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// +build go1.3
package prometheus
import (
"fmt"
"log"
"strings"
"sync"
"time"
"regexp"
"github.com/armon/go-metrics"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/push"
)
var (
// DefaultPrometheusOpts is the default set of options used when creating a
// PrometheusSink.
DefaultPrometheusOpts = PrometheusOpts{
Expiration: 60 * time.Second,
}
)
// PrometheusOpts is used to configure the Prometheus Sink
type PrometheusOpts struct {
// Expiration is the duration a metric is valid for, after which it will be
// untracked. If the value is zero, a metric is never expired.
Expiration time.Duration
}
type PrometheusSink struct {
mu sync.Mutex
gauges map[string]prometheus.Gauge
summaries map[string]prometheus.Summary
counters map[string]prometheus.Counter
updates map[string]time.Time
expiration time.Duration
}
// NewPrometheusSink creates a new PrometheusSink using the default options.
func NewPrometheusSink() (*PrometheusSink, error) {
return NewPrometheusSinkFrom(DefaultPrometheusOpts)
}
// NewPrometheusSinkFrom creates a new PrometheusSink using the passed options.
func NewPrometheusSinkFrom(opts PrometheusOpts) (*PrometheusSink, error) {
sink := &PrometheusSink{
gauges: make(map[string]prometheus.Gauge),
summaries: make(map[string]prometheus.Summary),
counters: make(map[string]prometheus.Counter),
updates: make(map[string]time.Time),
expiration: opts.Expiration,
}
return sink, prometheus.Register(sink)
}
// Describe is needed to meet the Collector interface.
func (p *PrometheusSink) Describe(c chan<- *prometheus.Desc) {
// We must emit some description otherwise an error is returned. This
// description isn't shown to the user!
prometheus.NewGauge(prometheus.GaugeOpts{Name: "Dummy", Help: "Dummy"}).Describe(c)
}
// Collect meets the collection interface and allows us to enforce our expiration
// logic to clean up ephemeral metrics if their value haven't been set for a
// duration exceeding our allowed expiration time.
func (p *PrometheusSink) Collect(c chan<- prometheus.Metric) {
p.mu.Lock()
defer p.mu.Unlock()
expire := p.expiration != 0
now := time.Now()
for k, v := range p.gauges {
last := p.updates[k]
if expire && last.Add(p.expiration).Before(now) {
delete(p.updates, k)
delete(p.gauges, k)
} else {
v.Collect(c)
}
}
for k, v := range p.summaries {
last := p.updates[k]
if expire && last.Add(p.expiration).Before(now) {
delete(p.updates, k)
delete(p.summaries, k)
} else {
v.Collect(c)
}
}
for k, v := range p.counters {
last := p.updates[k]
if expire && last.Add(p.expiration).Before(now) {
delete(p.updates, k)
delete(p.counters, k)
} else {
v.Collect(c)
}
}
}
var forbiddenChars = regexp.MustCompile("[ .=\\-/]")
func (p *PrometheusSink) flattenKey(parts []string, labels []metrics.Label) (string, string) {
key := strings.Join(parts, "_")
key = forbiddenChars.ReplaceAllString(key, "_")
hash := key
for _, label := range labels {
hash += fmt.Sprintf(";%s=%s", label.Name, label.Value)
}
return key, hash
}
func prometheusLabels(labels []metrics.Label) prometheus.Labels {
l := make(prometheus.Labels)
for _, label := range labels {
l[label.Name] = label.Value
}
return l
}
func (p *PrometheusSink) SetGauge(parts []string, val float32) {
p.SetGaugeWithLabels(parts, val, nil)
}
func (p *PrometheusSink) SetGaugeWithLabels(parts []string, val float32, labels []metrics.Label) {
p.mu.Lock()
defer p.mu.Unlock()
key, hash := p.flattenKey(parts, labels)
g, ok := p.gauges[hash]
if !ok {
g = prometheus.NewGauge(prometheus.GaugeOpts{
Name: key,
Help: key,
ConstLabels: prometheusLabels(labels),
})
p.gauges[hash] = g
}
g.Set(float64(val))
p.updates[hash] = time.Now()
}
func (p *PrometheusSink) AddSample(parts []string, val float32) {
p.AddSampleWithLabels(parts, val, nil)
}
func (p *PrometheusSink) AddSampleWithLabels(parts []string, val float32, labels []metrics.Label) {
p.mu.Lock()
defer p.mu.Unlock()
key, hash := p.flattenKey(parts, labels)
g, ok := p.summaries[hash]
if !ok {
g = prometheus.NewSummary(prometheus.SummaryOpts{
Name: key,
Help: key,
MaxAge: 10 * time.Second,
ConstLabels: prometheusLabels(labels),
Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
})
p.summaries[hash] = g
}
g.Observe(float64(val))
p.updates[hash] = time.Now()
}
// EmitKey is not implemented. Prometheus doesn’t offer a type for which an
// arbitrary number of values is retained, as Prometheus works with a pull
// model, rather than a push model.
func (p *PrometheusSink) EmitKey(key []string, val float32) {
}
func (p *PrometheusSink) IncrCounter(parts []string, val float32) {
p.IncrCounterWithLabels(parts, val, nil)
}
func (p *PrometheusSink) IncrCounterWithLabels(parts []string, val float32, labels []metrics.Label) {
p.mu.Lock()
defer p.mu.Unlock()
key, hash := p.flattenKey(parts, labels)
g, ok := p.counters[hash]
if !ok {
g = prometheus.NewCounter(prometheus.CounterOpts{
Name: key,
Help: key,
ConstLabels: prometheusLabels(labels),
})
p.counters[hash] = g
}
g.Add(float64(val))
p.updates[hash] = time.Now()
}
type PrometheusPushSink struct {
*PrometheusSink
pusher *push.Pusher
address string
pushInterval time.Duration
stopChan chan struct{}
}
func NewPrometheusPushSink(address string, pushIterval time.Duration, name string) (*PrometheusPushSink, error) {
promSink := &PrometheusSink{
gauges: make(map[string]prometheus.Gauge),
summaries: make(map[string]prometheus.Summary),
counters: make(map[string]prometheus.Counter),
updates: make(map[string]time.Time),
expiration: 60 * time.Second,
}
pusher := push.New(address, name).Collector(promSink)
sink := &PrometheusPushSink{
promSink,
pusher,
address,
pushIterval,
make(chan struct{}),
}
sink.flushMetrics()
return sink, nil
}
func (s *PrometheusPushSink) flushMetrics() {
ticker := time.NewTicker(s.pushInterval)
go func() {
for {
select {
case <-ticker.C:
err := s.pusher.Push()
if err != nil {
log.Printf("[ERR] Error pushing to Prometheus! Err: %s", err)
}
case <-s.stopChan:
ticker.Stop()
return
}
}
}()
}
func (s *PrometheusPushSink) Shutdown() {
close(s.stopChan)
}
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