AWS lambda Error: Please install pg package manually

Question

I'm trying to bundle lambda code with webpack and my code uses sequelize and postgres. This has been a very frustrating process because I've done what other questions have suggested. I've tried excluding pg-native and I've tried force including pg but I still get the same error. My webpack config looks like

const path = require("path")
const glob = require("glob")
const pg = require('pg');


module.exports = {
    target: 'node',
    entry: './app.js', 
    module: {
        rules: [
            {
                test: /\.js$/,
                use: [{
                    loader: 'babel-loader',
                    options: {
                        include: [pg] + glob.sync("../../database/migrations/*.js")
                    },
                }]
            },
        ]
    },
    devtool: 'source-map',
    output: {
        path: path.resolve(__dirname, "dist"),
        filename: '[name].js',
        libraryTarget: 'commonjs2',
    }
}

My app.js looks like

const sdk = require('aws-sdk');
const Sequelize = require('sequelize');
const pg = require('pg');
const { Umzug, SequelizeStorage } = require('umzug');


exports.handler = async function (event, context, callback) {

let secretArn = process.env.DATABASE_SECRET_ARN;
let db_user = process.env.DATABASE_USER;
let db_endpoint = process.env.DATABASE_ENDPOINT;
let db_port = process.env.DATABASE_PORT;
let db_name = process.env.DATABASE_NAME;
console.log('here',JSON.stringify(secretArn));
try {
    console.log(secretArn);
    //Setup secret manager connection and get the json of the secret value, and its assocated properties
    let secretResponse = await new sdk.SecretsManager().getSecretValue({ SecretId: secretArn }).promise();
    console.log('got the secret')
    //Decode and parse the values to actually use them
    let secretValue;
    if (secretResponse.SecretString != null || secretResponse.secretResponse != undefined) {
        secretValue = secretResponse.SecretString
    } else {
        var buff = Buffer.from(secretResponse.SecretString, 'base64');
        secretValue = buff.toString('ascii');
    }
    let secretJson = JSON.parse(secretValue);


    //Create Connection
    console.log("Setting up connection")
    //Connection String generation
    const sequelize = new Sequelize.Sequelize(db_name, db_user, secretJson.password,
        { host: db_endpoint, port: db_port, dialect: 'postgres' });
    }
}

The code fails when the const sequelize line is ran. Has anyone else ran into this issue I have got it to work without webpack but I would rather it be bundled.

Answer 1

I made comment above that I was experiencing the same issue. After further investigation, I found that I could force the Sequelize library to avoid a lookup of pg-native by passing a dialectModule parameter in addition to a dialect parameter.

const sequelize = new Sequelize.Sequelize(
    db_name,
    db_user, 
    secretJson.password,
    {
        host: db_endpoint,
        port: db_port,
        dialect: 'postgres'
        dialectModule: require('pg')
    }
);

In my case, I also needed to confirm that the host parameter was set in the right place, but that's not the case in this question.