Add listen-domains

- add listen-domains config key
- add method to fetch domains list to listen

Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>

cmd/gate/app-settings.go

@@ -75,6 +75,7 @@ const ( // settings
 	cfgEnableMetrics  = "metrics"
 	cfgEnableProfiler = "pprof"
 	cfgListenAddress  = "listen_address"
+	cfgListenDomains  = "listen_domains"
 
 	// Peers
 	cfgPeers = "peers"
@@ -127,6 +128,21 @@ func fetchPeers(l *zap.Logger, v *viper.Viper) map[string]float64 {
 	return peers
 }
 
+func fetchDomains(v *viper.Viper) []string {
+	cnt := v.GetInt(cfgListenDomains + ".count")
+	res := make([]string, 0, cnt)
+	for i := 0; ; i++ {
+		domain := v.GetString(cfgListenDomains + "." + strconv.Itoa(i))
+		if domain == "" {
+			break
+		}
+
+		res = append(res, domain)
+	}
+
+	return res
+}
+
 func newSettings() *viper.Viper {
 	v := viper.New()
 
@@ -162,6 +178,8 @@ func newSettings() *viper.Viper {
 	flags.String(cfgListenAddress, "0.0.0.0:8080", "set address to listen")
 	peers := flags.StringArrayP(cfgPeers, "p", nil, "set NeoFS nodes")
 
+	domains := flags.StringArrayP(cfgListenDomains, "d", nil, "set domains to be listened")
+
 	// set prefers:
 	v.Set(cfgApplicationName, misc.ApplicationName)
 	v.Set(cfgApplicationVersion, misc.Version)
@@ -203,6 +221,14 @@ func newSettings() *viper.Viper {
 		}
 	}
 
+	if domains != nil && len(*domains) > 0 {
+		for i := range *domains {
+			v.SetDefault(cfgListenDomains+"."+strconv.Itoa(i), (*domains)[i])
+		}
+
+		v.SetDefault(cfgListenDomains+".count", len(*domains))
+	}
+
 	switch {
 	case help != nil && *help:
 		fmt.Printf("NeoFS S3 Gateway %s (%s)\n", misc.Version, misc.Build)

cmd/gate/app.go

@@ -214,7 +214,10 @@ func (a *App) Server(ctx context.Context) {
 	attachProfiler(router, a.cfg, a.log)
 
 	// Attach S3 API:
-	api.Attach(router, a.maxClients, a.api, a.ctr, a.log)
+	domains := fetchDomains(a.cfg)
+	a.log.Info("fetch domains, prepare to use API",
+		zap.Strings("domains", domains))
+	api.Attach(router, domains, a.maxClients, a.api, a.ctr, a.log)
 
 	// Use mux.Router as http.Handler
 	srv.Handler = router