CTL: JSON output

ctl/format.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
+	"os"
 	"strconv"
 
 	"github.com/rosti-cz/server_lobby/server"
@@ -41,3 +43,13 @@ func printDiscoveries(discoveries []server.Discovery) {
 		fmt.Println()
 	}
 }
+
+func printJSON(data interface{}) {
+	body, err := json.Marshal(data)
+	if err != nil {
+		fmt.Println("error occurred while formating the output into JSON:", err.Error())
+		os.Exit(3)
+	}
+
+	fmt.Println(string(body))
+}

ctl/main.go

@@ -30,6 +30,7 @@ func main() {
 	host := flag.String("host", "", "Hostname or IP address of lobby daemon")
 	port := flag.Uint("port", 0, "Port of lobby daemon")
 	token := flag.String("token", "", "Token needed to communicate lobby daemon, if empty auth is disabled")
+	jsonOutput := flag.Bool("json", false, "set output to JSON, error will be still in plain text")
 
 	flag.Parse()
 
@@ -103,13 +104,22 @@ func main() {
 			}
 		}
 
-		printDiscoveries(discoveries)
+		if *jsonOutput {
+			printJSON(discoveries)
+		} else {
+			printDiscoveries(discoveries)
+		}
 	case "discovery":
 		discovery, err := client.GetDiscovery()
 		if err != nil {
 			fmt.Println(err)
 		}
-		printDiscovery(discovery)
+
+		if *jsonOutput {
+			printJSON(discovery)
+		} else {
+			printDiscovery(discovery)
+		}
 	case "labels":
 		if len(flag.Args()) < 3 {
 			fmt.Println("ERROR: not enough arguments for labels command")