feat: add command domain invariants

internal/domain/errors.go

@@ -0,0 +1,83 @@
+package domain
+
+import (
+	"fmt"
+	"unicode/utf8"
+
+	rvboxv1 "github.com/rvbox/rvbox/gen/go/rvbox/v1"
+)
+
+const MaxProtocolDetailBytes = 4 * 1024
+
+// Error is the transport-neutral form of an RVBox structured failure.
+type Error struct {
+	Code      rvboxv1.ControlError_Code
+	Message   string
+	Retryable bool
+	IssueUUID string
+	Cause     error
+}
+
+func (e *Error) Error() string {
+	if e.IssueUUID == "" {
+		return fmt.Sprintf("%s: %s", e.Code, e.Message)
+	}
+	return fmt.Sprintf("%s (%s): %s", e.Code, e.IssueUUID, e.Message)
+}
+
+func (e *Error) Unwrap() error { return e.Cause }
+
+// NewError applies the stable retryability policy and bounds wire-visible text.
+func NewError(code rvboxv1.ControlError_Code, message, issueUUID string) *Error {
+	return &Error{
+		Code:      code,
+		Message:   boundUTF8(message, MaxProtocolDetailBytes),
+		Retryable: DefaultRetryable(code),
+		IssueUUID: issueUUID,
+	}
+}
+
+func (e *Error) WithCause(cause error) *Error {
+	e.Cause = cause
+	return e
+}
+
+func (e *Error) ControlError() *rvboxv1.ControlError {
+	return &rvboxv1.ControlError{
+		Code:      e.Code,
+		Message:   boundUTF8(e.Message, MaxProtocolDetailBytes),
+		Retryable: e.Retryable,
+		IssueUuid: e.IssueUUID,
+	}
+}
+
+func DefaultRetryable(code rvboxv1.ControlError_Code) bool {
+	switch code {
+	case rvboxv1.ControlError_OFFLINE,
+		rvboxv1.ControlError_CAPACITY_EXHAUSTED,
+		rvboxv1.ControlError_TRANSIENT,
+		rvboxv1.ControlError_INTERNAL:
+		return true
+	default:
+		return false
+	}
+}
+
+func NewExecutionContextUnavailable(message, issueUUID string) *Error {
+	return NewError(rvboxv1.ControlError_CODE_EXECUTION_CONTEXT_UNAVAILABLE, message, issueUUID)
+}
+
+func NewElevationUnavailable(message, issueUUID string) *Error {
+	return NewError(rvboxv1.ControlError_CODE_ELEVATION_UNAVAILABLE, message, issueUUID)
+}
+
+func boundUTF8(value string, limit int) string {
+	if len(value) <= limit {
+		return value
+	}
+	value = value[:limit]
+	for !utf8.ValidString(value) {
+		value = value[:len(value)-1]
+	}
+	return value
+}