Method CreateStep

coderd/x/chatd/chatdebug/service.go:362–432

CreateStep inserts a new debug step and emits a step update event. It returns errRunFinalized if the parent run has already finished, or errRunNotFound if the run_id/chat_id pair does not match an existing run. The finalization guard is enforced atomically by the INSERT's CTE, which issues an UPDATE

(
	ctx context.Context,
	params CreateStepParams,
)

// row lock). This prevents concurrent FinalizeStale from setting
// finished_at between the check and the INSERT.
func (s *Service) CreateStep(
	ctx context.Context,
	params CreateStepParams,
) (database.ChatDebugStep, error) {
	now := s.clock.Now()
	insert := database.InsertChatDebugStepParams{
		RunID:               params.RunID,
		StepNumber:          params.StepNumber,
		Operation:           string(params.Operation),
		Status:              string(params.Status),
		HistoryTipMessageID: nullInt64(params.HistoryTipMessageID),
		AssistantMessageID:  sql.NullInt64{},
		NormalizedRequest:   s.nullJSON(ctx, params.NormalizedRequest),
		NormalizedResponse:  pqtype.NullRawMessage{},
		Usage:               pqtype.NullRawMessage{},
		Attempts:            pqtype.NullRawMessage{},
		Error:               pqtype.NullRawMessage{},
		Metadata:            pqtype.NullRawMessage{},
		StartedAt:           sql.NullTime{Time: now, Valid: true},
		UpdatedAt:           sql.NullTime{Time: now, Valid: true},
		FinishedAt:          sql.NullTime{},
		ChatID:              params.ChatID,
	}

	// Cap retry attempts to prevent infinite loops under
	// pathological concurrency. Each iteration performs two DB
	// round-trips (insert + list), so 10 retries is generous.
	const maxCreateStepRetries = 10

	for range maxCreateStepRetries {
		if err := ctx.Err(); err != nil {
			return database.ChatDebugStep{}, err
		}

		step, err := s.db.InsertChatDebugStep(chatdContext(ctx), insert)
		if err == nil {
			// The INSERT CTE atomically bumps the parent run's
			// updated_at, so no separate touch call is needed.
			s.publishEvent(ctx, step.ChatID, EventKindStepUpdate, step.RunID, step.ID)
			return step, nil
		}
		// The INSERT's locked_run CTE filters on id, chat_id, and
		// finished_at IS NULL, so sql.ErrNoRows can mean "run not
		// found", "chat_id mismatch", or "already finalized." Look
		// the run up to disambiguate instead of conflating
		// caller-side data bugs with the legitimate terminal case.
		if errors.Is(err, sql.ErrNoRows) {
			return database.ChatDebugStep{}, s.classifyMissingRun(ctx, params)
		}
		if !database.IsUniqueViolation(err, database.UniqueIndexChatDebugStepsRunStep) {
			return database.ChatDebugStep{}, err
		}

		steps, listErr := s.db.GetChatDebugStepsByRunID(chatdContext(ctx), params.RunID)
		if listErr != nil {
			return database.ChatDebugStep{}, listErr
		}
		nextStepNumber := insert.StepNumber + 1