How to start and stop EC2 instance using Lambda?

Question

I need to start and stop EC2 instances using lambda, & for this, I'm using Node.js to write the script. But when executing the script it is not affected. I'm providing the script below:

const AWS = require('aws-sdk');

exports.handler = async (event) => {

const ec2 = new AWS.EC2({ region: event.instanceRegion });

 ec2.stopInstances({ InstanceIds: [event.instanceId] }).promise()

    .then(() => callback(null, `Successfully stopped ${event.instanceId}`))

    .catch(err => callback(err));

};

Please help me to resolve this issue.

Answer 1

You can make use of 'callback' when using the synchronous functions, when using async you should return a promise, like:

const AWS = require('aws-sdk');

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

const ec2 = new AWS.EC2({ region: event.instanceRegion });

 return ec2.stopInstances({ InstanceIds: [event.instanceId] }).promise()

    .then(() => `Successfully stopped ${event.instanceId}`)

    .catch(err => console.log(err));

};

Actually here when you use 'async' you are returning nothing but "null" as a response so it will just terminate and the 'stop instance' will not finish its work.

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