statsd_exporter/registry.go

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// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"bytes"
"fmt"
"hash"
"hash/fnv"
"sort"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/statsd_exporter/pkg/clock"
"github.com/prometheus/statsd_exporter/pkg/mapper"
)
type metricType int
const (
CounterMetricType metricType = iota
GaugeMetricType
SummaryMetricType
HistogramMetricType
)
type nameHash uint64
type valueHash uint64
type labelHash struct {
// This is a hash over the label names
names nameHash
// This is a hash over the label names + label values
values valueHash
}
type metricHolder interface{}
type registeredMetric struct {
lastRegisteredAt time.Time
labels prometheus.Labels
ttl time.Duration
metric metricHolder
vecKey nameHash
}
type vectorHolder interface {
Delete(label prometheus.Labels) bool
}
type vector struct {
holder vectorHolder
refCount uint64
}
type metric struct {
metricType metricType
// Vectors key is the hash of the label names
vectors map[nameHash]*vector
// Metrics key is a hash of the label names + label values
metrics map[valueHash]*registeredMetric
}
type registry struct {
metrics map[string]metric
mapper *mapper.MetricMapper
// The below value and label variables are allocated in the registry struct
// so that we don't have to allocate them every time have to compute a label
// hash.
valueBuf, nameBuf bytes.Buffer
hasher hash.Hash64
}
func newRegistry(mapper *mapper.MetricMapper) *registry {
return &registry{
metrics: make(map[string]metric),
mapper: mapper,
hasher: fnv.New64a(),
}
}
func (r *registry) metricConflicts(metricName string, metricType metricType) bool {
vector, hasMetric := r.metrics[metricName]
if !hasMetric {
// No metric with this name exists
return false
}
if vector.metricType == metricType {
// We've found a copy of this metric with this type, but different
// labels, so it's safe to create a new one.
return false
}
// The metric exists, but it's of a different type than we're trying to
// create.
return true
}
func (r *registry) storeCounter(metricName string, hash labelHash, labels prometheus.Labels, vec *prometheus.CounterVec, c prometheus.Counter, ttl time.Duration) {
r.store(metricName, hash, labels, vec, c, CounterMetricType, ttl)
}
func (r *registry) storeGauge(metricName string, hash labelHash, labels prometheus.Labels, vec *prometheus.GaugeVec, g prometheus.Counter, ttl time.Duration) {
r.store(metricName, hash, labels, vec, g, GaugeMetricType, ttl)
}
func (r *registry) storeHistogram(metricName string, hash labelHash, labels prometheus.Labels, vec *prometheus.HistogramVec, o prometheus.Observer, ttl time.Duration) {
r.store(metricName, hash, labels, vec, o, HistogramMetricType, ttl)
}
func (r *registry) storeSummary(metricName string, hash labelHash, labels prometheus.Labels, vec *prometheus.SummaryVec, o prometheus.Observer, ttl time.Duration) {
r.store(metricName, hash, labels, vec, o, SummaryMetricType, ttl)
}
func (r *registry) store(metricName string, hash labelHash, labels prometheus.Labels, vh vectorHolder, mh metricHolder, metricType metricType, ttl time.Duration) {
metric, hasMetric := r.metrics[metricName]
if !hasMetric {
metric.metricType = metricType
metric.vectors = make(map[nameHash]*vector)
metric.metrics = make(map[valueHash]*registeredMetric)
r.metrics[metricName] = metric
}
v, ok := metric.vectors[hash.names]
if !ok {
v = &vector{holder: vh}
metric.vectors[hash.names] = v
}
rm, ok := metric.metrics[hash.values]
if !ok {
rm = &registeredMetric{
labels: labels,
ttl: ttl,
metric: mh,
vecKey: hash.names,
}
metric.metrics[hash.values] = rm
v.refCount++
}
now := clock.Now()
rm.lastRegisteredAt = now
// Update ttl from mapping
rm.ttl = ttl
}
func (r *registry) get(metricName string, hash labelHash, metricType metricType) (vectorHolder, metricHolder) {
metric, hasMetric := r.metrics[metricName]
if !hasMetric {
return nil, nil
}
if metric.metricType != metricType {
return nil, nil
}
rm, ok := metric.metrics[hash.values]
if ok {
now := clock.Now()
rm.lastRegisteredAt = now
return metric.vectors[hash.names].holder, rm.metric
}
vector, ok := metric.vectors[hash.names]
if ok {
return vector.holder, nil
}
return nil, nil
}
func (r *registry) getCounter(metricName string, labels prometheus.Labels, help string, mapping *mapper.MetricMapping) (prometheus.Counter, error) {
hash, labelNames := r.hashLabels(labels)
vh, mh := r.get(metricName, hash, CounterMetricType)
if mh != nil {
return mh.(prometheus.Counter), nil
}
if r.metricConflicts(metricName, CounterMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
var counterVec *prometheus.CounterVec
if vh == nil {
metricsCount.WithLabelValues("counter").Inc()
counterVec = prometheus.NewCounterVec(prometheus.CounterOpts{
Name: metricName,
Help: help,
}, labelNames)
if err := prometheus.Register(uncheckedCollector{counterVec}); err != nil {
return nil, err
}
} else {
counterVec = vh.(*prometheus.CounterVec)
}
var counter prometheus.Counter
var err error
if counter, err = counterVec.GetMetricWith(labels); err != nil {
return nil, err
}
r.storeCounter(metricName, hash, labels, counterVec, counter, mapping.Ttl)
return counter, nil
}
