config: add load/save config file

cmd/kvm/main.go

@@ -12,8 +12,16 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+const ConfigFile = "/etc/rkkvm/rkkvm.yml"
+
 func main() {
-	config.Init()
+	if err := config.Load(ConfigFile); err != nil {
+		config.Init()
+		if err = config.Save(ConfigFile); err != nil {
+			log.Error(err)
+		}
+	}
+
 	cfg := config.Get()
 	lvl, err := log.ParseLevel(cfg.LogLevel)
 	if err == nil {

config/config.go

@@ -2,7 +2,10 @@ package config
 
 import (
 	"fmt"
+	"os"
 	"strings"
+
+	"gopkg.in/yaml.v3"
 )
 
 type Config struct {
@@ -107,3 +110,34 @@ func Init() {
 		NanoKVMUISupport: true,
 	}
 }
+
+func Load(fname string) error {
+	yamlData, err := os.ReadFile(fname)
+	if err != nil {
+		return fmt.Errorf("config: couldn't read config file: %w", err)
+	}
+
+	var cfg Config
+	err = yaml.Unmarshal(yamlData, &cfg)
+	if err != nil {
+		return fmt.Errorf("config: couldn't parse config file: %w", err)
+	}
+
+	c = cfg
+
+	return nil
+}
+
+func Save(fname string) error {
+	data, err := yaml.Marshal(c)
+	if err != nil {
+		return fmt.Errorf("config: failed to marshal config: %w", err)
+	}
+
+	err = os.WriteFile(fname, data, 0o660)
+	if err != nil {
+		return fmt.Errorf("config: failed to write config: %w", err)
+	}
+
+	return nil
+}

docker-compose.yml

@@ -8,6 +8,7 @@ services:
       - /sys/kernel/config:/sys/kernel/config
       - ./test_data:/data
       - /dev:/dev # required, if you will use Mass-Storage-Device
+      - ./test_data/config:/etc/rkkvm
     #devices:
       #- /dev/hidg0
       #- /dev/hidg1