Use callbacks to fetch from AWS S3, on a machine with pre-configured access

sample.js

        var AWS = require('aws-sdk');
        var s3 = new AWS.S3();
        s3.getObject({
            Bucket: 'bucket-name',
            Key: 'file-name.ext'
        }, function (err, data) {
            if (err) {
                logger.error(err);
                returnResponse(res, 500, logger, 'Internal Server Error') ;
            }
            else {
                var parsedData;
                try {
                    parsedData = JSON.parse(data.Body.toString());
                    logger.debug('parsedData:', parsedData);
                    returnResponse(res, 200, logger, 'done') ;
                } catch (e) {
                    logger.error(e);
                    returnResponse(res, 500, logger, 'Internal Server Error') ;
                }
            }
        });

function returnResponse(httpResponse, status, logger, message) {
    if (status === 200) {
        logger.info(message);
    } else {
        logger.error(message);
    }

    httpResponse.writeHead(status);
    httpResponse.write(message);
    httpResponse.end();
}