feat: unify generated configuration loading and extensible decoders

config/config.go

@@ -62,19 +62,19 @@ func Default() Config {
 // Validate checks configuration values before an application starts.
 func (c Config) Validate() error {
 	if err := c.Lifecycle.Validate(); err != nil {
-		return err
+		return AtField("lifecycle", err)
 	}
 	if err := c.Request.Validate(); err != nil {
-		return err
+		return AtField("request", err)
 	}
 	if err := c.Log.Validate(); err != nil {
-		return err
+		return AtField("log", err)
 	}
 	if err := c.Endpoints.Validate(); err != nil {
 		return err
 	}
 	if err := c.Errors.Validate(); err != nil {
-		return err
+		return AtField("errors", err)
 	}
 	encoder := c.ResponseEncoder
 	if encoder == nil {
@@ -90,7 +90,7 @@ func (c Config) Validate() error {
 		return err
 	}
 	if err := c.Response.Validate(); err != nil {
-		return err
+		return AtField("response", err)
 	}
 	if c.SlowRequestThreshold < 0 {
 		return &ConfigError{Field: "slowRequestThreshold", Message: "must be nonnegative"}
@@ -99,13 +99,13 @@ func (c Config) Validate() error {
 		return &ConfigError{Field: "address", Message: "is required"}
 	}
 	if strings.TrimSpace(c.RequestIDHeader) == "" {
-		return &ConfigError{Field: "request_id_header", Message: "is required"}
+		return &ConfigError{Field: "requestIdHeader", Message: "is required"}
 	}
 	if c.ShutdownTimeout <= 0 {
-		return &ConfigError{Field: "shutdown_timeout", Message: "must be positive"}
+		return &ConfigError{Field: "shutdownTimeout", Message: "must be positive"}
 	}
 	if _, err := httpx.NewClientIPResolver(c.TrustedProxies...); err != nil {
-		return &ConfigError{Field: "trusted_proxies", Message: err.Error()}
+		return &Error{Field: "trustedProxies", Reason: "expected IP addresses or CIDRs", cause: err}
 	}
 	return c.ValidateTransport()
 }