telegraf/plugins/aggregators/basicstats/basicstats.go

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package basicstats
import (
"log"
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"math"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/aggregators"
)
type BasicStats struct {
Stats []string `toml:"stats"`
cache map[uint64]aggregate
statsConfig *configuredStats
}
type configuredStats struct {
count bool
min bool
max bool
mean bool
variance bool
stdev bool
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}
func NewBasicStats() *BasicStats {
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mm := &BasicStats{}
mm.Reset()
return mm
}
type aggregate struct {
fields map[string]basicstats
name string
tags map[string]string
}
type basicstats struct {
count float64
min float64
max float64
mean float64
M2 float64 //intermedia value for variance/stdev
}
var sampleConfig = `
## General Aggregator Arguments:
## The period on which to flush & clear the aggregator.
period = "30s"
## If true, the original metric will be dropped by the
## aggregator and will not get sent to the output plugins.
drop_original = false
`
func (m *BasicStats) SampleConfig() string {
return sampleConfig
}
func (m *BasicStats) Description() string {
return "Keep the aggregate basicstats of each metric passing through."
}
func (m *BasicStats) Add(in telegraf.Metric) {
id := in.HashID()
if _, ok := m.cache[id]; !ok {
// hit an uncached metric, create caches for first time:
a := aggregate{
name: in.Name(),
tags: in.Tags(),
fields: make(map[string]basicstats),
}
for k, v := range in.Fields() {
if fv, ok := convert(v); ok {
a.fields[k] = basicstats{
count: 1,
min: fv,
max: fv,
mean: fv,
M2: 0.0,
}
}
}
m.cache[id] = a
} else {
for k, v := range in.Fields() {
if fv, ok := convert(v); ok {
if _, ok := m.cache[id].fields[k]; !ok {
// hit an uncached field of a cached metric
m.cache[id].fields[k] = basicstats{
count: 1,
min: fv,
max: fv,
mean: fv,
M2: 0.0,
}
continue
}
tmp := m.cache[id].fields[k]
//https://en.m.wikipedia.org/wiki/Algorithms_for_calculating_variance
//variable initialization
x := fv
mean := tmp.mean
M2 := tmp.M2
//counter compute
n := tmp.count + 1
tmp.count = n
//mean compute
delta := x - mean
mean = mean + delta/n
tmp.mean = mean
//variance/stdev compute
M2 = M2 + delta*(x-mean)
tmp.M2 = M2
//max/min compute
if fv < tmp.min {
tmp.min = fv
} else if fv > tmp.max {
tmp.max = fv
}
//store final data
m.cache[id].fields[k] = tmp
}
}
}
}
func (m *BasicStats) Push(acc telegraf.Accumulator) {
config := getConfiguredStats(m)
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for _, aggregate := range m.cache {
fields := map[string]interface{}{}
for k, v := range aggregate.fields {
if config.count {
fields[k+"_count"] = v.count
}
if config.min {
fields[k+"_min"] = v.min
}
if config.max {
fields[k+"_max"] = v.max
}
if config.mean {
fields[k+"_mean"] = v.mean
}
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//v.count always >=1
if v.count > 1 {
variance := v.M2 / (v.count - 1)
if config.variance {
fields[k+"_s2"] = variance
}
if config.stdev {
fields[k+"_stdev"] = math.Sqrt(variance)
}
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}
//if count == 1 StdDev = infinite => so I won't send data
}
if len(fields) > 0 {
acc.AddFields(aggregate.name, fields, aggregate.tags)
}
}
}
func parseStats(names []string) *configuredStats {
parsed := &configuredStats{}
for _, name := range names {
switch name {
case "count":
parsed.count = true
case "min":
parsed.min = true
case "max":
parsed.max = true
case "mean":
parsed.mean = true
case "s2":
parsed.variance = true
case "stdev":
parsed.stdev = true
default:
log.Printf("W! Unrecognized basic stat '%s', ignoring", name)
}
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}
return parsed
}
func defaultStats() *configuredStats {
defaults := &configuredStats{}
defaults.count = true
defaults.min = true
defaults.max = true
defaults.mean = true
defaults.variance = true
defaults.stdev = true
return defaults
}
func getConfiguredStats(m *BasicStats) *configuredStats {
if m.statsConfig == nil {
if m.Stats == nil {
m.statsConfig = defaultStats()
} else {
m.statsConfig = parseStats(m.Stats)
}
}
return m.statsConfig
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}
func (m *BasicStats) Reset() {
m.cache = make(map[uint64]aggregate)
}
func convert(in interface{}) (float64, bool) {
switch v := in.(type) {
case float64:
return v, true
case int64:
return float64(v), true
default:
return 0, false
}
}
func init() {
aggregators.Add("basicstats", func() telegraf.Aggregator {
return NewBasicStats()
})
}