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

@@ -16,14 +16,22 @@ import (
 )
 
 func main() {
-	zerolog.SetGlobalLevel(zerolog.InfoLevel)
 	var outputFlag = flag.String("o", "", "Output format. 'json' outputs server json")
 	var countryFlag = flag.String("c", "ch", "Server country code, e.g. ch for Switzerland")
 	var typeFlag = flag.String("t", "wireguard", "Server type, e.g. wireguard")
+	var logLevel = flag.String("l", "info", "Log level. Allowed values: trace, debug, info, warn, error, fatal, panic")
 	flag.Parse()
 
+	level, err := zerolog.ParseLevel(*logLevel)
+	if err != nil {
+		log.Fatal().Err(err).Msg("Unable to set log level")
+	}
+	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")