fix ip protocol detection: RemoteAddr is host:port

fe/http.go

@@ -122,8 +122,11 @@ func NewHTTPRedirector(client *autoradio.Client, domain, lbspec, staticDir, temp
 // Pick a random IP with a protocol appropriate to the request (based
 // on the remote address).
 func randomIPForRequest(ips []net.IP, r *http.Request) net.IP {
-	remoteAddr := net.ParseIP(r.RemoteAddr)
-	isV6 := (remoteAddr != nil && (remoteAddr.To4() == nil))
+	isV6 := false
+	if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
+		remoteAddr := net.ParseIP(host)
+		isV6 = (remoteAddr != nil && (remoteAddr.To4() == nil))
+	}
 	return randomIPByProto(ips, isV6)
 }
 
@@ -145,6 +148,8 @@ func (h *HTTPRedirector) pickActiveNode(r *http.Request) net.IP {
 	return randomIPForRequest(result.IP, r)
 }
 
+// Periodically update the active nodes information in the load
+// balancer. Requests will then use the cached data.
 func (h *HTTPRedirector) lbUpdater() {
 	for range time.NewTicker(2 * time.Second).C {
 		nodes, err := h.client.GetNodes()