242 243 244 245 246 247 248
    #  call the actual method
    result = method(instance, *args, **kwargs)
    # save to memcache
    cache.set(key, result, memcached_seconds)
    elapsed = time() - start
    cache.set("%s.cached" % key, 2, max(memcached_seconds * 0.5,
                                        memcached_seconds * 0.75 - elapsed))
    logger.debug('Value of <%s>.%s(%s)=<%s> saved to cache (%s elapsed).',
                 unicode(instance), method.__name__, unicode(args),
                 unicode(result), elapsed)
    return result


249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269
def method_cache(memcached_seconds=60, instance_seconds=5):  # noqa
    """Cache return value of decorated method to memcached and memory.

    :param memcached_seconds: Invalidate memcached results after this time.
    :param instance_seconds: Invalidate results cached to static memory after
    this time.

    If a result is cached on instance, return that first.  If that fails, check
    memcached. If all else fails, run the method and cache on instance and in
    memcached.

    Do not use for methods with side effects.
    Instances are hashed by their id attribute, args by their unicode
    representation.

    ** NOTE: Methods that return None are always "recached".
    Based on https://djangosnippets.org/snippets/2477/
    """

    def inner_cache(method):

270 271
        method_name = method.__name__

272 273
        def get_key(instance, *args, **kwargs):
            return sha224(unicode(method.__module__) +
274
                          method_name +
275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292
                          unicode(instance.id) +
                          unicode(args) +
                          unicode(kwargs)).hexdigest()

        def x(instance, *args, **kwargs):
            invalidate = kwargs.pop('invalidate_cache', False)
            now = time()
            key = get_key(instance, *args, **kwargs)

            result = None
            try:
                vals = getattr(instance, key)
            except AttributeError:
                pass
            else:
                if vals['time'] + instance_seconds > now:
                    # has valid on class cache, return that
                    result = vals['value']
293
                    setattr(instance, key, {'time': now, 'value': result})
294 295 296 297 298

            if result is None:
                result = cache.get(key)

            if invalidate or (result is None):
299 300 301
                logger.debug("all caches failed, compute now")
                result = compute_cached(method, instance, memcached_seconds,
                                        key, time(), *args, **kwargs)
302
                setattr(instance, key, {'time': now, 'value': result})
303 304 305
            elif not cache.get("%s.cached" % key):
                logger.debug("caches expiring, compute async")
                cache.set("%s.cached" % key, 1, memcached_seconds * 0.5)
306 307 308 309 310 311 312
                try:
                    compute_cached.apply_async(
                        queue='localhost.man', kwargs=kwargs, args=[
                            method_name, (instance.__class__, instance.id),
                            memcached_seconds, key, time()] + list(args))
                except:
                    logger.exception("Couldnt compute async %s", method_name)
313 314

            return result
315 316 317

        update_wrapper(x, method)
        x._original = method
318 319 320
        return x

    return inner_cache
Őry Máté committed
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


class HumanSortField(CharField):
    """
    A CharField that monitors another field on the same model and sets itself
    to a normalized value, which can be used for sensible lexicographycal
    sorting for fields containing numerals. (Avoiding technically correct
    orderings like [a1, a10, a2], which can be annoying for file or host
    names.)

    Apart from CharField's default arguments, an argument is requered:
        - monitor   sets the base field, whose value is normalized.
        - maximum_number_length    can also be provided, and defaults to 4. If
        you have to sort values containing numbers greater than 9999, you
        should increase it.

    Code is based on carljm's django-model-utils.
    """
    def __init__(self, *args, **kwargs):
        logger.debug('Initing HumanSortField(%s %s)',
                     unicode(args), unicode(kwargs))
        kwargs.setdefault('default', "")
        self.maximum_number_length = kwargs.pop('maximum_number_length', 4)
        monitor = kwargs.pop('monitor', None)
        if not monitor:
            raise TypeError(
                '%s requires a "monitor" argument' % self.__class__.__name__)
        self.monitor = monitor
        kwargs['blank'] = True
        super(HumanSortField, self).__init__(*args, **kwargs)

    def get_monitored_value(self, instance):
        return getattr(instance, self.monitor)

355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373
    @staticmethod
    def _partition(s, pred):
        """Partition a deque of chars to a tuple of a
           - string of the longest prefix matching pred,
           - string of the longest prefix after the former one not matching,
           - deque of the remaining characters.

