65 lines
1.8 KiB
Go
65 lines
1.8 KiB
Go
// Copyright (c) 2015 Arista Networks, Inc.
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// Use of this source code is governed by the Apache License 2.0
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// that can be found in the COPYING file.
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package monitor
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import (
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"expvar"
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"strings"
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"time"
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"github.com/aristanetworks/goarista/monitor/stats"
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)
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// LatencyHistogram contains the data needed to properly export itself to expvar
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// and provide a pretty printed version
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type LatencyHistogram struct {
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name string
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histogram *stats.Histogram
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latencyUnit time.Duration
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}
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// NewLatencyHistogram creates a new histogram and registers an HTTP handler for it.
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func NewLatencyHistogram(name string, latencyUnit time.Duration, numBuckets int,
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growth float64, smallest float64, minValue int64) *LatencyHistogram {
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histogramOptions := stats.HistogramOptions{
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NumBuckets: numBuckets,
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GrowthFactor: growth,
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SmallestBucketSize: smallest,
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MinValue: minValue,
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}
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histogram := &LatencyHistogram{
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name: name,
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histogram: stats.NewHistogram(histogramOptions),
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latencyUnit: latencyUnit,
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}
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expvar.Publish(name, histogram)
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return histogram
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}
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// Print returns the histogram as a chart
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func (h *LatencyHistogram) Print() string {
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return h.addUnits(h.histogram.Delta1m().String()) +
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h.addUnits(h.histogram.Delta10m().String()) +
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h.addUnits(h.histogram.Delta1h().String()) +
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h.addUnits(h.histogram.Value().String())
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}
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// String returns the histogram as JSON.
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func (h *LatencyHistogram) String() string {
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return h.histogram.String()
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}
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// UpdateLatencyValues updates the LatencyHistogram's buckets with the new
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// datapoint and updates the string associated with the expvar.String
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func (h *LatencyHistogram) UpdateLatencyValues(delta time.Duration) {
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h.histogram.Add(int64(delta / h.latencyUnit))
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}
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func (h *LatencyHistogram) addUnits(hist string) string {
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i := strings.Index(hist, "\n")
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return hist[:i] + "µs" + hist[i:]
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}
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