5269daad88
Add database APIs for a conductor to lock/steal/release a bay. There will be more than one conductors, so it is necessary to implement a distributed locking APIs to prevent race conditions. * Lock acquisition: A conductor should acquire a lock when it is about to perform an operation on a bay (e.g. create/update/delete a bay). The conductor should check the return value of the APIs to determine if the lock is successfully acquired. If yes, another conductor that attempts to lock the same bay will not succeed. Upon completion, the conductor should release the acquired lock to allow other conductors to operate the bay later. * Lock stealing: If conductor A acquires a lock and crashes unexpectedly, conductor B can steal the lock acquired by conductor A. To do that, conductor B needs to give the id of conductor A along with other parameters. The lock stealing will succeed if the bay is indeed locked by conductor A at the moment of the stealing requests. Change-Id: I95f28361eea361d878d2c047937c3beef4fb445a Partial-Implements: blueprint horizontal-scale
41 lines
1.3 KiB
Python
41 lines
1.3 KiB
Python
# 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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"""create baylock table
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Revision ID: 456126c6c9e9
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Revises: 2ace4006498
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Create Date: 2015-04-01 15:04:45.652672
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"""
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# revision identifiers, used by Alembic.
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revision = '456126c6c9e9'
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down_revision = '2ace4006498'
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from alembic import op
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import sqlalchemy as sa
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def upgrade():
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op.create_table(
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'baylock',
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sa.Column('created_at', sa.DateTime(), nullable=True),
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sa.Column('updated_at', sa.DateTime(), nullable=True),
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sa.Column('id', sa.Integer(), nullable=False),
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sa.Column('bay_uuid', sa.String(length=36), nullable=True),
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sa.Column('conductor_id', sa.String(length=64), nullable=True),
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sa.PrimaryKeyConstraint('id'),
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mysql_ENGINE='InnoDB',
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mysql_DEFAULT_CHARSET='UTF8'
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)
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