Function writeError

internal/barista/observability/telemetry.twirp.go:596–633

writeError writes Twirp errors in the response and triggers hooks.

(ctx context.Context, resp http.ResponseWriter, err error, hooks *twirp.ServerHooks)

// writeError writes Twirp errors in the response and triggers hooks.
func writeError(ctx context.Context, resp http.ResponseWriter, err error, hooks *twirp.ServerHooks) {
	// Convert to a twirp.Error. Non-twirp errors are converted to internal errors.
	var twerr twirp.Error
	if !errors.As(err, &twerr) {
		twerr = twirp.InternalErrorWith(err)
	}

	statusCode := twirp.ServerHTTPStatusFromErrorCode(twerr.Code())
	ctx = ctxsetters.WithStatusCode(ctx, statusCode)
	ctx = callError(ctx, hooks, twerr)

	respBody := marshalErrorToJSON(twerr)

	resp.Header().Set("Content-Type", "application/json") // Error responses are always JSON
	resp.Header().Set("Content-Length", strconv.Itoa(len(respBody)))
	resp.WriteHeader(statusCode) // set HTTP status code and send response

	_, writeErr := resp.Write(respBody)
	if writeErr != nil {
		// We have three options here. We could log the error, call the Error
		// hook, or just silently ignore the error.
		//
		// Logging is unacceptable because we don't have a user-controlled
		// logger; writing out to stderr without permission is too rude.
		//
		// Calling the Error hook would confuse users: it would mean the Error
		// hook got called twice for one request, which is likely to lead to
		// duplicated log messages and metrics, no matter how well we document
		// the behavior.
		//
		// Silently ignoring the error is our least-bad option. It's highly
		// likely that the connection is broken and the original 'err' says
		// so anyway.
		_ = writeErr
	}

	callResponseSent(ctx, hooks)
}

// sanitizeBaseURL parses the the baseURL, and adds the "http" scheme if needed.
// If the URL is unparsable, the baseURL is returned unchanged.