From 0c6e174d82c245429301c9412e6a5d76fccc93d0 Mon Sep 17 00:00:00 2001
From: Mikalai Konan <mikalai.konan@icloud.com>
Date: Fri, 31 Dec 2021 15:43:45 +0300
Subject: [PATCH] configurable concurrency limit

---
 main.go         |  5 +++--
 proxy/config.go |  7 +++++--
 proxy/router.go | 19 +++++++++++--------
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/main.go b/main.go
index 2cc8c78..af6471a 100644
--- a/main.go
+++ b/main.go
@@ -43,8 +43,9 @@ func newApp() *app {
 			KucoinApiURL:      "https://openapi-v2.kucoin.com",
 		},
 		ProxyConfig: proxy.Config{
-			Port:     "8080",
-			Bindaddr: "0.0.0.0",
+			Port:             "8080",
+			Bindaddr:         "0.0.0.0",
+			ConcurrencyLimit: fasthttp.DefaultConcurrency,
 		},
 	}
 }
diff --git a/proxy/config.go b/proxy/config.go
index c2caf78..674f4fc 100644
--- a/proxy/config.go
+++ b/proxy/config.go
@@ -3,16 +3,19 @@ package proxy
 import (
 	validation "github.com/go-ozzo/ozzo-validation/v4"
 	"github.com/go-ozzo/ozzo-validation/v4/is"
+	"github.com/valyala/fasthttp"
 )
 
 type Config struct {
-	Port     string `help:"listen port"`
-	Bindaddr string `help:"bindable address"`
+	Port             string `help:"listen port"`
+	Bindaddr         string `help:"bindable address"`
+	ConcurrencyLimit int    `help:"server concurrency limit"`
 }
 
 func (c Config) Validate() error {
 	return validation.ValidateStruct(&c,
 		validation.Field(&c.Port, is.Port),
 		validation.Field(&c.Bindaddr, is.IPv4),
+		validation.Field(&c.ConcurrencyLimit, validation.Min(fasthttp.DefaultConcurrency)),
 	)
 }
diff --git a/proxy/router.go b/proxy/router.go
index 149f85b..082d2ee 100644
--- a/proxy/router.go
+++ b/proxy/router.go
@@ -20,7 +20,7 @@ type Routable interface {
 	Name() string
 }
 
-func New(config *Config, routable Routable) *Router {
+func New(config *Config, routable Routable) *Server {
 	router := routing.New()
 
 	for _, route := range routable.Routes() {
@@ -35,18 +35,21 @@ func New(config *Config, routable Routable) *Router {
 		router.To(route.Method, path, route.Handler)
 	}
 
-	return &Router{
-		router: router,
+	return &Server{
+		server: &fasthttp.Server{
+			Handler:     router.HandleRequest,
+			Concurrency: config.ConcurrencyLimit,
+		},
 		config: config,
 	}
 }
 
-type Router struct {
+type Server struct {
 	config *Config
-	router *routing.Router
+	server *fasthttp.Server
 }
 
-func (r *Router) Serve() {
-	logrus.Infof("starting proxy server on :%s port...", r.config.Port)
-	panic(fasthttp.ListenAndServe(fmt.Sprintf("%s:%s", r.config.Bindaddr, r.config.Port), r.router.HandleRequest))
+func (s *Server) Serve() {
+	logrus.Infof("starting proxy server on :%s port...", s.config.Port)
+	logrus.Fatal(s.server.ListenAndServe(fmt.Sprintf("%s:%s", s.config.Bindaddr, s.config.Port)))
 }