recover gracefully if no server found

README.md

@@ -17,6 +17,8 @@ Execute `mullvad-best-server`. It outputs the code, e.g. `de05`. You can then co
 Usage of dist/mullvad-best-server_darwin_amd64/mullvad-best-server:
 -c string
   Server country code, e.g. ch for Switzerland (default "ch")
+-l string
+  Log level. Allowed values: trace, debug, info, warn, error, fatal, panic (default "info")
 -o string
   Output format. 'json' outputs server json
 -t string

main.go

@@ -29,6 +29,9 @@ func main() {
 	zerolog.SetGlobalLevel(level)
 	servers := getServers(*typeFlag)
 	bestIndex := selectBestServerIndex(servers, *countryFlag)
+	if bestIndex == -1 {
+		log.Fatal().Str("country", *countryFlag).Msg("No servers for country found.")
+	}
 	best := servers[bestIndex]
 	log.Debug().Interface("server", best).Msg("Best latency server found.")
 	hostname := strings.TrimSuffix(best.Hostname, "-wireguard")