TagSnapshots.js

/*
    // Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
    // SPDX-License-Identifier: MIT-0.
*/
var AWS = require('aws-sdk');
var ec2 = new AWS.EC2();

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

    console.log(JSON.stringify(event));

    var volumeId = event.detail.source.substring(event.detail.source.indexOf('/') + 1);
    var snapshotId = event.detail.snapshot_id.substring(event.detail.snapshot_id.indexOf('/') + 1);
    var name = volumeId + '_' + event.detail.startTime;

    console.log('volume Id: ' + volumeId);
    console.log('snapshot Id: ' + snapshotId);

    var params = {
        Resources: [
            snapshotId
        ],
        Tags: [{
                Key: "AutomatedSnapName",
                Value: name
            },
            {
                Key: "OriginalVolumeId",
                Value: volumeId
            }
        ]
    };

    determineValidTags(volumeId, callback, function() {
        ec2.createTags(params, function(err, data) {
            if (err) {
                console.log(err, err.stack); // an error occurred
                callback(err);
            } else {
                console.log(data); // successful response
                callback(null, volumeId);
            }
        });
    });
};

function determineValidTags(volumeId, lambdaCallback, callback) {

    /*
      If a tagKey environment variable exists, then that indicates we should
      only perform the backup procedures on snapshots with that tagKey
    */
    var tagToInclude = process.env.tagKey;
    if (tagToInclude != null && tagToInclude != "none") {
        //Pull the description of the volume
        var params = {
            VolumeIds: [volumeId],
            Filters: [{
                Name: "tag-key",
                Values: [
                    tagToInclude
                ]
            }]
        };

        console.log("describeVolumes parameters: " + params);
        ec2.describeVolumes(params, function(err, data) {
            if (err) {
                console.log(err, err.stack); // an error occurred
                lambdaCallback('Error in Finding Original Volume details for: ' + volumeId);
            } else {
                var numVolumes = data.Volumes.length;
                console.log("Number of volumes found = " + numVolumes);

                // This indicates that the tagKey environment variable was specified
                //  AND the current snapshot did NOT originate from a volume that contained
                //  that tag, so we will move on
                if (numVolumes == 0) {
                    console.log("The volume does not contain the specified tag: " + tagToInclude +
                        ".  Exiting the function.");
                    lambdaCallback(null, "VOLUME_NOT_TAGGED");
                }

                callback();
            }
        });
    }
    else {
      callback();
    }
};