Source code for google.appengine.api.croninfo

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#




"""CronInfo tools.

A library for working with CronInfo records, describing cron entries for an
application. Supports loading the records from yaml.
"""








import logging
import os
import sys
import traceback

try:
  import pytz
except ImportError:
  pytz = None

from google.appengine.cron import groc
from google.appengine.cron import groctimespecification


if os.environ.get('APPENGINE_RUNTIME') == 'python27':
  from google.appengine.api import appinfo
  from google.appengine.api import validation
  from google.appengine.api import yaml_builder
  from google.appengine.api import yaml_listener
  from google.appengine.api import yaml_object
else:
  from google.appengine.api import appinfo
  from google.appengine.api import validation
  from google.appengine.api import yaml_builder
  from google.appengine.api import yaml_listener
  from google.appengine.api import yaml_object


_URL_REGEX = r'^/.*$'
_TIMEZONE_REGEX = r'^.{0,100}$'
_DESCRIPTION_REGEX = ur'^.{0,499}$'


SERVER_ID_RE_STRING = r'(?!-)[a-z\d\-]{1,63}'


SERVER_VERSION_RE_STRING = r'(?!-)[a-z\d\-]{1,100}'
_VERSION_REGEX = r'^(?:(?:(%s):)?)(%s)$' % (SERVER_ID_RE_STRING,
                                            SERVER_VERSION_RE_STRING)




[docs]class GrocValidator(validation.Validator): """Checks that a schedule is in valid groc format."""
[docs] def Validate(self, value, key=None): """Validates a schedule.""" if value is None: raise validation.MissingAttribute('schedule must be specified') if not isinstance(value, basestring): raise TypeError('schedule must be a string, not \'%r\''%type(value)) try: groctimespecification.GrocTimeSpecification(value) except groc.GrocException, e: raise validation.ValidationError('schedule \'%s\' failed to parse: %s'%( value, e.args[0])) return value
[docs]class TimezoneValidator(validation.Validator): """Checks that a timezone can be correctly parsed and is known."""
[docs] def Validate(self, value, key=None): """Validates a timezone.""" if value is None: return if not isinstance(value, basestring): raise TypeError('timezone must be a string, not \'%r\'' % type(value)) if pytz is None: return value try: pytz.timezone(value) except pytz.UnknownTimeZoneError: raise validation.ValidationError('timezone \'%s\' is unknown' % value) except IOError: return value except: unused_e, v, t = sys.exc_info() logging.warning('pytz raised an unexpected error: %s.\n' % (v) + 'Traceback:\n' + '\n'.join(traceback.format_tb(t))) raise return value
CRON = 'cron' URL = 'url' SCHEDULE = 'schedule' TIMEZONE = 'timezone' DESCRIPTION = 'description' TARGET = 'target' RETRY_PARAMETERS = 'retry_parameters' JOB_RETRY_LIMIT = 'job_retry_limit' JOB_AGE_LIMIT = 'job_age_limit' MIN_BACKOFF_SECONDS = 'min_backoff_seconds' MAX_BACKOFF_SECONDS = 'max_backoff_seconds' MAX_DOUBLINGS = 'max_doublings'
[docs]class MalformedCronfigurationFile(Exception): """Configuration file for Cron is malformed.""" pass
[docs]class RetryParameters(validation.Validated): """Retry parameters for a single cron job.""" ATTRIBUTES = { JOB_RETRY_LIMIT: validation.Optional( validation.Range(0, None, range_type=int)), JOB_AGE_LIMIT: validation.Optional(validation.TimeValue()), MIN_BACKOFF_SECONDS: validation.Optional( validation.Range(0.0, None, range_type=float)), MAX_BACKOFF_SECONDS: validation.Optional( validation.Range(0.0, None, range_type=float)), MAX_DOUBLINGS: validation.Optional( validation.Range(0, None, range_type=int)), }
[docs]class CronEntry(validation.Validated): """A cron entry describes a single cron job.""" ATTRIBUTES = { URL: _URL_REGEX, SCHEDULE: GrocValidator(), TIMEZONE: TimezoneValidator(), DESCRIPTION: validation.Optional(_DESCRIPTION_REGEX), RETRY_PARAMETERS: validation.Optional(RetryParameters), TARGET: validation.Optional(_VERSION_REGEX), }
[docs]class CronInfoExternal(validation.Validated): """CronInfoExternal describes all cron entries for an application.""" ATTRIBUTES = { appinfo.APPLICATION: validation.Optional(appinfo.APPLICATION_RE_STRING), CRON: validation.Optional(validation.Repeated(CronEntry)) }
[docs]def LoadSingleCron(cron_info, open_fn=None): """Load a cron.yaml file or string and return a CronInfoExternal object.""" builder = yaml_object.ObjectBuilder(CronInfoExternal) handler = yaml_builder.BuilderHandler(builder) listener = yaml_listener.EventListener(handler) listener.Parse(cron_info) cron_info_result = handler.GetResults() if len(cron_info_result) < 1: raise MalformedCronfigurationFile('Empty cron configuration.') if len(cron_info_result) > 1: raise MalformedCronfigurationFile('Multiple cron sections ' 'in configuration.') return cron_info_result[0]

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