Add 404-server (defaultbackend)

images/404-server/server.go

@@ -0,0 +1,66 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// A webserver that only serves a 404 page. Used as a default backend.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+var port = flag.Int("port", 8080, "Port number to serve default backend 404 page.")
+
+func init() {
+	// Register the summary and the histogram with Prometheus's default registry.
+	prometheus.MustRegister(requestCount)
+	prometheus.MustRegister(requestDuration)
+}
+
+func main() {
+	flag.Parse()
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		start := time.Now()
+		w.WriteHeader(http.StatusNotFound)
+		fmt.Fprint(w, "default backend - 404")
+
+		duration := time.Now().Sub(start).Seconds() * 1e3
+
+		proto := strconv.Itoa(r.ProtoMajor)
+		proto = proto + "." + strconv.Itoa(r.ProtoMinor)
+
+		requestCount.WithLabelValues(proto).Inc()
+		requestDuration.WithLabelValues(proto).Observe(duration)
+	})
+	http.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprint(w, "ok")
+	})
+	http.Handle("/metrics", promhttp.Handler())
+	// TODO: Use .Shutdown from Go 1.8
+	err := http.ListenAndServe(fmt.Sprintf(":%d", *port), nil)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "could not start http server: %s\n", err)
+		os.Exit(1)
+	}
+}