feat: print a message when hello service is stopped via signal

hello.go

@@ -3,6 +3,9 @@ package vproxy
 import (
 	"fmt"
 	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
 )
 
 // StartHello world service on the given host/port
@@ -11,6 +14,20 @@ import (
 // It's mainly here to serve as a simple demo of vproxy's abilities (see readme).
 func StartHello(host string, port int) error {
 	fmt.Printf("~> starting vproxy hello service at http://%s:%d\n", host, port)
+
+	// trap signals so we can print before exiting
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM, syscall.SIGHUP)
+	go func() {
+		// catch ^c, cleanup
+		s := <-c
+		if s == nil {
+			return
+		}
+		fmt.Println("~> caught signal:", s)
+		os.Exit(0)
+	}()
+
 	return http.ListenAndServe(fmt.Sprintf("%s:%d", host, port), http.HandlerFunc(helloHandler))
 }