Add support for requesting ngrok remote address (#436)

README.md

@@ -66,6 +66,8 @@ Routes Minecraft client connections to backend servers based upon the requested
     	any extra tags to be included with all reported metrics (env METRICS_BACKEND_CONFIG_INFLUXDB_TAGS)
   -metrics-backend-config-influxdb-username string
     	 (env METRICS_BACKEND_CONFIG_INFLUXDB_USERNAME)
+  -ngrok-remote-addr string
+    	If set, the TCP address to request for this edge (env NGROK_REMOTE_ADDR)
   -ngrok-token string
     	If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable. (env NGROK_TOKEN)
   -port port
@@ -353,6 +355,16 @@ metadata:
   name: mc-forge
 spec:
   serviceName: mc-forge
+  selector:
+    matchLabels:
+      app: mc-forge
+  template:
+    metadata:
+      labels:
+        app: mc-forge
+    spec:
+      containers:
+        - name: mc
 ```
 
 ## REST API

server/configs.go

@@ -17,6 +17,11 @@ type RoutesConfig struct {
 	ConfigWatch bool   `usage:"Watch for config file changes"`
 }
 
+type NgrokConfig struct {
+	Token      string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
+	RemoteAddr string `usage:"If set, the TCP address to request for this edge"`
+}
+
 type Config struct {
 	Port                  int               `default:"25565" usage:"The [port] bound to listen for Minecraft client connections"`
 	Default               string            `usage:"host:port of a default Minecraft server to use when mapping not found"`
@@ -39,7 +44,7 @@ type Config struct {
 	TrustedProxies        []string `usage:"Comma delimited list of CIDR notation IP blocks to trust when receiving PROXY protocol"`
 	RecordLogins          bool     `default:"false" usage:"Log and generate metrics on player logins. Metrics only supported with influxdb or prometheus backend"`
 	Routes                RoutesConfig
-	NgrokToken            string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
+	Ngrok                 NgrokConfig
 	AutoScale             AutoScale
 
 	ClientsToAllow []string `usage:"Zero or more client IP addresses or CIDRs to allow. Takes precedence over deny."`

server/connector.go

@@ -80,6 +80,11 @@ func NewConnector(ctx context.Context, metrics *ConnectorMetrics, sendProxyProto
 	}
 }
 
+type NgrokConnector struct {
+	token      string
+	remoteAddr string
+}
+
 type Connector struct {
 	ctx                        context.Context
 	state                      mcproto.State
@@ -91,7 +96,7 @@ type Connector struct {
 	totalActiveConnections     int32
 	activeConnections          *ActiveConnections
 	connectionsCond            *sync.Cond
-	ngrokToken                 string
+	ngrok                      NgrokConnector
 	clientFilter               *ClientFilter
 	autoScaleUpAllowDenyConfig *AllowDenyConfig
 	connectionNotifier         ConnectionNotifier
@@ -117,10 +122,12 @@ func (c *Connector) StartAcceptingConnections(listenAddress string, connRateLimi
 }
 
 func (c *Connector) createListener(listenAddress string) (net.Listener, error) {
-	if c.ngrokToken != "" {
+	if c.ngrok.token != "" {
 		ngrokTun, err := ngrok.Listen(c.ctx,
-			config.TCPEndpoint(),
+			config.TCPEndpoint(
-			ngrok.WithAuthtoken(c.ngrokToken),
+				config.WithRemoteAddr(c.ngrok.remoteAddr),
+			),
+			ngrok.WithAuthtoken(c.ngrok.token),
 		)
 		if err != nil {
 			logrus.WithError(err).Fatal("Unable to start ngrok tunnel")
@@ -608,8 +615,9 @@ func (c *Connector) pumpFrames(incoming io.Reader, outgoing io.Writer, errors ch
 	}
 }
 
-func (c *Connector) UseNgrok(token string) {
+func (c *Connector) UseNgrok(config NgrokConfig) {
-	c.ngrokToken = token
+	c.ngrok.token = config.Token
+	c.ngrok.remoteAddr = config.RemoteAddr
 }
 
 func (c *Connector) UseReceiveProxyProto(trustedProxyNets []*net.IPNet) {

server/server.go

@@ -99,8 +99,8 @@ func NewServer(ctx context.Context, config *Config) (*Server, error) {
 			NewWebhookNotifier(config.Webhook.Url, config.Webhook.RequireUser))
 	}
 
-	if config.NgrokToken != "" {
+	if config.Ngrok.Token != "" {
-		connector.UseNgrok(config.NgrokToken)
+		connector.UseNgrok(config.Ngrok)
 	}
 
 	if config.ReceiveProxyProtocol {