42 lines
1.7 KiB
Python
42 lines
1.7 KiB
Python
# Copyright 2015 Hewlett-Packard Development Company, L.P.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from sqlalchemy.types import TypeDecorator, DateTime
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import pytz
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class UTCDateTime(TypeDecorator):
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"""This decorator ensures that timezones will always remain attached to
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datetime fields that are written to/from the database, since mysql does
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NOT support timezones in its datetime fields. In the case that a
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value is provided without a timezone, it will raise an exception to draw
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attention to itself: Engineers should always work with timezoned
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datetime instances.
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"""
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impl = DateTime
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def process_bind_param(self, value, engine):
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if value is not None:
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# If the value doesn't have a timezone, raise an exception.
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if not value.tzinfo:
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raise RuntimeError("Datetime value without timezone provided,"
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" please provide a timezone.")
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# Convert to UTC, then scrub the timezone for storing in MySQL.
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return value.astimezone(pytz.utc).replace(tzinfo=None)
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def process_result_value(self, value, engine):
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if value is not None:
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return value.replace(tzinfo=pytz.utc)
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