mirror of
https://github.com/kubernetes-sigs/descheduler.git
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95a631f6a5
move the classifier to its own package. introduces a generic way of classifying usages against thresholds.
85 lines
3.1 KiB
Go
85 lines
3.1 KiB
Go
/*
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Copyright 2025 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain 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,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package classifier
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// Classifier is a function that classifies a resource usage based on a limit.
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// The function should return true if the resource usage matches the classifier
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// intent.
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type Classifier[K comparable, V any] func(K, V, V) bool
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// Comparer is a function that compares two objects. This function should return
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// -1 if the first object is less than the second, 0 if they are equal, and 1 if
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// the first object is greater than the second. Of course this is a simplification
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// and any value between -1 and 1 can be returned.
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type Comparer[V any] func(V, V) int
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// Values is a map of values indexed by a comparable key. An example of this
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// can be a list of resources indexed by a node name.
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type Values[K comparable, V any] map[K]V
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// Limits is a map of list of limits indexed by a comparable key. Each limit
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// inside the list requires a classifier to evaluate.
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type Limits[K comparable, V any] map[K][]V
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// Classify is a function that classifies based on classifier functions. This
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// function receives Values, a list of n Limits (indexed by name), and a list
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// of n Classifiers. The classifier at n position is called to evaluate the
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// limit at n position. The first classifier to return true will receive the
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// value, at this point the loop will break and the next value will be
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// evaluated. This function returns a slice of maps, each position in the
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// returned slice correspond to one of the classifiers (e.g. if n limits
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// and classifiers are provided, the returned slice will have n maps).
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func Classify[K comparable, V any](
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values Values[K, V], limits Limits[K, V], classifiers ...Classifier[K, V],
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) []map[K]V {
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result := make([]map[K]V, len(classifiers))
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for i := range classifiers {
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result[i] = make(map[K]V)
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}
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for index, usage := range values {
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for i, limit := range limits[index] {
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if len(classifiers) <= i {
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continue
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}
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if !classifiers[i](index, usage, limit) {
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continue
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}
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result[i][index] = usage
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break
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}
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}
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return result
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}
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// ForMap is a function that returns a classifier that compares all values in a
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// map. The function receives a Comparer function that is used to compare all
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// the map values. The returned Classifier will return true only if the
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// provided Comparer function returns a value less than 0 for all the values.
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func ForMap[K, I comparable, V any, M ~map[I]V](cmp Comparer[V]) Classifier[K, M] {
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return func(_ K, usages, limits M) bool {
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for idx, usage := range usages {
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if limit, ok := limits[idx]; ok {
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if cmp(usage, limit) >= 0 {
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return false
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}
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}
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}
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return true
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}
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}
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