fix: make environment variables case insensitive where necessary (#954)

fix #935

backend/internal/common/env_config.go

@@ -32,17 +32,17 @@ const (
 )
 
 type EnvConfigSchema struct {
-	AppEnv             string     `env:"APP_ENV"`
-	LogLevel           string     `env:"LOG_LEVEL"`
-	AppURL             string     `env:"APP_URL"`
-	DbProvider         DbProvider `env:"DB_PROVIDER"`
+	AppEnv             string     `env:"APP_ENV" options:"toLower"`
+	LogLevel           string     `env:"LOG_LEVEL" options:"toLower"`
+	AppURL             string     `env:"APP_URL" options:"toLower"`
+	DbProvider         DbProvider `env:"DB_PROVIDER" options:"toLower"`
 	DbConnectionString string     `env:"DB_CONNECTION_STRING" options:"file"`
 	UploadPath         string     `env:"UPLOAD_PATH"`
 	KeysPath           string     `env:"KEYS_PATH"`
 	KeysStorage        string     `env:"KEYS_STORAGE"`
 	EncryptionKey      []byte     `env:"ENCRYPTION_KEY" options:"file"`
 	Port               string     `env:"PORT"`
-	Host               string     `env:"HOST"`
+	Host               string     `env:"HOST" options:"toLower"`
 	UnixSocket         string     `env:"UNIX_SOCKET"`
 	UnixSocketMode     string     `env:"UNIX_SOCKET_MODE"`
 	MaxMindLicenseKey  string     `env:"MAXMIND_LICENSE_KEY" options:"file"`
@@ -112,31 +112,40 @@ func parseEnvConfig() error {
 		return fmt.Errorf("error parsing env config: %w", err)
 	}
 
-	err = resolveFileBasedEnvVariables(&EnvConfig)
+	err = prepareEnvConfig(&EnvConfig)
+	if err != nil {
+		return fmt.Errorf("error preparing env config: %w", err)
+	}
+
+	err = validateEnvConfig(&EnvConfig)
 	if err != nil {
 		return err
 	}
 
-	// Validate the environment variables
-	EnvConfig.LogLevel = strings.ToLower(EnvConfig.LogLevel)
-	if _, err := sloggin.ParseLevel(EnvConfig.LogLevel); err != nil {
+	return nil
+
+}
+
+// validateEnvConfig checks the EnvConfig for required fields and valid values
+func validateEnvConfig(config *EnvConfigSchema) error {
+	if _, err := sloggin.ParseLevel(config.LogLevel); err != nil {
 		return errors.New("invalid LOG_LEVEL value. Must be 'debug', 'info', 'warn' or 'error'")
 	}
 
-	switch EnvConfig.DbProvider {
+	switch config.DbProvider {
 	case DbProviderSqlite:
-		if EnvConfig.DbConnectionString == "" {
-			EnvConfig.DbConnectionString = defaultSqliteConnString
+		if config.DbConnectionString == "" {
+			config.DbConnectionString = defaultSqliteConnString
 		}
 	case DbProviderPostgres:
-		if EnvConfig.DbConnectionString == "" {
+		if config.DbConnectionString == "" {
 			return errors.New("missing required env var 'DB_CONNECTION_STRING' for Postgres database")
 		}
 	default:
 		return errors.New("invalid DB_PROVIDER value. Must be 'sqlite' or 'postgres'")
 	}
 
-	parsedAppUrl, err := url.Parse(EnvConfig.AppURL)
+	parsedAppUrl, err := url.Parse(config.AppURL)
 	if err != nil {
 		return errors.New("APP_URL is not a valid URL")
 	}
@@ -145,10 +154,10 @@ func parseEnvConfig() error {
 	}
 
 	// Derive INTERNAL_APP_URL from APP_URL if not set; validate only when provided
-	if EnvConfig.InternalAppURL == "" {
-		EnvConfig.InternalAppURL = EnvConfig.AppURL
+	if config.InternalAppURL == "" {
+		config.InternalAppURL = config.AppURL
 	} else {
-		parsedInternalAppUrl, err := url.Parse(EnvConfig.InternalAppURL)
+		parsedInternalAppUrl, err := url.Parse(config.InternalAppURL)
 		if err != nil {
 			return errors.New("INTERNAL_APP_URL is not a valid URL")
 		}
@@ -157,25 +166,26 @@ func parseEnvConfig() error {
 		}
 	}
 