func (r *registry) getGauge(metricName string, labels prometheus.Labels, help string, mapping *mapper.MetricMapping) (prometheus.Gauge, error) {
hash, labelNames := r.hashLabels(labels)
vh, mh := r.get(metricName, hash, GaugeMetricType)
if mh != nil {
return mh.(prometheus.Gauge), nil
}
if r.metricConflicts(metricName, GaugeMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
var gaugeVec *prometheus.GaugeVec
if vh == nil {
metricsCount.WithLabelValues("gauge").Inc()
gaugeVec = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Name: metricName,
Help: help,
}, labelNames)
if err := prometheus.Register(uncheckedCollector{gaugeVec}); err != nil {
return nil, err
}
} else {
gaugeVec = vh.(*prometheus.GaugeVec)
}
var gauge prometheus.Gauge
var err error
if gauge, err = gaugeVec.GetMetricWith(labels); err != nil {
return nil, err
}
r.storeGauge(metricName, hash, labels, gaugeVec, gauge, mapping.Ttl)
return gauge, nil
}
func (r *registry) getHistogram(metricName string, labels prometheus.Labels, help string, mapping *mapper.MetricMapping) (prometheus.Observer, error) {
hash, labelNames := r.hashLabels(labels)
vh, mh := r.get(metricName, hash, HistogramMetricType)
if mh != nil {
return mh.(prometheus.Observer), nil
}
if r.metricConflicts(metricName, HistogramMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
if r.metricConflicts(metricName+"_sum", HistogramMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
if r.metricConflicts(metricName+"_count", HistogramMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
if r.metricConflicts(metricName+"_bucket", HistogramMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
var histogramVec *prometheus.HistogramVec
if vh == nil {
metricsCount.WithLabelValues("histogram").Inc()
buckets := r.mapper.Defaults.Buckets
if mapping.Buckets != nil && len(mapping.Buckets) > 0 {
buckets = mapping.Buckets
}
histogramVec = prometheus.NewHistogramVec(prometheus.HistogramOpts{
Name: metricName,
Help: help,
Buckets: buckets,
}, labelNames)
if err := prometheus.Register(uncheckedCollector{histogramVec}); err != nil {
return nil, err
}
} else {
histogramVec = vh.(*prometheus.HistogramVec)
}
var observer prometheus.Observer
var err error
if observer, err = histogramVec.GetMetricWith(labels); err != nil {
return nil, err
}
r.storeHistogram(metricName, hash, labels, histogramVec, observer, mapping.Ttl)
return observer, nil
}
func (r *registry) getSummary(metricName string, labels prometheus.Labels, help string, mapping *mapper.MetricMapping) (prometheus.Observer, error) {
hash, labelNames := r.hashLabels(labels)
vh, mh := r.get(metricName, hash, SummaryMetricType)
if mh != nil {
return mh.(prometheus.Observer), nil
}
if r.metricConflicts(metricName, SummaryMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
if r.metricConflicts(metricName+"_sum", SummaryMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
if r.metricConflicts(metricName+"_count", SummaryMetricType) {
return nil, fmt.Errorf("metric with name %s is already registered", metricName)
}
var summaryVec *prometheus.SummaryVec
if vh == nil {
metricsCount.WithLabelValues("summary").Inc()
quantiles := r.mapper.Defaults.Quantiles
if mapping != nil && mapping.Quantiles != nil && len(mapping.Quantiles) > 0 {
quantiles = mapping.Quantiles
}
objectives := make(map[float64]float64)
for _, q := range quantiles {
objectives[q.Quantile] = q.Error
}
// In the case of no mapping file, explicitly define the default quantiles
if len(objectives) == 0 {
objectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
}
summaryVec = prometheus.NewSummaryVec(prometheus.SummaryOpts{
Name: metricName,
Help: help,
Objectives: objectives,
}, labelNames)
if err := prometheus.Register(uncheckedCollector{summaryVec}); err != nil {
return nil, err
}
} else {
summaryVec = vh.(*prometheus.SummaryVec)
}
var observer prometheus.Observer
var err error
if observer, err = summaryVec.GetMetricWith(labels); err != nil {
return nil, err
}
r.storeSummary(metricName, hash, labels, summaryVec, observer, mapping.Ttl)
return observer, nil
}
func (r *registry) removeStaleMetrics() {
now := clock.Now()
// delete timeseries with expired ttl
for _, metric := range r.metrics {
for hash, rm := range metric.metrics {
if rm.ttl == 0 {
continue
}
if rm.lastRegisteredAt.Add(rm.ttl).Before(now) {
metric.vectors[rm.vecKey].holder.Delete(rm.labels)
metric.vectors[rm.vecKey].refCount--
delete(metric.metrics, hash)
}
}
}
}
// Calculates a hash of both the label names and the label names and values.
func (r *registry) hashLabels(labels prometheus.Labels) (labelHash, []string) {
r.hasher.Reset()
r.nameBuf.Reset()
r.valueBuf.Reset()
labelNames := make([]string, 0, len(labels))
for labelName := range labels {
labelNames = append(labelNames, labelName)
}
sort.Strings(labelNames)
r.valueBuf.WriteByte(model.SeparatorByte)
for _, labelName := range labelNames {
r.valueBuf.WriteString(labels[labelName])
r.valueBuf.WriteByte(model.SeparatorByte)
r.nameBuf.WriteString(labelName)
r.nameBuf.WriteByte(model.SeparatorByte)
}
lh := labelHash{}
r.hasher.Write(r.nameBuf.Bytes())
lh.names = nameHash(r.hasher.Sum64())
// Now add the values to the names we've already hashed.
r.hasher.Write(r.valueBuf.Bytes())
lh.values = valueHash(r.hasher.Sum64())
return lh, labelNames
}