flex-template-web/server/log.js

/**
 * Error logging for the Flex template server. Can be used to
 * strap on an external error logging service like Sentry
 * or just plain printing errors to the log.
 */

const Sentry = require('@sentry/node');

const ENV = process.env.REACT_APP_ENV;
const SENTRY_DSN = process.env.REACT_APP_SENTRY_DSN;

/**
 * Set up error loggin. If a Sentry DSN is defined
 * Sentry client is configured.
 */
exports.setup = () => {
  if (SENTRY_DSN) {
    // Configure the Sentry client. As is, this catches unhandled
    // exceptions from starting the server etc. but does not catch the
    // ones thrown from Express.js middleware functions. For those
    // an error handler has to be added to the Express app.
    Sentry.init({ dsn: SENTRY_DSN, environment: ENV });
  }
};

/**
 * Returns a Sentry request handler in case
 * Sentry client is set up.
 */
exports.requestHandler = () => {
  if (SENTRY_DSN) {
    return Sentry.Handlers.requestHandler();
  } else {
    return (req, res, next) => {
      next();
    };
  }
};

/**
 * Returns a Sentry error handler in case
 * Sentry client is set up.
 */
exports.errorHandler = () => {
  if (SENTRY_DSN) {
    return Sentry.Handlers.errorHandler();
  } else {
    return (err, req, res, next) => {
      next(err);
    };
  }
};

const responseAPIErrors = error => {
  return error && error.data && error.data.errors ? error.data.errors : [];
};

const responseApiErrorInfo = err =>
  responseAPIErrors(err).map(e => ({
    status: e.status,
    code: e.code,
    meta: e.meta,
  }));

/**
 * Logs a error. If Sentry client is set up
 * passes the error to that. Otherwise prints
 * the error to `console.error`.
 *
 * @param {Error} e Error that occurred
 * @param {String} code Error code
 * @param {Object} data Additional data to be sent to Sentry
 */
exports.error = (e, code, data) => {
  if (SENTRY_DSN) {
    const extra = { ...data, apiErrorData: responseApiErrorInfo(e) };

    Sentry.withScope(scope => {
      scope.setTag('code', code);
      Object.keys(extra).forEach(key => {
        scope.setExtra(key, extra[key]);
      });
      Sentry.captureException(e);
    });
  } else {
    console.error(e);
    console.error(code);
    console.error(data);
  }
};