micro/meter/meter.go

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// Package meter is for instrumentation
package meter // import "go.unistack.org/micro/v3/meter"
import (
"io"
"sort"
"strconv"
"strings"
"time"
)
var (
// DefaultMeter is the default meter
DefaultMeter Meter = NewMeter()
// DefaultAddress data will be made available on this host:port
DefaultAddress = ":9090"
// DefaultPath the meter endpoint where the Meter data will be made available
DefaultPath = "/metrics"
// DefaultMetricPrefix holds the string that prepends to all metrics
DefaultMetricPrefix = "micro_"
// DefaultLabelPrefix holds the string that prepends to all labels
DefaultLabelPrefix = "micro_"
// DefaultSummaryQuantiles is the default spread of stats for summary
DefaultSummaryQuantiles = []float64{0.5, 0.9, 0.97, 0.99, 1}
// DefaultSummaryWindow is the default window for summary
DefaultSummaryWindow = 5 * time.Minute
)
// Meter is an interface for collecting and instrumenting metrics
type Meter interface {
Name() string
Init(opts ...Option) error
Counter(name string, labels ...string) Counter
FloatCounter(name string, labels ...string) FloatCounter
Gauge(name string, fn func() float64, labels ...string) Gauge
Set(opts ...Option) Meter
Histogram(name string, labels ...string) Histogram
Summary(name string, labels ...string) Summary
SummaryExt(name string, window time.Duration, quantiles []float64, labels ...string) Summary
Write(w io.Writer, opts ...Option) error
Options() Options
String() string
}
// Counter is a counter
type Counter interface {
Add(int)
Dec()
Get() uint64
Inc()
Set(uint64)
}
// FloatCounter is a float64 counter
type FloatCounter interface {
Add(float64)
Get() float64
Set(float64)
Sub(float64)
}
// Gauge is a float64 gauge
type Gauge interface {
Get() float64
}
// Histogram is a histogram for non-negative values with automatically created buckets
type Histogram interface {
Reset()
Update(float64)
UpdateDuration(time.Time)
// VisitNonZeroBuckets(f func(vmrange string, count uint64))
}
// Summary is the summary
type Summary interface {
Update(float64)
UpdateDuration(time.Time)
}
// sort labels alphabeticaly by label name
type byKey []string
func (k byKey) Len() int { return len(k) / 2 }
func (k byKey) Less(i, j int) bool { return k[i*2] < k[j*2] }
func (k byKey) Swap(i, j int) {
k[i*2], k[j*2] = k[j*2], k[i*2]
k[i*2+1], k[j*2+1] = k[j*2+1], k[i*2+1]
}
// BuildLables used to sort labels and delete duplicates.
// Last value wins in case of duplicate label keys.
func BuildLabels(labels ...string) []string {
if len(labels)%2 == 1 {
labels = labels[:len(labels)-1]
}
sort.Sort(byKey(labels))
return labels
}
// BuildName used to combine metric with labels.
// If labels count is odd, drop last element
func BuildName(name string, labels ...string) string {
if len(labels)%2 == 1 {
labels = labels[:len(labels)-1]
}
if len(labels) > 2 {
sort.Sort(byKey(labels))
idx := 0
for {
if labels[idx] == labels[idx+2] {
copy(labels[idx:], labels[idx+2:])
labels = labels[:len(labels)-2]
} else {
idx += 2
}
if idx+2 >= len(labels) {
break
}
}
}
var b strings.Builder
_, _ = b.WriteString(name)
_, _ = b.WriteRune('{')
for idx := 0; idx < len(labels); idx += 2 {
if idx > 0 {
_, _ = b.WriteRune(',')
}
_, _ = b.WriteString(labels[idx])
_, _ = b.WriteString(`=`)
_, _ = b.WriteString(strconv.Quote(labels[idx+1]))
}
_, _ = b.WriteRune('}')
return b.String()
}