46 lines
1.9 KiB
Python
46 lines
1.9 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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def needs_update(targ_capacity, curr_capacity, num_up_to_date):
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"""Return whether there are more batch updates to do.
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Inputs are the target size for the group, the current size of the group,
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and the number of members that already have the latest definition.
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"""
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return not (num_up_to_date >= curr_capacity == targ_capacity)
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def next_batch(targ_capacity, curr_capacity, num_up_to_date, batch_size,
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min_in_service):
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"""Return details of the next batch in a batched update.
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The result is a tuple containing the new size of the group and the number
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of members that may receive the new definition (by a combination of
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creating new members and updating existing ones).
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Inputs are the target size for the group, the current size of the group,
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the number of members that already have the latest definition, the batch
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size, and the minimum number of members to keep in service during a rolling
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update.
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"""
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assert num_up_to_date <= curr_capacity
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efft_min_sz = min(min_in_service, targ_capacity, curr_capacity)
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efft_bat_sz = min(batch_size, max(targ_capacity - num_up_to_date, 0))
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new_capacity = efft_bat_sz + max(min(curr_capacity,
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targ_capacity - efft_bat_sz),
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efft_min_sz)
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return new_capacity, efft_bat_sz
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