From 716f4c5cf7c1119d8dfa884448546d272aa3c457 Mon Sep 17 00:00:00 2001
From: Dimitri Herzog <dimitri.herzog@gmail.com>
Date: Mon, 20 Apr 2020 17:05:28 +0200
Subject: [PATCH] configuration for request throttling

---
 consts/consts.go | 3 +++
 server/server.go | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/consts/consts.go b/consts/consts.go
index 51d691a2..1dfa8e70 100644
--- a/consts/consts.go
+++ b/consts/consts.go
@@ -26,6 +26,9 @@ const (
 
 	URLPathUI          = "/app"
 	URLPathSubsonicAPI = "/rest"
+
+	RequestThrottleBacklogLimit   = 100
+	RequestThrottleBacklogTimeout = time.Minute
 )
 
 // Cache options
diff --git a/server/server.go b/server/server.go
index 6b7e5f9c..0c98a855 100644
--- a/server/server.go
+++ b/server/server.go
@@ -1,10 +1,12 @@
 package server
 
 import (
+	"math"
 	"net/http"
 	"os"
 	"path"
 	"path/filepath"
+	"runtime"
 	"time"
 
 	"github.com/deluan/navidrome/conf"
@@ -62,6 +64,10 @@ func (a *Server) initRoutes() {
 	r.Use(middleware.Heartbeat("/ping"))
 	r.Use(InjectLogger)
 
+	// configure request throttling
+	maxRequests := math.Max(2, float64(runtime.NumCPU()))
+	r.Use(middleware.ThrottleBacklog(int(maxRequests), consts.RequestThrottleBacklogLimit, consts.RequestThrottleBacklogTimeout))
+
 	indexHtml := path.Join(conf.Server.BaseURL, consts.URLPathUI, "index.html")
 	r.Get("/*", func(w http.ResponseWriter, r *http.Request) {
 		http.Redirect(w, r, indexHtml, 302)