feat(cmd): main entrypoint and config loader

cmd/ezcoo-usb-control/config.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"gopkg.in/yaml.v3"
+
+	"gitea.berezovskyi.dev/oleksandr/ezcoo-usb-control/pkg/bridge"
+	"gitea.berezovskyi.dev/oleksandr/ezcoo-usb-control/pkg/ezcoo"
+)
+
+type appConfig struct {
+	Device ezcoo.Config  `yaml:"device"`
+	MQTT   bridge.Config `yaml:"mqtt"`
+}
+
+func (c *appConfig) SetDefaults() {
+	c.Device.SetDefaults()
+	c.MQTT.SetDefaults()
+}
+
+func (c *appConfig) Validate() error {
+	if err := c.Device.Validate(); err != nil {
+		return err
+	}
+	return c.MQTT.Validate()
+}
+
+func loadConfig(path string) (appConfig, error) {
+	var cfg appConfig
+	if path != "" {
+		f, err := os.Open(path)
+		if err != nil {
+			return cfg, fmt.Errorf("open config: %w", err)
+		}
+		defer f.Close()
+		if err := yaml.NewDecoder(f).Decode(&cfg); err != nil {
+			return cfg, fmt.Errorf("parse config: %w", err)
+		}
+	}
+	cfg.SetDefaults()
+	if err := cfg.Validate(); err != nil {
+		return cfg, fmt.Errorf("validate config: %w", err)
+	}
+	return cfg, nil
+}