package librato
import (
"fmt"
"log"
"math"
"regexp"
"time"
"github.com/dexon-foundation/dexon/metrics"
)
// a regexp for extracting the unit from time.Duration.String
var unitRegexp = regexp.MustCompile(`[^\\d]+$`)
// a helper that turns a time.Duration into librato display attributes for timer metrics
func translateTimerAttributes(d time.Duration) (attrs map[string]interface{}) {
attrs = make(map[string]interface{})
attrs[DisplayTransform] = fmt.Sprintf("x/%d", int64(d))
attrs[DisplayUnitsShort] = string(unitRegexp.Find([]byte(d.String())))
return
}
type Reporter struct {
Email, Token string
Namespace string
Source string
Interval time.Duration
Registry metrics.Registry
Percentiles []float64 // percentiles to report on histogram metrics
TimerAttributes map[string]interface{} // units in which timers will be displayed
intervalSec int64
}
func NewReporter(r metrics.Registry, d time.Duration, e string, t string, s string, p []float64, u time.Duration) *Reporter {
return &Reporter{e, t, "", s, d, r, p, translateTimerAttributes(u), int64(d / time.Second)}
}
func Librato(r metrics.Registry, d time.Duration, e string, t string, s string, p []float64, u time.Duration) {
NewReporter(r, d, e, t, s, p, u).Run()
}
func (rep *Reporter) Run() {
log.Printf("WARNING: This client has been DEPRECATED! It has been moved to https://github.com/mihasya/go-metrics-librato and will be removed from rcrowley/go-metrics on August 5th 2015")
ticker := time.Tick(rep.Interval)
metricsApi := &LibratoClient{rep.Email, rep.Token}
for now := range ticker {
var metrics Batch
var err error
if metrics, err = rep.BuildRequest(now, rep.Registry); err != nil {
log.Printf("ERROR constructing librato request body %s", err)
continue
}
if err := metricsApi.PostMetrics(metrics); err != nil {
log.Printf("ERROR sending metrics to librato %s", err)
continue
}
}
}
// calculate sum of squares from data provided by metrics.Histogram
// see http://en.wikipedia.org/wiki/Standard_deviation#Rapid_calculation_methods
func sumSquares(s metrics.Sample) float64 {
count := float64(s.Count())
sumSquared := math.Pow(count*s.Mean(), 2)
sumSquares := math.Pow(count*s.StdDev(), 2) + sumSquared/count
if math.IsNaN(sumSquares) {
return 0.0
}
return sumSquares
}
func sumSquaresTimer(t metrics.Timer) float64 {
count := float64(t.Count())
sumSquared := math.Pow(count*t.Mean(), 2)
sumSquares := math.Pow(count*t.StdDev(), 2) + sumSquared/count
if math.IsNaN(sumSquares) {
return 0.0
}
return sumSquares
}
func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot Batch, err error) {
snapshot = Batch{
// coerce timestamps to a stepping fn so that they line up in Librato graphs
MeasureTime: (now.Unix() / rep.intervalSec) * rep.intervalSec,
Source: rep.Source,
}
snapshot.Gauges = make([]Measurement, 0)
snapshot.Counters = make([]Measurement, 0)
histogramGaugeCount := 1 + len(rep.Percentiles)
r.Each(func(name string, metric interface{}) {
if rep.Namespace != "" {
name = fmt.Sprintf("%s.%s", rep.Namespace, name)
}
measurement := Measurement{}
measurement[Period] = rep.Interval.Seconds()
switch m := metric.(type) {
case metrics.Counter:
if m.Count() > 0 {
measurement[Name] = fmt.Sprintf("%s.%s", name, "count")
measurement[Value] = float64(m.Count())
measurement[Attributes] = map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
}
snapshot.Counters = append(snapshot.Counters, measurement)
}
case metrics.Gauge:
measurement[Name] = name
measurement[Value] = float64(m.Value())
snapshot.Gauges = append(snapshot.Gauges, measurement)
case metrics.GaugeFloat64:
measurement[Name] = name
measurement[Value] = m.Value()
snapshot.Gauges = append(snapshot.Gauges, measurement)
case metrics.Histogram:
if m.Count() > 0 {
gauges := make([]Measurement, histogramGaugeCount)
s := m.Sample()
measurement[Name] = fmt.Sprintf("%s.%s", name, "hist")
measurement[Count] = uint64(s.Count())
measurement[Max] = float64(s.Max())
measurement[Min] = float64(s.Min())
measurement[Sum] = float64(s.Sum())
measurement[SumSquares] = sumSquares(s)
gauges[0] = measurement
for i, p := range rep.Percentiles {
gauges[i+1] = Measurement{
Name: fmt.Sprintf("%s.%.2f", measurement[Name], p),
Value: s.Percentile(p),
Period: measurement[Period],
}
}
snapshot.Gauges = append(snapshot.Gauges, gauges...)
}
case metrics.Meter:
measurement[Name] = name
measurement[Value] = float64(m.Count())
snapshot.Counters = append(snapshot.Counters, measurement)
snapshot.Gauges = append(snapshot.Gauges,
Measurement{
Name: fmt.Sprintf("%s.%s", name, "1min"),
Value: m.Rate1(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "5min"),
Value: m.Rate5(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "15min"),
Value: m.Rate15(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
)
case metrics.Timer:
measurement[Name] = name
measurement[Value] = float64(m.Count())
snapshot.Counters = append(snapshot.Counters, measurement)
if m.Count() > 0 {
libratoName := fmt.Sprintf("%s.%s", name, "timer.mean")
gauges := make([]Measurement, histogramGaugeCount)
gauges[0] = Measurement{
Name: libratoName,
Count: uint64(m.Count()),
Sum: m.Mean() * float64(m.Count()),
Max: float64(m.Max()),
Min: float64(m.Min()),
SumSquares: sumSquaresTimer(m),
Period: int64(rep.Interval.Seconds()),
Attributes: rep.TimerAttributes,
}
for i, p := range rep.Percentiles {
gauges[i+1] = Measurement{
Name: fmt.Sprintf("%s.timer.%2.0f", name, p*100),
Value: m.Percentile(p),
Period: int64(rep.Interval.Seconds()),
Attributes: rep.TimerAttributes,
}
}
snapshot.Gauges = append(snapshot.Gauges, gauges...)
snapshot.Gauges = append(snapshot.Gauges,
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.1min"),
Value: m.Rate1(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.5min"),
Value: m.Rate5(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.15min"),
Value: m.Rate15(),
Period: int64(rep.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
)
}
}
})
return
}
