main.go

package main

import (
	"context"
	"errors"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

func main() {
	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}

	mux := http.NewServeMux()
	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})

	srv := &http.Server{
		Addr:    ":" + port,
		Handler: mux,
	}

	go func() {
		log.Printf("core-go listening on :%s", port)
		if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			log.Fatalf("server error: %v", err)
		}
	}()

	stop := make(chan os.Signal, 1)
	signal.Notify(stop, syscall.SIGINT, syscall.SIGTERM)
	<-stop

	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		log.Fatalf("shutdown error: %v", err)
	}
	log.Println("core-go stopped")
}