59 lines
1.3 KiB
Go
59 lines
1.3 KiB
Go
/*
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Copyright (c) 2012, Matt T. Proud
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All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file.
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*/
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package metrics
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import (
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"container/heap"
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"github.com/prometheus/client_golang/maths"
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"github.com/prometheus/client_golang/utility"
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"time"
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)
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/*
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EvictionPolicy implements some sort of garbage collection methodology for
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an underlying heap.Interface. This is presently only used for
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AccumulatingBucket.
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*/
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type EvictionPolicy func(h heap.Interface)
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/*
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As the name implies, this evicts the oldest x objects from the heap.
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*/
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func EvictOldest(count int) EvictionPolicy {
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return func(h heap.Interface) {
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for i := 0; i < count; i++ {
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heap.Pop(h)
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}
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}
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}
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/*
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This factory produces an EvictionPolicy that applies some standardized
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reduction methodology on the to-be-terminated values.
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*/
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func EvictAndReplaceWith(count int, reducer maths.ReductionMethod) EvictionPolicy {
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return func(h heap.Interface) {
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oldValues := make([]float64, count)
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for i := 0; i < count; i++ {
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oldValues[i] = heap.Pop(h).(*utility.Item).Value.(float64)
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}
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reduced := reducer(oldValues)
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heap.Push(h, &utility.Item{
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Value: reduced,
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/*
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TODO(mtp): Parameterize the priority generation since these tools are useful.
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*/
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Priority: -1 * time.Now().UnixNano(),
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})
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}
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}
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