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ListenAddr is the address where the prometheus metric are exported. This can be used in tests to listen on "localhost:0" and then later retrieve the metrics from there. It makes the tests indepent on each other.
105 lines
2.2 KiB
Go
105 lines
2.2 KiB
Go
// Package metrics implement a handler and middleware that provides Prometheus metrics.
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package metrics
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import (
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"log"
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"net"
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"net/http"
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"sync"
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"github.com/miekg/coredns/middleware"
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"github.com/miekg/coredns/middleware/metrics/vars"
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"github.com/prometheus/client_golang/prometheus"
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)
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// Metrics holds the prometheus configuration. The metrics' path is fixed to be /metrics
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type Metrics struct {
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Next middleware.Handler
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Addr string
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ln net.Listener
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mux *http.ServeMux
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Once sync.Once
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zoneNames []string
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zoneMap map[string]bool
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zoneMu sync.RWMutex
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}
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// AddZone adds zone z to m.
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func (m *Metrics) AddZone(z string) {
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m.zoneMu.Lock()
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m.zoneMap[z] = true
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m.zoneNames = keys(m.zoneMap)
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m.zoneMu.Unlock()
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}
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// RemoveZone remove zone z from m.
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func (m *Metrics) RemoveZone(z string) {
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m.zoneMu.Lock()
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delete(m.zoneMap, z)
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m.zoneNames = keys(m.zoneMap)
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m.zoneMu.Unlock()
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}
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// ZoneNames returns the zones of m.
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func (m *Metrics) ZoneNames() []string {
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m.zoneMu.RLock()
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s := m.zoneNames
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m.zoneMu.RUnlock()
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return s
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}
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// OnStartup sets up the metrics on startup.
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func (m *Metrics) OnStartup() error {
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m.Once.Do(func() {
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ln, err := net.Listen("tcp", m.Addr)
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if err != nil {
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log.Printf("[ERROR] Failed to start metrics handler: %s", err)
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return
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}
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m.ln = ln
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ListenAddr = m.ln.Addr().String()
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m.mux = http.NewServeMux()
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prometheus.MustRegister(vars.RequestCount)
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prometheus.MustRegister(vars.RequestDuration)
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prometheus.MustRegister(vars.RequestSize)
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prometheus.MustRegister(vars.RequestDo)
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prometheus.MustRegister(vars.RequestType)
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prometheus.MustRegister(vars.ResponseSize)
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prometheus.MustRegister(vars.ResponseRcode)
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m.mux.Handle("/metrics", prometheus.Handler())
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go func() {
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http.Serve(m.ln, m.mux)
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}()
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})
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return nil
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}
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// OnShutdown tears down the metrics on shutdown.
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func (m *Metrics) OnShutdown() error {
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if m.ln != nil {
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return m.ln.Close()
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}
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return nil
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}
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func keys(m map[string]bool) []string {
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sx := []string{}
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for k := range m {
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sx = append(sx, k)
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}
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return sx
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}
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// ListenAddr is assigned the address of the prometheus listener. Its use is mainly in tests where
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// we listen on "localhost:0" and need to retrieve the actual address.
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var ListenAddr string
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