add example

httputil/examples/server_example.go

@@ -0,0 +1,106 @@
+// Example program using kit/httputil to launch a web server. Content
+// is served via https, with a redirect on http. It uses autocert to
+// fetch a letsencrypt cert (from staging).
+package main
+
+import (
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/kolide/kit/httputil"
+	"github.com/oklog/run"
+	"golang.org/x/crypto/acme/autocert"
+)
+
+func main() {
+
+	var (
+		flHostName = flag.String("hostname", "", "External hostname for service. Needed for autocert")
+		flCertDir  = flag.String("certdir", "", "Directory to store certificates in")
+	)
+	flag.Parse()
+
+	if *flHostName == "" {
+		fmt.Println("Must specify hostname")
+		os.Exit(1)
+	}
+
+	if *flCertDir == "" {
+		fmt.Println("Must specify certdir")
+		os.Exit(1)
+	}
+
+	m, err := httputil.NewAutocertManager(
+		autocert.DirCache(*flCertDir),
+		[]string{*flHostName},
+		httputil.WithLetsEncryptStaging(),
+	)
+	if err != nil {
+		panic(err)
+	}
+
+	var g run.Group
+	{
+		srv := httputil.NewServer(
+			":443",
+			stringMiddleware("secure!", nil),
+			httputil.WithTLSConfig(&tls.Config{GetCertificate: m.GetCertificate}),
+		)
+
+		g.Add(func() error {
+			fmt.Println("Starting port 443")
+			return srv.ListenAndServeTLS("", "")
+		}, func(err error) {
+			srv.Close()
+			return
+		})
+	}
+	{
+		srv := httputil.NewServer(
+			":80",
+			m.HTTPHandler(httputil.RedirectToSecureHandler()),
+			httputil.WithReadTimeout(5*time.Second),
+			httputil.WithWriteTimeout(5*time.Second),
+		)
+
+		g.Add(func() error {
+			fmt.Println("Starting port 80")
+			return srv.ListenAndServe()
+		}, func(err error) {
+			srv.Close()
+			return
+		})
+	}
+
+	{
+		// this actor handles an os interrupt signal and terminates the server.
+		sig := make(chan os.Signal, 1)
+		g.Add(func() error {
+			signal.Notify(sig, os.Interrupt)
+			<-sig
+			fmt.Println("beginning shutdown")
+			return nil
+		}, func(err error) {
+			fmt.Println("process interrupted")
+			close(sig)
+		})
+	}
+
+	if err := g.Run(); err != nil {
+		panic(err)
+	}
+}
+
+func stringMiddleware(s string, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, s)
+		if next != nil {
+			next.ServeHTTP(w, r)
+		}
+	})
+}