add S3 Bucket Cache Control to existing Objects, with pagination

addCacheControl.js

/* global require */

// this script iterates through all maps in the bucket
// and adds the "CacheControl" header
// if any keys fail, it will write them out to a file at the end of the crawl

const fs = require('fs');
const _ = require('lodash');
const AWS = require('aws-sdk');
const Promise = require('bluebird');

const s3 = new AWS.S3();
Promise.promisifyAll(s3);

const Bucket = '<bucket-name>';
const Prefix = '<bucket-prefix>';
const CacheControl = 'max-age=2592000';

let failed = [];

async function process(objs) {
    // map doesnt happen serially, thats good for performance
    return Promise.map(objs, async obj => {
        let Key = obj.Key;

        try {
            let headData = await s3.headObjectAsync({ Bucket, Key });

            if (headData.ContentType !== 'image/png') {
                console.log(`skip-not-image: ${Key}`);
                return;
            }

            if (_.has(headData, 'CacheControl')) {
                console.log(`skip-processed: ${Key}`);
                return;
            }

            try {
                let result = await s3.copyObjectAsync({
                    Bucket,
                    Key,
                    CopySource: `/${Bucket}/${Key}`,
                    CacheControl,
                    MetadataDirective: 'REPLACE',
                    ContentType: headData.ContentType
                });
                console.log(`completed:      ${Key}`);
            } catch (err) {
                console.error(`copyObject Error ${Key}`);
                console.log(err);
                failed.push(Key);
            }
        } catch (err) {
            console.error(`headObject Error ${Key}`);
            console.log(err);
            failed.push(Key);
        }
    });
}

async function run(ContinuationToken = undefined) {
    try {
        let config = _.omitBy({ Bucket, Prefix, ContinuationToken }, _.isNil);
        let objs = await s3.listObjectsV2Async(config);

        console.log('paginate: ', objs.IsTruncated);

        // heres the recursive pagination call
        let next = objs.IsTruncated ? run(objs.NextContinuationToken) : Promise.resolve();

        await Promise.all([next, process(objs.Contents)]);
    } catch (err) {
        console.error('listObjects Error');
        console.log(err);
    }
}

run().then(r => {
    console.log(`${failed.length}: failed`);
    if (failed.length > 0) {
        console.log('wrote list of failed keys to "failed.json"');
        fs.writeFileSync('failed.json', JSON.stringify(failed));
    }
});