reuseport option

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/dop251/goja v0.0.0-20241024094426-79f3a7efcdbd
 	github.com/hashicorp/go-multierror v1.1.1
 	github.com/jellydator/ttlcache/v3 v3.3.0
+	github.com/libp2p/go-reuseport v0.4.0
 	github.com/tg123/go-htpasswd v1.2.3
 	github.com/zeebo/xxh3 v1.0.2
 	golang.org/x/crypto v0.31.0

go.sum

@@ -24,6 +24,8 @@ github.com/jellydator/ttlcache/v3 v3.3.0 h1:BdoC9cE81qXfrxeb9eoJi9dWrdhSuwXMAnHT
 github.com/jellydator/ttlcache/v3 v3.3.0/go.mod h1:bj2/e0l4jRnQdrnSTaGTsh4GSXvMjQcy41i7th0GVGw=
 github.com/klauspost/cpuid/v2 v2.2.9 h1:66ze0taIn2H33fBvCkXuv9BmCwDfafmiIVpKV9kKGuY=
 github.com/klauspost/cpuid/v2 v2.2.9/go.mod h1:rqkxqrZ1EhYM9G+hXH7YdowN5R5RGN6NK4QwQ3WMXF8=
+github.com/libp2p/go-reuseport v0.4.0 h1:nR5KU7hD0WxXCJbmw7r2rhRYruNRl2koHw8fQscQm2s=
+github.com/libp2p/go-reuseport v0.4.0/go.mod h1:ZtI03j/wO5hZVDFo2jKywN6bYKWLOy8Se6DrI2E1cLU=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=

main.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/coreos/go-systemd/v22/activation"
+	"github.com/libp2p/go-reuseport"
 	"golang.org/x/crypto/acme"
 	"golang.org/x/crypto/acme/autocert"
 	"golang.org/x/crypto/bcrypt"
@@ -176,6 +177,7 @@ type proxyArg struct {
 
 type CLIArgs struct {
 	bind_address            string
+	bind_reuseport          bool
 	auth                    string
 	verbosity               int
 	cert, key, cafile       string
@@ -229,6 +231,7 @@ func parse_args() CLIArgs {
 		},
 	}
 	flag.StringVar(&args.bind_address, "bind-address", ":8080", "HTTP proxy listen address. Set empty value to use systemd socket activation.")
+	flag.BoolVar(&args.bind_reuseport, "bind-reuseport", false, "allow multiple server instances on the same port")
 	flag.StringVar(&args.auth, "auth", "none://", "auth parameters")
 	flag.IntVar(&args.verbosity, "verbosity", 20, "logging verbosity "+
 		"(10 - debug, 20 - info, 30 - warning, 40 - error, 50 - critical)")
@@ -470,7 +473,15 @@ func run() int {
 		}
 		listener = listeners[0]
 	} else {
-		newListener, err := net.Listen("tcp", args.bind_address)
+		listenerFactory := net.Listen
+		if args.bind_reuseport {
+			if reuseport.Available() {
+				listenerFactory = reuseport.Listen
+			} else {
+				mainLogger.Warning("reuseport was requested but not available!")
+			}
+		}
+		newListener, err := listenerFactory("tcp", args.bind_address)
 		if err != nil {
 			mainLogger.Critical("listen failed: %v", err)
 			return 3