1919913c98
If external plugins wanted to extend metrics there was no way since zoneNames couldn't be initialized. Now plugins can call New to get an instance of Metrics that they can extend.
106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
// Package metrics implement a handler and plugin 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/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/metrics/vars"
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"github.com/prometheus/client_golang/prometheus"
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)
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func init() {
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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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}
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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 plugin.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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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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// New returns a new instance of Metrics with the given address
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func New(addr string) *Metrics {
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return &Metrics{Addr: addr, zoneMap: make(map[string]bool)}
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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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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 err
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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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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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return nil
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}
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// OnShutdown tears down the metrics on shutdown and restart.
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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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