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58 lines
1.3 KiB
58 lines
1.3 KiB
6 years ago
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package metric
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import "sync"
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// PointPolicy is a policy of points within the window.
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// PointPolicy wraps the window and make it seem like ring-buf.
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// When using PointPolicy, every buckets within the windows contains at more one point.
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// e.g. [[1], [2], [3]]
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type PointPolicy struct {
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mu sync.RWMutex
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size int
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window *Window
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offset int
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}
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// NewPointPolicy creates a new PointPolicy.
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func NewPointPolicy(window *Window) *PointPolicy {
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return &PointPolicy{
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window: window,
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size: window.Size(),
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offset: -1,
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}
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}
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func (p *PointPolicy) prevOffset() int {
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return p.offset
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}
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func (p *PointPolicy) nextOffset() int {
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return (p.prevOffset() + 1) % p.size
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}
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func (p *PointPolicy) updateOffset(offset int) {
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p.offset = offset
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}
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// Append appends the given points to the window.
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func (p *PointPolicy) Append(val float64) {
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p.mu.Lock()
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defer p.mu.Unlock()
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offset := p.nextOffset()
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p.window.ResetBucket(offset)
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p.window.Append(offset, val)
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p.updateOffset(offset)
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}
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// Reduce applies the reduction function to all buckets within the window.
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func (p *PointPolicy) Reduce(f func(Iterator) float64) float64 {
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p.mu.RLock()
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defer p.mu.RUnlock()
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offset := p.offset + 1
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if offset == p.size {
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offset = 0
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}
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iterator := p.window.Iterator(offset, p.size)
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return f(iterator)
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}
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