> Be assumption that almost restrictions are resolved from AWS support, your AWS Lambda function was ready to get tips and implementation.

• Author from scratch (start with a simple Hello World example.)
• Function Name: flagtickDemoFunc
• Runtime: Node.js 14.x
• Architecture: x86_64
• Create a new role with basic Lambda permissions
• Advanced settings (uncheck all checkboxes)

> Add Layers to Lambda function

> To create custom layer for Node.js in Lambda function, you need to determine which dependencies was built and use in Lambda function.

const { Pool, Client } = require('pg')

Note: As we observe ('pg') was used in code implementation, we need to create folder as structure below.

+ nodejs
+ nodejs/node_modules
+ nodejs/package.json
+ nodejs/package-lock.json

Here is details of package.json

{
  "name": "pg",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "pg": "^8.7.1"
  }
}

Running command npm install to generate automatically package-lock.json and node_modules. If we are still lack of dependencies, then you can totally update in package.json and run the command again. After that, let move and update in Layers of Lambda dashboard.

Note: Use generated folder and wrap as zip format to upload.

> Try to make an connection to Amazon RDS

exports.handler = async (event, context) => {
    
    var dbConfig = {
        user: "flagtickpostgres",
        password: "qOi828&^oNLI",
        database: "powerbi",
        host: "powerbi.bbioeyff8icc.us-west-2.rds.amazonaws.com",
        port: '5432'
    };
    const pool = new pg.Pool(dbConfig);
    let client = await pool.connect();
    
    let queryExample = "SELECT * FROM \"users\"";

    let res = await new Promise((resolve) => {
       client.query(queryExample, (err, res) => {
          if (err !== null) {
              resolve(err);
          } else {
              resolve(res);
          }
          client.end();
        }); 
    });
    
    const response = {
        statusCode: 200,
        body: JSON.stringify(res),
    };
    return response;
};

> You can refer link here to get more instructions about pg.