Files
egress-proxies-operator/internal/metrics/metrics.go

120 lines
4.3 KiB
Go

// Package metrics defines the operator's Prometheus metrics. Nothing here
// registers itself — no init(), per house rules — the composition root
// calls Register explicitly, which also lets every test use a fresh
// registry.
package metrics
import (
"time"
"github.com/prometheus/client_golang/prometheus"
)
// Metrics holds the vector metrics the operator's components feed. The
// consuming packages (health, discovery, provider) each define their own
// small recorder interface; *Metrics satisfies all of them structurally,
// so none of them import this package's prometheus surface.
type Metrics struct {
healthcheckDuration *prometheus.HistogramVec
healthcheckFailures *prometheus.CounterVec
leaseRequests *prometheus.CounterVec
providerRequests *prometheus.CounterVec
}
// New builds the metric set, unregistered.
func New() *Metrics {
return &Metrics{
healthcheckDuration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
Name: "proxy_operator_healthcheck_duration_seconds",
Help: "Duration of through-the-proxy health probes.",
Buckets: prometheus.DefBuckets,
}, []string{"proxy"}),
healthcheckFailures: prometheus.NewCounterVec(prometheus.CounterOpts{
Name: "proxy_operator_healthcheck_failures_total",
Help: "Failed health probes.",
}, []string{"proxy"}),
leaseRequests: prometheus.NewCounterVec(prometheus.CounterOpts{
Name: "proxy_operator_lease_requests_total",
Help: "Lease acquisition requests by outcome.",
}, []string{"outcome"}),
providerRequests: prometheus.NewCounterVec(prometheus.CounterOpts{
Name: "proxy_operator_provider_requests_total",
Help: "Provider API calls by operation and classified result.",
}, []string{"provider", "op", "result"}),
}
}
// Register registers the vectors plus the two scrape-time collectors.
// proxyPhases and activeLeases are read at every scrape: gauges derived
// from reconcile-time increments inevitably drift and leak series on
// delete; reading the source of truth cannot.
func (m *Metrics) Register(reg prometheus.Registerer, proxyPhases func() map[string]int, activeLeases func() int) error {
collectors := []prometheus.Collector{
m.healthcheckDuration,
m.healthcheckFailures,
m.leaseRequests,
m.providerRequests,
&constCollector{
desc: prometheus.NewDesc("proxy_operator_proxies",
"Proxy objects by phase.", []string{"phase"}, nil),
read: proxyPhases,
},
&constCollector{
desc: prometheus.NewDesc("proxy_operator_leases_active",
"Currently active leases.", nil, nil),
read: func() map[string]int { return map[string]int{"": activeLeases()} },
},
}
for _, c := range collectors {
if err := reg.Register(c); err != nil {
return err
}
}
return nil
}
// ObserveProbe records one health probe. Called on every probe — metrics
// are the home for high-frequency signal that must never touch status.
func (m *Metrics) ObserveProbe(proxy string, latency time.Duration, success bool) {
m.healthcheckDuration.WithLabelValues(proxy).Observe(latency.Seconds())
if !success {
m.healthcheckFailures.WithLabelValues(proxy).Inc()
}
}
// ForgetProxy drops the per-proxy series when the health engine prunes its
// state — without this, series for deleted proxies leak forever.
func (m *Metrics) ForgetProxy(proxy string) {
m.healthcheckDuration.DeleteLabelValues(proxy)
m.healthcheckFailures.DeleteLabelValues(proxy)
}
// LeaseRequest records a lease acquisition outcome ("granted"|"no_match").
func (m *Metrics) LeaseRequest(outcome string) {
m.leaseRequests.WithLabelValues(outcome).Inc()
}
// ProviderRequest records one provider API call with its classified result.
func (m *Metrics) ProviderRequest(provider, op, result string) {
m.providerRequests.WithLabelValues(provider, op, result).Inc()
}
// constCollector reads a label→value map at scrape time and emits one
// gauge sample per entry. An empty-string label key means "no labels".
type constCollector struct {
desc *prometheus.Desc
read func() map[string]int
}
func (c *constCollector) Describe(ch chan<- *prometheus.Desc) { ch <- c.desc }
func (c *constCollector) Collect(ch chan<- prometheus.Metric) {
for label, value := range c.read() {
if label == "" {
ch <- prometheus.MustNewConstMetric(c.desc, prometheus.GaugeValue, float64(value))
continue
}
ch <- prometheus.MustNewConstMetric(c.desc, prometheus.GaugeValue, float64(value), label)
}
}