Getting Sequelize.js library to work on Amazon Lambda

Thanks to dashmugs comment after some investigation on this page (https://github.com/serverless-heaven/serverless-webpack), there is a section on Forced Inclusion. I'll paraphrase it here.

Forced inclusion Sometimes it might happen that you use dynamic requires in your code, i.e. you require modules that are only known at runtime. Webpack is not able to detect such externals and the compiled package will miss the needed dependencies. In such cases you can force the plugin to include certain modules by setting them in the forceInclude array property. However the module must appear in your service's production dependencies in package.json.

# serverless.yml
custom:
  webpackIncludeModules:
    forceInclude:
      - module1
      - module2

So I simply did this...

webpackIncludeModules:
    forceInclude:
      - mysql
      - mysql2

Now it works! Hope this helps someone else with the same issue.

None of the previous helped me, I used this solution: https://github.com/sequelize/sequelize/issues/9489#issuecomment-493304014

The trick is to use dialectModule property and override sequelize.

import Sequelize from 'sequelize';
import mysql2 from 'mysql2'; // Needed to fix sequelize issues with WebPack

const sequelize = new Sequelize(
  process.env.DB_NAME,
  process.env.DB_USER,
  process.env.DB_PASSWORD,
  {
    dialect: 'mysql',
    dialectModule: mysql2, // Needed to fix sequelize issues with WebPack
    host: process.env.DB_HOST,
    port: process.env.DB_PORT
  }
)

export async function connectToDatabase() {
  console.log('Trying to connect via sequelize')
  await sequelize.sync()
  await sequelize.authenticate()
  console.log('=> Created a new connection.')

  // Do something 
}

The previous so far works on MySql but is not working with Postgres