index.js

const path = require('path');
const fs = require('fs');
const { exec } = require('child_process');
const aws = require('aws-sdk');



module.exports = function({ bucketName, accessKey, accessSecret }) {
    
  const s3Bucket = new aws.S3({
    accessKeyId: accessKey,
    secretAccessKey: accessSecret,
    Bucket: bucketName,
  });

  function dumpDatabase({ uri, backupName, gzip }, callback = (err, backupPath) => {}) {
    const dumpPath = path.resolve(__dirname, backupName)
    const command = `mongodump --uri="${uri} ${gzip ? ' --gzip' : ''}" --archive="${dumpPath}"`;
    exec(command, (err, stdout, stderr) => {
      // We cannot trust stderr cause mongo spits warnings/logs on this channel
      // so we check if the dump was created
      if (err) {
        return callback(err);
      }
      if (!fs.existsSync(dumpPath)) {
        return callback(new Error('Something went wrong'));
      }
      return callback(null, dumpPath);
    })
  
  }
  
  function uploadToS3(file, fileName, callback = (err, data) => {}) {
    s3Bucket.upload({
      Bucket: bucketName,
      Key: fileName,
      Body: file
    }, (err, data) => {
      if (err) {
        return callback(err);
      }
      return callback(null, data);
    })
  }

  return {
    backupDatabase({ uri, backupName, gzip }, callback = () => {}) {
      return new Promise((resolve, reject) => {
        if (!uri || !backupName) {
          throw new Error('uri and backupName are required parameters');
        }
        dumpDatabase({uri, backupName, gzip}, (err, backupPath) => {
          if (err) {
            callback(err);
            return reject(err);
          }
          uploadToS3(fs.createReadStream(backupPath), backupName, (err, data) => {
            if (err) {
              callback(err);
              return reject(err);
            }
            fs.unlink(backupPath, () => {});
            callback(null, data);
            return resolve(data);
          })
        })
      })

    }
  }
}