HH-738: add constrained browser container control (#4)

cmd/control-plane/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"log"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+func main() {
+	gateway, err := url.Parse(env("DOCKER_GATEWAY_URL", "http://127.0.0.1:8081"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(gateway)
+	originalDirector := proxy.Director
+	proxy.Director = func(request *http.Request) {
+		originalDirector(request)
+		request.URL.Path = "/v1/browsers" + strings.TrimPrefix(request.URL.Path, "/api/browsers")
+		request.Host = gateway.Host
+	}
+
+	mux := http.NewServeMux()
+	mux.Handle("/api/browsers", proxy)
+	mux.Handle("/api/browsers/", proxy)
+	mux.HandleFunc("GET /healthz", func(response http.ResponseWriter, _ *http.Request) {
+		response.WriteHeader(http.StatusNoContent)
+	})
+	mux.Handle("/", spaHandler(env("WEB_DIR", "web/dist")))
+
+	server := &http.Server{
+		Addr:              env("LISTEN_ADDR", ":8080"),
+		Handler:           mux,
+		ReadHeaderTimeout: 5 * time.Second,
+		IdleTimeout:       60 * time.Second,
+	}
+	log.Printf("CreatorHub control plane listening on %s", server.Addr)
+	log.Fatal(server.ListenAndServe())
+}
+
+func spaHandler(directory string) http.Handler {
+	files := http.FileServer(http.Dir(directory))
+	return http.HandlerFunc(func(response http.ResponseWriter, request *http.Request) {
+		name := filepath.Join(directory, filepath.Clean(strings.TrimPrefix(request.URL.Path, "/")))
+		if info, err := os.Stat(name); err == nil && !info.IsDir() {
+			files.ServeHTTP(response, request)
+			return
+		}
+		http.ServeFile(response, request, filepath.Join(directory, "index.html"))
+	})
+}
+
+func env(name, fallback string) string {
+	if value := os.Getenv(name); value != "" {
+		return value
+	}
+	return fallback
+}