dc56ff482a
1. Simplify the exposed api to reduce race conditions which could occur if we allowed flow details, task details and log books to be deleted at different times; reduce this down to just being able to save and delete from logbooks (and only save/update for flow and task details to) to reduce the problem cases. 2. Introduce a alembic migration with a proper schema so that the initial database can be created in the first place, adjust its exposed fields and relations to be defined by said schema. 3. Use oslo db models instead of our own. Change-Id: I78bbedf87d506d3f39157198638937c933235b7b
63 lines
2.3 KiB
Python
63 lines
2.3 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2013 Rackspace Hosting Inc. All Rights Reserved.
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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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import threading
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from taskflow import exceptions as exc
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from taskflow.openstack.common import importutils
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_BACKEND_MAPPING = {
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'memory': 'taskflow.persistence.backends.memory.api',
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'sqlalchemy': 'taskflow.persistence.backends.sqlalchemy.api',
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# TODO(harlowja): we likely need to allow more customization here so that
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# its easier for a user of this library to alter the impl to there own
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# choicing, aka, cinder has its own DB, or heat may want to write this
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# information into swift, we need a way to accomodate that.
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}
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_BACKEND_MAPPING_LOCK = threading.RLock()
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_BACKENDS = {}
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_BACKEND_LOCK = threading.RLock()
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def register(backend, module):
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"""Register a new (or override an old) backend type.
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Instead of being restricted to the existing types that are pre-registered
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in taskflow it is useful to allow others to either override those types
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or add new ones (since all backend types can not be predicted ahead of
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time).
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"""
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with _BACKEND_MAPPING_LOCK:
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_BACKEND_MAPPING[backend] = str(module)
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def fetch(backend):
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"""Fetch a backend impl. for a given backend type."""
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with _BACKEND_MAPPING_LOCK:
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if backend not in _BACKEND_MAPPING:
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raise exc.NotFound("Unknown backend %s requested" % (backend))
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mod = _BACKEND_MAPPING.get(backend, backend)
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with _BACKEND_LOCK:
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if mod in _BACKENDS:
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return _BACKENDS[mod]
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backend_mod = importutils.import_module(mod)
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backend_impl = backend_mod.get_backend()
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_BACKENDS[mod] = backend_impl
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return backend_impl
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