offline.js

const util = require('util');
const { spawn } = require('child_process');
const moment = require('moment');
const exec = util.promisify(require('child_process').exec);
const AWS = require('aws-sdk');
const sts = new AWS.STS();
const iam = new AWS.IAM();
const { table } = require('./config.json');

const tableNames = {};
Object.keys(table).forEach((k) => (tableNames[k] = k));

const indexNames = {};
Object.keys(table).forEach((k) => {
    if (typeof table[k].GlobalSecondaryIndexes !== 'undefined') {
        const gsi = table[k].GlobalSecondaryIndexes;
        gsi.forEach((i) => {
            indexNames[i.IndexName] = i.IndexName;
        });
    }
});

const stage = process.env.npm_lifecycle_event;

async function getCallerIdentityAccuont() {
    try {
        const callerIdentityPromise = await sts.getCallerIdentity().promise();
        const callerIdentity = callerIdentityPromise.Account;
        return callerIdentity;
    } catch (e) {
        console.error(e);
    }
}

(async function () {
    const accountId = await getCallerIdentityAccuont();
    const roleName = 'YOUR_IAM_ROLE'; // You should put your iam role here if you need to assume role to make request to the cloud databases
    let accessKeyId = process.env.AWS_ACCESS_KEY_ID;
    let secretAccessKey = process.env.AWS_SECRET_ACCESS_KEY;
    let sessionToken;
    if (roleName !== 'YOUR_IAM_ROLE') {
        const getRole = await iam.getRole({ RoleName: roleName }).promise();
        const timestamp = moment(new Date()).format('YYYY-MM-DD');
        const { stdout } = await exec(
            `aws sts assume-role --role-arn ${getRole.Role.Arn} --role-session-name deploy-${timestamp}`,
        );
        const result = JSON.parse(stdout);
        const { AccessKeyId, SecretAccessKey, SessionToken } =
            result.Credentials;
        accessKeyId = AccessKeyId;
        secretAccessKey = SecretAccessKey;
        sessionToken = SessionToken;
    }

    const config = {
        stdio: 'inherit',
        env: {
            stage: stage,
            accountId,
            ...tableNames,
            ...indexNames,
            AWS_ACCESS_KEY_ID: accessKeyId,
            AWS_SECRET_ACCESS_KEY: secretAccessKey,
            ...(typeof sessionToken !== 'undefined' && {
                AWS_SESSION_TOKEN: sessionToken,
            }),
        },
    };
    console.log(config);

    const offline = spawn('serverless', ['offline'], config);
    offline.on('error', (err) => console.error(err));
})();