http_{server,proxy}: support multiple ports binding

Fixes #629

bind/flag.go

@@ -239,9 +239,10 @@ func HTTPServerConfig(fs *pflag.FlagSet, cfg *forwarder.HTTPServerConfig, prefix
 		namePrefix += "-"
 	}
 
-	fs.StringVarP(&cfg.Addr,
-		namePrefix+"address", "", cfg.Addr, "<host:port>"+
+	fs.VarP(anyflag.NewValue[forwarder.MultiplePortsAddr](cfg.Addr, &cfg.Addr, forwarder.ParseMultiplePortsAddr),
+		namePrefix+"address", "", "[host]:<port,...>"+
 			"The server address to listen on. "+
+			"Multiple ports can be specified separated by commas. "+
 			"If the host is empty, the server will listen on all available interfaces. ")
 
 	if schemes == nil {

command/run/run.go

@@ -224,7 +224,7 @@ func (c *command) runE(cmd *cobra.Command, _ []string) (cmdErr error) {
 		}
 	}
 
-	if c.apiServerConfig.Addr != "" {
+	if !c.apiServerConfig.Addr.IsZero() {
 		if err := c.registerProcMetrics(); err != nil {
 			return fmt.Errorf("register process metrics: %w", err)
 		}
@@ -317,7 +317,10 @@ func Command() *cobra.Command {
 	}
 	c.httpProxyConfig.PromRegistry = c.promReg
 	c.httpProxyConfig.PromNamespace = promNs
-	c.apiServerConfig.Addr = "localhost:10000"
+	c.apiServerConfig.Addr = forwarder.MultiplePortsAddr{
+		Host:  "localhost",
+		Ports: []string{"10000"},
+	}
 
 	cmd := &cobra.Command{
 		Use:     "run [--address <host:port>] [--pac <path or url>] [--credentials <username:password@host:port>]...",

command/test/httpbin/httpbin.go

@@ -84,7 +84,10 @@ func Command() *cobra.Command {
 		apiServerConfig:  forwarder.DefaultHTTPServerConfig(),
 		logConfig:        log.DefaultConfig(),
 	}
-	c.apiServerConfig.Addr = "localhost:10000"
+	c.apiServerConfig.Addr = forwarder.MultiplePortsAddr{
+		Host:  "localhost",
+		Ports: []string{"10000"},
+	}
 
 	cmd := &cobra.Command{
 		Use:   "httpbin [--protocol <http|https|h2>] [--address <host:port>] [flags]",

http_proxy.go

@@ -105,8 +105,10 @@ type HTTPProxyConfig struct {
 func DefaultHTTPProxyConfig() *HTTPProxyConfig {
 	return &HTTPProxyConfig{
 		HTTPServerConfig: HTTPServerConfig{
-			Protocol:          HTTPScheme,
-			Addr:              ":3128",
+			Protocol: HTTPScheme,
+			Addr: MultiplePortsAddr{
+				Ports: []string{"3128"},
+			},
 			ReadHeaderTimeout: 1 * time.Minute,
 			TLSServerConfig: TLSServerConfig{
 				HandshakeTimeout: 10 * time.Second,
@@ -609,8 +611,13 @@ func (hp *HTTPProxy) listen() (net.Listener, error) {
 		return nil, fmt.Errorf("invalid protocol %q", hp.config.Protocol)
 	}
 
+	addrs := make([]string, 0, len(hp.config.Addr.Ports))
+	for _, port := range hp.config.Addr.Ports {
+		addrs = append(addrs, net.JoinHostPort(hp.config.Addr.Host, port))
+	}
+
 	l := Listener{
-		Addresses:           []string{hp.config.Addr},
+		Addresses:           addrs,
 		Log:                 hp.log,
 		TLSConfig:           hp.tlsConfig,
 		TLSHandshakeTimeout: hp.config.TLSServerConfig.HandshakeTimeout,

http_server.go

@@ -14,6 +14,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"strings"
 	"sync"
 	"time"
 
@@ -73,9 +74,30 @@ func h2TLSConfigTemplate() *tls.Config {
 	}
 }
 
+type MultiplePortsAddr struct {
+	Host  string
+	Ports []string
+}
+
+func ParseMultiplePortsAddr(val string) (MultiplePortsAddr, error) {
+	i := strings.LastIndex(val, ":")
+	if i == -1 || i == len(val)-1 {
+		return MultiplePortsAddr{}, fmt.Errorf("invalid address %q", val)
+	}
+
+	return MultiplePortsAddr{
+		Host:  val[:i],
+		Ports: strings.Split(val[i+1:], ","),
+	}, nil
+}
+
+func (m MultiplePortsAddr) IsZero() bool {
+	return m.Host == "" && len(m.Ports) == 0
+}
+
 type HTTPServerConfig struct {
 	Protocol Scheme
-	Addr     string
+	Addr     MultiplePortsAddr
 	TLSServerConfig
 	IdleTimeout       time.Duration
 	ReadTimeout       time.Duration
@@ -90,8 +112,10 @@ type HTTPServerConfig struct {
 
 func DefaultHTTPServerConfig() *HTTPServerConfig {
 	return &HTTPServerConfig{
-		Protocol:          HTTPScheme,
-		Addr:              ":8080",
+		Protocol: HTTPScheme,
+		Addr: MultiplePortsAddr{
+			Ports: []string{"8080"},
+		},
 		ReadHeaderTimeout: 1 * time.Minute,
 	}
 }
@@ -121,7 +145,6 @@ func NewHTTPServer(cfg *HTTPServerConfig, h http.Handler, log log.Logger) (*HTTP
 		config: *cfg,
 		log:    log,
 		srv: &http.Server{
-			Addr:              cfg.Addr,
 			Handler:           withMiddleware(cfg, log, h),
 			IdleTimeout:       cfg.IdleTimeout,
 			ReadTimeout:       cfg.ReadTimeout,
@@ -230,8 +253,13 @@ func (hs *HTTPServer) Run(ctx context.Context) error {
 }
 
 func (hs *HTTPServer) listen() (net.Listener, error) {
+	addrs := make([]string, 0, len(hs.config.Addr.Ports))
+	for _, port := range hs.config.Addr.Ports {
+		addrs = append(addrs, net.JoinHostPort(hs.config.Addr.Host, port))
+	}
+
 	l := Listener{
-		Addresses:           []string{hs.config.Addr},
+		Addresses:           addrs,
 		Log:                 hs.log,
 		TLSConfig:           hs.srv.TLSConfig,
 		TLSHandshakeTimeout: hs.config.HandshakeTimeout,