58 lines
1.9 KiB
Python
58 lines
1.9 KiB
Python
# Copyright (c) 2014 Mirantis, Inc.
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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 alembic import op
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import six
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import sqlalchemy as sa
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def transform_table(name, renames, defaults, *columns, **kw):
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def escape(val):
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if isinstance(val, six.string_types):
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return "'{0}'".format(val)
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elif val is None:
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return 'NULL'
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else:
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return val
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engine = op.get_bind()
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meta = sa.MetaData(bind=engine)
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meta.reflect()
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new_name = name + '__tmp'
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old_table = meta.tables[name]
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mapping = dict(
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(renames.get(col.name, col.name), col.name) for col in old_table.c
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)
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columns_to_select = [
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old_table.c[mapping[c.name]]
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if c.name in mapping else escape(defaults.get(c.name))
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for c in columns if isinstance(c, sa.Column)
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]
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select_as = [
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c.name for c in columns if isinstance(c, sa.Column)
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]
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select = sa.sql.select(columns_to_select)
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op.create_table(new_name, *columns, **kw)
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meta.reflect()
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new_table = meta.tables[new_name]
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insert = sa.sql.insert(new_table)
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if engine.dialect.dialect_description == 'postgresql+psycopg2':
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insert = insert.returning(next(iter(new_table.primary_key.columns)))
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insert = insert.from_select(select_as, select)
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engine.execute(insert)
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op.drop_table(name)
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op.rename_table(new_name, name)
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