156 lines
3.2 KiB
Go
156 lines
3.2 KiB
Go
package basicstats
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import (
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"math"
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"github.com/influxdata/telegraf"
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"github.com/influxdata/telegraf/plugins/aggregators"
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)
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type BasicStats struct {
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cache map[uint64]aggregate
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}
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func NewBasicStats() telegraf.Aggregator {
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mm := &BasicStats{}
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mm.Reset()
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return mm
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}
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type aggregate struct {
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fields map[string]basicstats
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name string
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tags map[string]string
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}
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type basicstats struct {
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count float64
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min float64
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max float64
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mean float64
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M2 float64 //intermedia value for variance/stdev
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}
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var sampleConfig = `
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## General Aggregator Arguments:
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## The period on which to flush & clear the aggregator.
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period = "30s"
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## If true, the original metric will be dropped by the
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## aggregator and will not get sent to the output plugins.
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drop_original = false
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`
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func (m *BasicStats) SampleConfig() string {
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return sampleConfig
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}
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func (m *BasicStats) Description() string {
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return "Keep the aggregate basicstats of each metric passing through."
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}
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func (m *BasicStats) Add(in telegraf.Metric) {
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id := in.HashID()
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if _, ok := m.cache[id]; !ok {
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// hit an uncached metric, create caches for first time:
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a := aggregate{
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name: in.Name(),
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tags: in.Tags(),
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fields: make(map[string]basicstats),
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}
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for k, v := range in.Fields() {
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if fv, ok := convert(v); ok {
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a.fields[k] = basicstats{
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count: 1,
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min: fv,
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max: fv,
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mean: fv,
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M2: 0.0,
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}
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}
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}
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m.cache[id] = a
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} else {
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for k, v := range in.Fields() {
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if fv, ok := convert(v); ok {
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if _, ok := m.cache[id].fields[k]; !ok {
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// hit an uncached field of a cached metric
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m.cache[id].fields[k] = basicstats{
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count: 1,
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min: fv,
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max: fv,
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mean: fv,
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M2: 0.0,
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}
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continue
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}
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tmp := m.cache[id].fields[k]
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//https://en.m.wikipedia.org/wiki/Algorithms_for_calculating_variance
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//variable initialization
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x := fv
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mean := tmp.mean
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M2 := tmp.M2
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//counter compute
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n := tmp.count + 1
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tmp.count = n
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//mean compute
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delta := x - mean
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mean = mean + delta/n
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tmp.mean = mean
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//variance/stdev compute
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M2 = M2 + delta*(x-mean)
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tmp.M2 = M2
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//max/min compute
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if fv < tmp.min {
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tmp.min = fv
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} else if fv > tmp.max {
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tmp.max = fv
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}
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//store final data
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m.cache[id].fields[k] = tmp
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}
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}
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}
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}
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func (m *BasicStats) Push(acc telegraf.Accumulator) {
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for _, aggregate := range m.cache {
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fields := map[string]interface{}{}
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for k, v := range aggregate.fields {
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fields[k+"_count"] = v.count
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fields[k+"_min"] = v.min
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fields[k+"_max"] = v.max
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fields[k+"_mean"] = v.mean
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//v.count always >=1
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if v.count > 1 {
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variance := v.M2 / (v.count - 1)
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fields[k+"_s2"] = variance
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fields[k+"_stdev"] = math.Sqrt(variance)
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}
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//if count == 1 StdDev = infinite => so I won't send data
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}
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acc.AddFields(aggregate.name, fields, aggregate.tags)
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}
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}
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func (m *BasicStats) Reset() {
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m.cache = make(map[uint64]aggregate)
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}
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func convert(in interface{}) (float64, bool) {
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switch v := in.(type) {
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case float64:
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return v, true
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case int64:
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return float64(v), true
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default:
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return 0, false
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}
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}
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func init() {
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aggregators.Add("basicstats", func() telegraf.Aggregator {
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return NewBasicStats()
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})
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}
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