-	switch EnvConfig.KeysStorage {
+	switch config.KeysStorage {
 	// KeysStorage defaults to "file" if empty
 	case "":
-		EnvConfig.KeysStorage = "file"
+		config.KeysStorage = "file"
 	case "database":
-		if EnvConfig.EncryptionKey == nil {
+		if config.EncryptionKey == nil {
 			return errors.New("ENCRYPTION_KEY must be non-empty when KEYS_STORAGE is database")
 		}
 	case "file":
 		// All good, these are valid values
 	default:
-		return fmt.Errorf("invalid value for KEYS_STORAGE: %s", EnvConfig.KeysStorage)
+		return fmt.Errorf("invalid value for KEYS_STORAGE: %s", config.KeysStorage)
 	}
 
 	return nil
+
 }
 
-// resolveFileBasedEnvVariables uses reflection to automatically resolve file-based secrets
-func resolveFileBasedEnvVariables(config *EnvConfigSchema) error {
+// prepareEnvConfig processes special options for EnvConfig fields
+func prepareEnvConfig(config *EnvConfigSchema) error {
 	val := reflect.ValueOf(config).Elem()
 	typ := val.Type()
 
@@ -183,48 +193,65 @@ func resolveFileBasedEnvVariables(config *EnvConfigSchema) error {
 		field := val.Field(i)
 		fieldType := typ.Field(i)
 
-		// Only process string and []byte fields
-		isString := field.Kind() == reflect.String
-		isByteSlice := field.Kind() == reflect.Slice && field.Type().Elem().Kind() == reflect.Uint8
-		if !isString && !isByteSlice {
-			continue
-		}
-
-		// Only process fields with the "options" tag set to "file"
 		optionsTag := fieldType.Tag.Get("options")
-		if optionsTag != "file" {
-			continue
-		}
+		options := strings.Split(optionsTag, ",")
 
-		// Only process fields with the "env" tag
-		envTag := fieldType.Tag.Get("env")
-		if envTag == "" {
-			continue
-		}
-
-		envVarName := envTag
-		if commaIndex := len(envTag); commaIndex > 0 {
-			envVarName = envTag[:commaIndex]
-		}
-
-		// If the file environment variable is not set, skip
-		envVarFileName := envVarName + "_FILE"
-		envVarFileValue := os.Getenv(envVarFileName)
-		if envVarFileValue == "" {
-			continue
-		}
-
-		fileContent, err := os.ReadFile(envVarFileValue)
-		if err != nil {
-			return fmt.Errorf("failed to read file for env var %s: %w", envVarFileName, err)
-		}
-
-		if isString {
-			field.SetString(strings.TrimSpace(string(fileContent)))
-		} else {
-			field.SetBytes(fileContent)
+		for _, option := range options {
+			switch option {
+			case "toLower":
+				if field.Kind() == reflect.String {
+					field.SetString(strings.ToLower(field.String()))
+				}
+			case "file":
+				err := resolveFileBasedEnvVariable(field, fieldType)
+				if err != nil {
+					return err
+				}
+			}
 		}
 	}
 
 	return nil
 }
+
+// resolveFileBasedEnvVariable checks if an environment variable with the suffix "_FILE" is set,
+// reads the content of the file specified by that variable, and sets the corresponding field's value.
+func resolveFileBasedEnvVariable(field reflect.Value, fieldType reflect.StructField) error {
+	// Only process string and []byte fields
+	isString := field.Kind() == reflect.String
+	isByteSlice := field.Kind() == reflect.Slice && field.Type().Elem().Kind() == reflect.Uint8
+	if !isString && !isByteSlice {
+		return nil
+	}
+
+	// Only process fields with the "env" tag
+	envTag := fieldType.Tag.Get("env")
+	if envTag == "" {
+		return nil
+	}
+
+	envVarName := envTag
+	if commaIndex := len(envTag); commaIndex > 0 {
+		envVarName = envTag[:commaIndex]
+	}
+
+	// If the file environment variable is not set, skip
+	envVarFileName := envVarName + "_FILE"
+	envVarFileValue := os.Getenv(envVarFileName)
+	if envVarFileValue == "" {
+		return nil
+	}
+
+	fileContent, err := os.ReadFile(envVarFileValue)
+	if err != nil {
+		return fmt.Errorf("failed to read file for env var %s: %w", envVarFileName, err)
+	}
+
+	if isString {
+		field.SetString(strings.TrimSpace(string(fileContent)))
+	} else {
+		field.SetBytes(fileContent)
+	}
+
+	return nil
+}