Function wrapHttpFunction

src/function_wrappers.ts:103–128

(execute: HttpFunction)

 * @return An Express handler function
 */
const wrapHttpFunction = (execute: HttpFunction): RequestHandler => {
  return (req: Request, res: Response) => {
    const d = domain.create();
    const errorHandler = (err: Error) => {
      if (res.locals.functionExecutionFinished) {
        console.error(`Exception from a finished function: ${err}`);
      } else {
        res.locals.functionExecutionFinished = true;
        sendCrashResponse({err, res});
      }
    };

    // Catch unhandled errors originating from this request.
    d.on('error', errorHandler);

    d.run(() => {
      process.nextTick(() => {
        const ret = execute(req, res);
        // Catch rejected promises if the function is async.
        if (ret instanceof Promise) {
          ret.catch(errorHandler);
        }
      });
    });
  };
};

/**
 * Wraps an async CloudEvent function in an express RequestHandler.