cd503ba499
Fix typo in Valence Change-Id: Ib0666ad381d2332aa7e0f1a7e9d3dca0e6207a5c Signed-off-by: Andy Yan <yanchao3@lenovo.com>
93 lines
2.5 KiB
ReStructuredText
93 lines
2.5 KiB
ReStructuredText
.. _valence_db_development:
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Copyright 2016 Intel Corporation
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All Rights Reserved.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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==============
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DB Development
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==============
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Valence uses Etcd as the management DB for handling multiple pod managers,
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as well as underneath hardware resources info.
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There is one root Etcd directory for the pod managers, named
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"/pod_managers".
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Each key-value pair under directory "/pod_managers" indicates
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information about one pod manager.
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.. NOTE::
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All db layer codes are located in valence/db.
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Add a model for db
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------------------
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Models are defined in the valence/db/models.py file. A new model
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should be updated there.
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To add an example model for Etcd db, we should create
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a class that inherits the ModelBase class in valence/db/models.py.
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.. NOTE::
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If timestamp info is needed for this model,
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please inherit ModelBaseWithTimestamp class instead.
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i.e.
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.. code-block:: python
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# valence/db/models.py
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class ExampleModel(ModelBase):
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# This is the Etcd dir the new model lives in
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path = "example_model"
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# The fields will be wrapped as a value for one object
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fields = {
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'uuid': {
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'validate': types.Text.validate
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},
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'name': {
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'validate': types.Text.validate
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},
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}
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Add a driver for model
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----------------------
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Etcd driver definition is in the file valence/db/etcd_driver.py.
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Considering adding operations for one example model,
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we should create a class in valence/db/etcd_driver.py.
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i.e.
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.. code-block:: python
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# valence/db/etcd_driver.py
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@six.add_metaclass(singleton.Singleton)
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class ExampleDriver(object):
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def __init__(self, host=config.etcd_host, port=config.etcd_port):
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self.client = etcd.Client(host=host, port=port)
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def get_example_object(self, object_id):
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pass
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def create_example_object(self, values):
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pass
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There should be more guides to be continued later.
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