Bring back the queue.

pkg/controller/revision/ela_nginx_constants.go

@@ -50,11 +50,7 @@ http {
   # to avoid a race condition between the two timeouts.
   keepalive_timeout 650;
   keepalive_requests 10000;
-{{if .EnableQueue}}
   upstream queue { server 127.0.0.1:8012; }
-{{else}}
-  upstream app_server { keepalive 64; server 127.0.0.1:8080; }
-{{end}}
 
   geo $source_type {
     default ext;

pkg/sidecars/queue/Dockerfile

@@ -0,0 +1,4 @@
+FROM ubuntu:latest
+ADD queue /
+ENTRYPOINT ["/queue"]
+EXPOSE 8012

pkg/sidecars/queue/queue.go

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"time"
+)
+
+type request struct {
+	w http.ResponseWriter
+	r *http.Request
+	c chan struct{}
+}
+
+var requestChan = make(chan *request)
+
+func init() { log.Println("Init queue container.") }
+func consumer() {
+	target, err := url.Parse("http://127.0.0.1:8080")
+	if err != nil {
+		panic(err)
+	}
+	proxy := httputil.NewSingleHostReverseProxy(target)
+	for {
+		r := <-requestChan
+		log.Println("Forwarding a request to the app container at ", time.Now().String())
+		proxy.ServeHTTP(r.w, r.r)
+		close(r.c)
+	}
+}
+func handler(w http.ResponseWriter, r *http.Request) {
+	req := &request{
+		w: w,
+		r: r,
+		c: make(chan struct{}),
+	}
+	log.Println("Adding a request to the the request channel at ", time.Now().String())
+	requestChan <- req
+	<-req.c
+}
+func main() {
+	log.Println("Queue container is running")
+	go consumer()
+	http.HandleFunc("/", handler)
+	http.ListenAndServe(":8012", nil)
+}