server.go

package main

import (
	"context"
	"net/http"

	"github.com/go-chi/chi"
	"github.com/sirupsen/logrus"
	"golang.org/x/sync/errgroup"
)

// HandleIndex writes cookie to brower
func HandleIndex() http.HandlerFunc {
	fn := func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Cookie", "__session__=1")
	}

	return http.HandlerFunc(fn)
}

func main() {
	ctx := context.Background()

	var g errgroup.Group

	r := chi.NewRouter()

	r.Get("/", HandleIndex())

	s := http.Server{
		Addr:    ":3000",
		Handler: r,
	}

	g.Go(func() error {
		return s.ListenAndServe()
	})

	g.Go(func() error {
		<-ctx.Done()
		return s.Shutdown(ctx)
	})

	if err := g.Wait(); err != nil {
		logrus.Debugln("server stopped", err)
	}

}