waku-org/go-waku

package metrics

import (
    "context"
    "fmt"
    "net/http"

    "github.com/prometheus/client_golang/prometheus/promhttp"
    "go.opencensus.io/plugin/ochttp"
    "go.uber.org/zap"
)

// Server runs and controls a HTTP pprof interface.
type Server struct {
    server *http.Server
    log    *zap.Logger
}

// NewMetricsServer creates a prometheus server on a particular interface and port
func NewMetricsServer(address string, port int, log *zap.Logger) *Server {
    p := Server{
        log: log.Named("metrics"),
    }

    p.log.Info("starting server", zap.String("address", address), zap.Int("port", port))
    mux := http.NewServeMux()
    mux.Handle("/metrics", promhttp.Handler())

    // Healthcheck
    mux.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprint(w, "OK")
    })

    h := &ochttp.Handler{Handler: mux}

    p.server = &http.Server{
        Addr:    fmt.Sprintf("%s:%d", address, port),
        Handler: h,
    }

    return &p
}

// Start executes the HTTP server in the background.
func (p *Server) Start() {
    p.log.Info("server started ", zap.Error(p.server.ListenAndServe()))
}

// Stop shuts down the prometheus server
func (p *Server) Stop(ctx context.Context) error {
    err := p.server.Shutdown(ctx)
    if err != nil {
        p.log.Error("stopping server", zap.Error(err))
        return err
    }

    return nil
}