CopySnapshotToDR.js

/*
    // Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
    // SPDX-License-Identifier: MIT-0.
*/
// Sample Lambda function to copy an EBS snapshot to a different region
var AWS = require('aws-sdk');
var ec2 = new AWS.EC2();

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

    //pull the destination region from the environment variables
    var destinationRegion = process.env.destRegion;

    //pull the source region from the source volume-id ->  "arn:aws:ec2::region:volume/volume-id"
    var sourceRegion = event.detail.source.substring(event.detail.source.indexOf('::') + 2);
    sourceRegion = sourceRegion.substring(0,sourceRegion.indexOf(":"));
    console.log("source region: " + sourceRegion);

    // Get the EBS snapshot ID and volume ID from the CloudWatch event details
    var snapshotId = event.detail.snapshot_id.substring(
      event.detail.snapshot_id.indexOf('/') + 1);
    var volumeId = event.detail.source.substring(
      event.detail.source.indexOf('/') + 1)

    //Add information regarding the original volume to the description
    //  so have access to it in DR region
    const description = `${snapshotId}**${volumeId}**${sourceRegion}`;
    console.log ("snapshotId:", snapshotId);

    // Load EC2 class and update the configuration to use destination region
    //  to initiate the snapshot.
    // **Note copySnapshot commands are performed against the destination region
    AWS.config.update({region: destinationRegion});
    var ec2 = new AWS.EC2();

    // Prepare variables for ec2.modifySnapshotAttribute call
    const copySnapshotParams = {
        Description: description,
        DestinationRegion: destinationRegion,
        SourceRegion: sourceRegion,
        SourceSnapshotId: snapshotId
    };

    // Execute the copy snapshot and log any errors
    ec2.copySnapshot(copySnapshotParams, (err, data) => {
        if (err) {
            const errorMessage = `Error copying snapshot ${snapshotId} to region ${destinationRegion}.`;
            console.log(errorMessage);
            console.log(err);
            callback(errorMessage);
        } else {
            const successMessage = `Successfully started copy of snapshot ${snapshotId} to region ${destinationRegion}.`;
            console.log(successMessage);
            console.log(data);
            callback(null, successMessage);
        }
    });
};