main.go

package main

import (
	"context"
	"errors"
	"flag"
	"log/slog"
	"net/http"
	"os"

	"github.com/gorilla/mux"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/spf13/viper"
	"k8s.io/client-go/kubernetes"
)

type App interface {
	Start()
}

type app struct {
	ctx               context.Context
	client            *kubernetes.Clientset
	config            *viper.Viper
	deployedNamespace string
	namespace         string
	targetService     string
}

func newApp(
	ctx context.Context,
	client *kubernetes.Clientset,
	config *viper.Viper,
) App {
	return &app{
		ctx:               ctx,
		client:            client,
		config:            config,
		deployedNamespace: getDeployedNamespace(),
		namespace:         getVaultNamespace(),
		targetService:     getTargetService(),
	}
}

func (a *app) Start() {
	go func() {
		r := mux.NewRouter()
		r.HandleFunc("/metrics", promhttp.Handler().ServeHTTP)
		srv := &http.Server{
			Addr:    ":8080",
			Handler: r,
		}
		slog.Info("Starting metrics server")
		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			slog.Error("Error starting metrics server", slog.String(loggingKeyError, err.Error()))
			os.Exit(1)
		}
	}()

	for {
		select {
		case <-a.ctx.Done():
			return
		default:
			a.watchNewPods()

			slog.Debug("Watch new pods ended, trying to reconnect")
		}
	}
}

func init() {
	flag.Parse()
	initializeLogger()
}

func main() {
	a, err := InitializeApp()
	if err != nil {
		slog.Error("Error initializing app", slog.String(loggingKeyError, err.Error()))
		os.Exit(1)
	} else if a == nil {
		slog.Error("App is nil")
		os.Exit(1)
	}
	a.Start()
}