           >>> HumanSortField._partition(deque("1234abc567"),
           ...                           lambda s: s.isdigit())
           ('1234', 'abc', deque(['5', '6', '7']))
           >>> HumanSortField._partition(deque("12ab"), lambda s: s.isalpha())
           ('', '12', deque(['a', 'b']))
        """
        match, notmatch = deque(), deque()
        while s and pred(s[0]):
            match.append(s.popleft())
        while s and not pred(s[0]):
            notmatch.append(s.popleft())
        return (''.join(match), ''.join(notmatch), s)
Őry Máté committed
374

375
    def get_normalized_value(self, val):
Őry Máté committed
376 377 378 379
        logger.debug('Normalizing value: %s', val)
        norm = ""
        val = deque(val)
        while val:
380 381 382 383
            numbers, letters, val = self._partition(val,
                                                    lambda s: s[0].isdigit())
            if numbers:
                norm += numbers.rjust(self.maximum_number_length, '0')
Őry Máté committed
384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408
            norm += letters
        logger.debug('Normalized value: %s', norm)
        return norm

    def pre_save(self, model_instance, add):
        logger.debug('Pre-saving %s.%s. %s',
                     model_instance, self.attname, add)
        value = self.get_normalized_value(
            self.get_monitored_value(model_instance))
        setattr(model_instance, self.attname, value[:self.max_length])
        return super(HumanSortField, self).pre_save(model_instance, add)

# allow South to handle these fields smoothly
try:
    from south.modelsinspector import add_introspection_rules
    add_introspection_rules(rules=[
        (
            (HumanSortField,),
            [],
            {'monitor': ('monitor', {}),
             'maximum_number_length': ('maximum_number_length', {}), }
        ),
    ], patterns=['common\.models\.'])
except ImportError:
    pass
409 410 411 412


class HumanReadableObject(object):
    def __init__(self, user_text_template, admin_text_template, params):
413 414 415
        self._set_values(user_text_template, admin_text_template, params)

    def _set_values(self, user_text_template, admin_text_template, params):
416 417 418 419 420
        self.user_text_template = user_text_template
        self.admin_text_template = admin_text_template
        self.params = params

    @classmethod
421
    def create(cls, user_text_template, admin_text_template=None, **params):
422 423 424
        return cls(user_text_template=user_text_template,
                   admin_text_template=(admin_text_template
                                        or user_text_template), params=params)
425

426 427 428 429
    def set(self, user_text_template, admin_text_template=None, **params):
        self._set_values(user_text_template,
                         admin_text_template or user_text_template, params)

430 431 432 433 434
    @classmethod
    def from_dict(cls, d):
        return None if d is None else cls(**d)

    def get_admin_text(self):
435 436
        if self.admin_text_template == "":
            return ""
437 438 439 440 441 442
        try:
            return _(self.admin_text_template) % self.params
        except KeyError:
            logger.exception("Can't render admin_text_template '%s' %% %s",
                             self.admin_text_template, unicode(self.params))
            return self.get_user_text()
443 444

    def get_user_text(self):
445 446
        if self.user_text_template == "":
            return ""
447 448 449 450 451 452
        try:
            return _(self.user_text_template) % self.params
        except KeyError:
            logger.exception("Can't render user_text_template '%s' %% %s",
                             self.user_text_template, unicode(self.params))
            return self.user_text_template
453 454 455 456 457 458

    def to_dict(self):
        return {"user_text_template": self.user_text_template,
                "admin_text_template": self.admin_text_template,
                "params": self.params}

459 460 461 462
    def __unicode__(self):
        return self.get_user_text()


463
create_readable = HumanReadableObject.create
464 465 466 467 468


class HumanReadableException(HumanReadableObject, Exception):
    """HumanReadableObject that is an Exception so can used in except clause.
    """
469

470 471 472 473 474 475 476 477 478 479 480 481 482 483
    def __init__(self, level=None, *args, **kwargs):
        super(HumanReadableException, self).__init__(*args, **kwargs)
        if level is not None:
            if hasattr(messages, level):
                self.level = level
            else:
                raise ValueError(
                    "Level should be the name of an attribute of django."
                    "contrib.messages (and it should be callable with "
                    "(request, message)). Like 'error', 'warning'.")
        else:
            self.level = "error"

    def send_message(self, request, level=None):
484 485 486 487
        if request.user and request.user.is_superuser:
            msg = self.get_admin_text()
        else:
            msg = self.get_user_text()
488
        getattr(messages, level or self.level)(request, msg)
489 490


491
def humanize_exception(message, exception=None, level=None, **params):
492 493 494 495 496 497 498 499 500 501 502 503
    """Return new dynamic-class exception which is based on
    HumanReadableException and the original class with the dict of exception.

    >>> try: raise humanize_exception("Welcome!", TypeError("hello"))
    ... except HumanReadableException as e: print e.get_admin_text()
    ...
    Welcome!
    """

    Ex = type("HumanReadable" + type(exception).__name__,
              (HumanReadableException, type(exception)),
              exception.__dict__)
504 505 506 507
    ex = Ex.create(message, **params)
    if level:
        ex.level = level
    return ex