find the good ip address using lookup

Signed-off-by: Florent Poinsard <florent.poinsard@outlook.fr>

go/config.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"net"
 	"os"
 
 	"github.com/joho/godotenv"
@@ -69,9 +70,16 @@ func readConfig() (*config, error) {
 	// Get server address
 	serverAddress := os.Getenv("SERVER_ADDRESS")
 	if serverAddress == "" {
-		serverAddress, err = os.Hostname()
+		addrs, err := net.InterfaceAddrs()
 		if err != nil {
-			return nil, errors.Wrap(err, "could not resolve hostname")
+			panic(err)
+		}
+
+		for _, addr := range addrs {
+			if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() && ipnet.IP.To4() != nil {
+				serverAddress = ipnet.IP.String()
+				break
+			}
 		}
 	}
 	c.address = serverAddress