feat: smart config

internal/config/admin.go

@@ -0,0 +1,7 @@
+package config
+
+type AdminConfig struct {
+	Name     string `env:"GUARD_ADMIN_NAME" default:"Admin"`
+	Email    string `env:"GUARD_ADMIN_EMAIL" required:"true"`
+	Password string `env:"GUARD_ADMIN_PASSWORD" required:"true"`
+}

internal/config/jwt.go

@@ -0,0 +1,8 @@
+package config
+
+type JwtConfig struct {
+	PrivateKey string `env:"GUARD_JWT_PRIVATE" required:"true"`
+	PublicKey  string `env:"GUARD_JWT_PUBLIC" required:"true"`
+	KID        string `env:"GUARD_JWT_KID" default:"guard-rsa"`
+	Issuer     string `env:"GUARD_JWT_ISSUER" required:"true"`
+}

internal/config/minio.go

@@ -0,0 +1,7 @@
+package config
+
+type MinioConfig struct {
+	Endpoint  string `env:"GUARD_MINIO_ENDPOINT" default:"localhost:9000"`
+	AccessKey string `env:"GUARD_MINIO_ACCESS_KEY" required:"true"`
+	SecretKey string `env:"GUARD_MINIO_SECRET_KEY" required:"true"`
+}

internal/config/mod.go

@@ -0,0 +1,98 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+type AppConfig struct {
+	Port        string `env:"GUARD_PORT" default:"3001"`
+	Host        string `env:"GUARD_HOST" default:"127.0.0.1"`
+	DatabaseURL string `env:"GUARD_DB_URL" required:"true"`
+	Admin       AdminConfig
+	Jwt         JwtConfig
+	Minio       MinioConfig
+}
+
+func LoadEnv(target any) error {
+	v := reflect.ValueOf(target)
+	if v.Kind() != reflect.Pointer || v.Elem().Kind() != reflect.Struct {
+		return &InvalidTargetError{}
+	}
+	return loadStruct(v.Elem(), "")
+}
+
+type InvalidTargetError struct{}
+
+func (e *InvalidTargetError) Error() string {
+	return "target must be a pointer to a struct"
+}
+
+var ErrMissingRequiredEnv = errors.New("missing required environment variable")
+
+func loadStruct(v reflect.Value, prefix string) error {
+	t := v.Type()
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		valueField := v.Field(i)
+
+		if !valueField.CanSet() {
+			continue
+		}
+
+		envKey := field.Tag.Get("env")
+		if envKey == "" {
+			envKey = strings.ToUpper(prefix + "_" + field.Name)
+			envKey = strings.TrimPrefix(envKey, "_")
+		}
+
+		required := field.Tag.Get("required") == "true"
+		defaultVal := field.Tag.Get("default")
+
+		if field.Type.Kind() == reflect.Struct {
+			err := loadStruct(valueField, envKey)
+			if err != nil {
+				return err
+			}
+			continue
+		}
+
+		envVal := os.Getenv(envKey)
+
+		if envVal == "" {
+			if defaultVal != "" {
+				envVal = defaultVal
+			} else if required {
+				return fmt.Errorf("%w: %s", ErrMissingRequiredEnv, envKey)
+			} else {
+				continue
+			}
+		}
+
+		switch field.Type.Kind() {
+		case reflect.String:
+			valueField.SetString(envVal)
+		case reflect.Int, reflect.Int64:
+			i, err := strconv.ParseInt(envVal, 10, 64)
+			if err != nil {
+				return fmt.Errorf("invalid int for %s: %w", envKey, err)
+			}
+			valueField.SetInt(i)
+		case reflect.Bool:
+			b, err := strconv.ParseBool(envVal)
+			if err != nil {
+				return fmt.Errorf("invalid bool for %s: %w", envKey, err)
+			}
+			valueField.SetBool(b)
+		default:
+			return fmt.Errorf("unsupported type for field %s", field.Name)
+		}
+	}
+
+	return nil
+}