81b45f2c1d
The statless design was developed in the experiment branch, the experiment shows advantage in removing the status synchronization, uuid mapping compared to the stateful design, and also fully reduce the coupling with OpenStack services like Nova, Cinder. The overhead query latency for resources also acceptable. It's time to move the statless design to the master branch BP: https://blueprints.launchpad.net/tricircle/+spec/implement-stateless Change-Id: I51bbb60dc07da5b2e79f25e02209aa2eb72711ac Signed-off-by: Chaoyi Huang <joehuang@huawei.com>
125 lines
5.1 KiB
Python
125 lines
5.1 KiB
Python
# Copyright 2015 Huawei Technologies Co., Ltd.
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# 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 datetime
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import eventlet
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import oslo_db.exception as db_exc
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from tricircle.db import core
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from tricircle.db import models
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def get_or_create_route(t_ctx, q_ctx,
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project_id, pod, _id, _type, list_ele_method):
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# use configuration option later
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route_expire_threshold = 30
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with t_ctx.session.begin():
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routes = core.query_resource(
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t_ctx, models.ResourceRouting,
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[{'key': 'top_id', 'comparator': 'eq', 'value': _id},
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{'key': 'pod_id', 'comparator': 'eq',
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'value': pod['pod_id']}], [])
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if routes:
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route = routes[0]
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if route['bottom_id']:
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return route, False
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else:
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route_time = route['updated_at'] or route['created_at']
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current_time = datetime.datetime.utcnow()
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delta = current_time - route_time
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if delta.seconds > route_expire_threshold:
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# NOTE(zhiyuan) cannot directly remove the route, we have
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# a race here that other worker is updating this route, we
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# need to check if the corresponding element has been
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# created by other worker
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eles = list_ele_method(t_ctx, q_ctx, pod, _id, _type)
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if eles:
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route['bottom_id'] = eles[0]['id']
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core.update_resource(t_ctx,
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models.ResourceRouting,
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route['id'], route)
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return route, False
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try:
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core.delete_resource(t_ctx,
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models.ResourceRouting,
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route['id'])
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except db_exc.ResourceNotFound:
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pass
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try:
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# NOTE(zhiyuan) try/except block inside a with block will cause
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# problem, so move them out of the block and manually handle the
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# session context
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t_ctx.session.begin()
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route = core.create_resource(t_ctx, models.ResourceRouting,
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{'top_id': _id,
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'pod_id': pod['pod_id'],
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'project_id': project_id,
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'resource_type': _type})
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t_ctx.session.commit()
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return route, True
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except db_exc.DBDuplicateEntry:
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t_ctx.session.rollback()
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return None, False
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finally:
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t_ctx.session.close()
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def get_or_create_element(t_ctx, q_ctx,
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project_id, pod, ele, _type, body,
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list_ele_method, create_ele_method):
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# use configuration option later
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max_tries = 5
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for _ in xrange(max_tries):
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route, is_new = get_or_create_route(
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t_ctx, q_ctx, project_id, pod, ele['id'], _type, list_ele_method)
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if not route:
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eventlet.sleep(0)
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continue
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if not is_new and not route['bottom_id']:
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eventlet.sleep(0)
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continue
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if not is_new and route['bottom_id']:
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break
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if is_new:
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try:
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ele = create_ele_method(t_ctx, q_ctx, pod, body, _type)
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except Exception:
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with t_ctx.session.begin():
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try:
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core.delete_resource(t_ctx,
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models.ResourceRouting,
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route['id'])
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except db_exc.ResourceNotFound:
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# NOTE(zhiyuan) this is a rare case that other worker
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# considers the route expires and delete it though it
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# was just created, maybe caused by out-of-sync time
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pass
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raise
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with t_ctx.session.begin():
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# NOTE(zhiyuan) it's safe to update route, the bottom network
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# has been successfully created, so other worker will not
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# delete this route
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route['bottom_id'] = ele['id']
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core.update_resource(t_ctx, models.ResourceRouting,
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route['id'], route)
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break
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if not route:
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raise Exception('Fail to create %s routing entry' % _type)
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if not route['bottom_id']:
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raise Exception('Fail to bind top and bottom %s' % _type)
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return is_new, route['bottom_id']
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