95 lines
2.8 KiB
Python
95 lines
2.8 KiB
Python
# Copyright 2017 Catalyst IT Limited
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# This module implements SQLAlchemy-based types for dict and list
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# expressed by json-strings
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#
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from oslo_serialization import jsonutils
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import sqlalchemy as sa
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from sqlalchemy.dialects import mysql
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from sqlalchemy.ext import mutable
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class JsonEncoded(sa.TypeDecorator):
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"""Represents an immutable structure as a json-encoded string."""
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impl = sa.Text
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def process_bind_param(self, value, dialect):
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if value is not None:
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value = jsonutils.dumps(value)
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return value
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def process_result_value(self, value, dialect):
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if value is not None:
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value = jsonutils.loads(value)
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return value
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class MutableList(mutable.Mutable, list):
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@classmethod
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def coerce(cls, key, value):
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"""Convert plain lists to MutableList."""
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if not isinstance(value, MutableList):
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if isinstance(value, list):
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return MutableList(value)
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# this call will raise ValueError
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return mutable.Mutable.coerce(key, value)
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return value
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def __add__(self, value):
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"""Detect list add events and emit change events."""
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list.__add__(self, value)
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self.changed()
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def append(self, value):
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"""Detect list add events and emit change events."""
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list.append(self, value)
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self.changed()
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def __setitem__(self, key, value):
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"""Detect list set events and emit change events."""
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list.__setitem__(self, key, value)
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self.changed()
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def __delitem__(self, i):
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"""Detect list del events and emit change events."""
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list.__delitem__(self, i)
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self.changed()
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def JsonDictType():
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"""Returns an SQLAlchemy Column Type suitable to store a Json dict."""
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return mutable.MutableDict.as_mutable(JsonEncoded)
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def JsonListType():
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"""Returns an SQLAlchemy Column Type suitable to store a Json array."""
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return MutableList.as_mutable(JsonEncoded)
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def LongText():
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# TODO(rakhmerov): Need to do for postgres.
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return sa.Text().with_variant(mysql.LONGTEXT(), 'mysql')
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class JsonEncodedLongText(JsonEncoded):
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impl = LongText()
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def JsonLongDictType():
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return mutable.MutableDict.as_mutable(JsonEncodedLongText)
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