CoderCookE/goaround

package stats

import (
    "log"
    "net/http"
    "time"

    "github.com/CoderCookE/goaround/internal/gracefulserver"
    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
    Durations = prometheus.NewSummaryVec(
        prometheus.SummaryOpts{
            Name:       "request_durations_seconds",
            Help:       "request latency distributions.",
            Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001, 1.0: 0.0},
        },
        []string{"stage"},
    )

    Attempts = prometheus.NewSummaryVec(
        prometheus.SummaryOpts{
            Name:       "attempts",
            Help:       "distributions of number of attempts made",
            Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001, 1.0: 0.0},
        },
        []string{},
    )

    CacheCounter = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name: "cache",
            Help: "cache hit and misses",
        },
        []string{"path", "cache"},
    )

    RequestCounter = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name: "request",
            Help: "requests",
        },
        []string{"host", "status"},
    )

    HealthGauge = prometheus.NewGaugeVec(
        prometheus.GaugeOpts{
            Name: "backends",
            Help: "number of healthy backends",
        },
        []string{"backends"},
    )

    AvailableConnectionsGauge = prometheus.NewGaugeVec(
        prometheus.GaugeOpts{
            Name: "connections",
            Help: "number of available connections",
        },
        []string{"connections"},
    )
)

func init() {
    prometheus.MustRegister(Attempts)
    prometheus.MustRegister(Durations)
    prometheus.MustRegister(CacheCounter)
    prometheus.MustRegister(HealthGauge)
    prometheus.MustRegister(AvailableConnectionsGauge)
    prometheus.MustRegister(RequestCounter)
}

func StartUp(addr string) {
    handler := promhttp.HandlerFor(
        prometheus.DefaultGatherer,
        promhttp.HandlerOpts{},
    )

    server := &http.Server{
        Addr:         addr,
        Handler:      handler,
        ReadTimeout:  10 * time.Second,
        WriteTimeout: 30 * time.Second,
    }

    graceful := gracefulserver.New(server)
    log.Printf("Starting Prometheus server on port %s", addr)
    err := graceful.ListenAndServe()
    if err != nil {
        log.Printf("Error starting Prometheus server: %s", err.Error())
    }
}