Add configuration via endpoint and cross compiling scripts

build-linux.sh

@@ -0,0 +1,2 @@
+#! /bin/bash
+env GOOS=linux GOARCH=arm go build

build-mac.sh

@@ -0,0 +1,2 @@
+#! /bin/bash
+env GOOS=darwin GOARCH=386 go build

main.go

@@ -12,6 +12,51 @@ import (
 	"time"
 )
 
+var netClient = &http.Client{
+	Timeout: time.Second * 10,
+}
+
+var mirrors = make(map[string]bool)
+
+func main() {
+	listenPort := flag.String("port", "7071", "Port to listen on")
+	proxyTarget := flag.String("main", "http://localhost:7072", "Main proxy target, its responses will be returned")
+	mirrorsEndpoint := flag.String("mirrors", "mirrors", "Path on which additional mirrors can be added/deleted/listed")
+
+	help := flag.Bool("help", false, "Print help")
+
+	flag.Parse()
+
+	if *help {
+		fmt.Printf("HTTP proxy that:")
+		fmt.Printf("* sends requests to a main endpoint from which the response is returned")
+		fmt.Printf("* can mirror the requests to any additional number of endpoints")
+		fmt.Printf("")
+		fmt.Printf("Additional endpoints are configured via POST/DELETE on the `/mirrors?url=<endpoint>`.")
+
+		flag.PrintDefaults()
+		return
+	}
+
+	url, _ := url.Parse(*proxyTarget)
+
+	proxyTo := httputil.NewSingleHostReverseProxy(url)
+
+	http.HandleFunc("/"+*mirrorsEndpoint, mirrorsHandler)
+
+	http.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
+		body := bufferRequest(req)
+
+		proxyTo.ServeHTTP(res, req)
+		go sendToMirrors(req, body)
+	})
+
+	// start server
+	if err := http.ListenAndServe(":"+*listenPort, nil); err != nil {
+		panic(err)
+	}
+}
+
 func bufferRequest(req *http.Request) []byte {
 	// Read body to buffer
 	body, err := ioutil.ReadAll(req.Body)
@@ -25,8 +70,10 @@ func bufferRequest(req *http.Request) []byte {
 	return body
 }
 
-var netClient = &http.Client{
-	Timeout: time.Second * 10,
+func sendToMirrors(req *http.Request, body []byte) {
+	for mirrorURL := range mirrors {
+		go mirrorTo(mirrorURL, req, body)
+	}
 }
 
 func mirrorTo(targetURL string, req *http.Request, body []byte) {
@@ -43,33 +90,32 @@ func mirrorTo(targetURL string, req *http.Request, body []byte) {
 	defer response.Body.Close()
 }
 
-func main() {
-	listenPort := flag.String("port", "7071", "Port to listen on")
-	proxyTarget := flag.String("main", "http://localhost:7072", "Main proxy target, its responses will be returned")
-	help := flag.Bool("help", false, "Print help")
-
-	flag.Parse()
-
-	if *help {
-		flag.PrintDefaults()
+func mirrorsHandler(res http.ResponseWriter, req *http.Request) {
+	if req.Method == http.MethodGet {
+		for url := range mirrors {
+			fmt.Fprintln(res, url)
+		}
 		return
 	}
 
-	url, _ := url.Parse(*proxyTarget)
-
-	mirrorURL := "http://localhost:7073"
-
-	proxyTo := httputil.NewSingleHostReverseProxy(url)
+	req.ParseForm()
 
-	http.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
-		body := bufferRequest(req)
+	mirrorURLs, inForm := req.Form["url"]
 
-		proxyTo.ServeHTTP(res, req)
-		go mirrorTo(mirrorURL, req, body)
-	})
+	if !inForm {
+		http.Error(res, "Missing required field: 'url'.", http.StatusBadRequest)
+		return
+	}
 
-	// start server
-	if err := http.ListenAndServe(":"+*listenPort, nil); err != nil {
-		panic(err)
+	if req.Method == http.MethodPost {
+		log.Printf("Adding '%s' to mirror list.", mirrorURLs)
+		for _, url := range mirrorURLs {
+			mirrors[url] = true
+		}
+	} else if req.Method == http.MethodDelete {
+		log.Printf("Removing '%s' from mirror list.", mirrorURLs)
+		for _, url := range mirrorURLs {
+			delete(mirrors, url)
+		}
 	}
 }