More tweaks on web server.

cmd/gqgmcd/main.go

@@ -8,15 +8,23 @@
 package main
 
 import (
+	"flag"
 	"fmt"
+	"log"
 	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
+var addr = flag.String("listen-address", ":8080", "Address for HTTP requests.")
+
 func metricsHandler(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, "Some metrics.")
 }
 
 func main() {
+	flag.Parse()
 	http.HandleFunc("/", metricsHandler)
-	http.ListenAndServe(":8080", nil)
+	http.Handle("/metrics", promhttp.Handler())
+	log.Fatal(http.ListenAndServe(*addr, nil))
 }