s3cf

s3cf

A go program that syncs a static website to an S3 bucket and purges URLs stored in Cloudflare's edge cache.

This program uses the AWS CLI to execute the sync command using the --size-only and --delete options. The --delete option makes sure files that have been deleted locally are removed from the bucket and the --size-only option prevents local files from being copied to the S3 bucket if they have been regenerated before syncing (for example, using hugo build).

Since it's possible for locally modified files to be missed by the --size-only option, the program will also do a second pass comparing the MD5 of each local file with the remote ETag value. If they don't match, the local file will overwrite the file stored in the S3 bucket.

Prerequisites

This program requires version 2.0+ of the AWS CLI to be installed alongside s3cf and the AWS environment variables need set with credentials that have permissions to access S3.

Building

Clone the repo then run the following commands:

go mod download
go build

Environment Variables

The minimum required environment variables are the AWS credentials. This will allow you to sync to an S3 bucket but will not purge URLs from the Cloudflare edge cache.

AWS_ACCESS_KEY_ID=<aws_access_key_id>
AWS_SECRET_ACCESS_KEY=<aws_secret_access_key>

The following variables are required in order to purge modified URLS from Cloudflare's edge cache.

S3CF_CF_API_KEY=<cloudflare_api_key>
S3CF_CF_API_EMAIL=<cloudflare_email>
S3CF_CF_API_ZONE=<cloudflare_zone_id>
S3CF_CF_BASE_URL=<https://mywebsite.com>

Usage

The following command will sync the contents of the www folder to the S3 bucket named mybucketname and purge the cache of any modified URLS.

s3cf www s3://mybucketname

Output:

Syncing www with s3://mybucketname
(dryrun) upload: www/hello-world/index.html to s3://mybucketname/hello-world/index.html
(dryrun) upload: www/index.html to s3://mybucketname/index.html
Purging URLs from CloudFlare Cache
Purged: [https://mywebsite.com/hello-world/, https://mywebsite.com/]

Building with Docker

In order to make sure s3cf works on multiple machines, you can use a Docker image. The repo includes a Dockerfile which takes care of installing s3cf and bundling it with the latest AWS CLI. It can be built using the following command:

./version build

To publish to Docker Hub run:

DOCKER_ID=<yourcompany> ./version publish

Running Docker image

The following example shows how to run s3cf from inside the Docker image.

docker run --rm -it \
-e AWS_ACCESS_KEY_ID="$AWS_ACCESS_KEY_ID" \
-e AWS_SECRET_ACCESS_KEY="$AWS_SECRET_ACCESS_KEY" \
-e S3CF_CF_API_KEY="$S3CF_CF_API_KEY" \
-e S3CF_CF_API_EMAIL="$S3CF_CF_API_EMAIL" \
-e S3CF_CF_API_ZONE="$S3CF_CF_API_ZONE" \
-e S3CF_CF_BASE_URL="$S3CF_CF_BASE_URL" \
-v $(pwd):/s3cf <yourcompany>/s3cf www s3://mybucketname

License

MIT License

Copyright (c) 2020 Tony Mackay

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.