main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"strings"
	"time"

	"github.com/adnaan/gomodest-starter/app"

	"github.com/go-chi/chi"

	"github.com/go-chi/valve"
)

// fileServer conveniently sets up a http.FileServer handler to serve
// static files from a http.FileSystem.
func fileServer(r chi.Router, path string, root http.FileSystem) {
	if strings.ContainsAny(path, "{}*") {
		panic("FileServer does not permit any URL parameters.")
	}

	if path != "/" && path[len(path)-1] != '/' {
		r.Get(path, http.RedirectHandler(path+"/", 301).ServeHTTP)
		path += "/"
	}
	path += "*"

	r.Get(path, func(w http.ResponseWriter, r *http.Request) {
		rctx := chi.RouteContext(r.Context())
		pathPrefix := strings.TrimSuffix(rctx.RoutePattern(), "/*")
		fs := http.StripPrefix(pathPrefix, http.FileServer(root))
		fs.ServeHTTP(w, r)
	})
}

func main() {
	// Our graceful valve shut-off package to manage code preemption and
	// shutdown signaling.
	vv := valve.New()
	baseCtx := vv.Context()
	configFile := flag.String("config", "", "path to config file")
	envPrefix := os.Getenv("ENV_PREFIX")
	if envPrefix == "" {
		envPrefix = "app"
	}
	flag.Parse()

	cfg, err := app.LoadConfig(*configFile, envPrefix)
	if err != nil {
		log.Fatal(err)
	}

	r := app.Router(baseCtx, cfg)
	workDir, _ := os.Getwd()
	public := http.Dir(filepath.Join(workDir, "./", "public", "assets"))
	fileServer(r, "/static", public)

	srv := &http.Server{
		ReadTimeout:  time.Duration(cfg.ReadTimeoutSecs) * time.Second,
		WriteTimeout: time.Duration(cfg.WriteTimeoutSecs) * time.Second,
		Addr:         fmt.Sprintf(":%d", cfg.Port),
		Handler:      r,
	}

	c := make(chan os.Signal, 1)
	signal.Notify(c, os.Interrupt)
	go func() {
		for range c {
			// sig is a ^C, handle it
			fmt.Println("shutting down..")

			// first valv
			vv.Shutdown(20 * time.Second)

			// create context with timeout
			ctx, cancel := context.WithTimeout(baseCtx, 20*time.Second)
			defer cancel()

			// start http shutdown
			srv.Shutdown(ctx)

			// verify, in worst case call cancel via defer
			select {
			case <-time.After(21 * time.Second):
				fmt.Println("not all connections done")
			case <-ctx.Done():

			}
		}
	}()
	log.Println("http server is listening...")
	srv.ListenAndServe()
}