S3/CloudFront plugin for Certbot client

Use the certbot client to generate and install a certificate to be used with an AWS CloudFront distribution of an S3 bucket.

Quick install using Docker on Windows for apex and www domains:

• Run docker build . -t certbot-s3front
• Copy env.example.ps1 to env.ps1 and fill in the details
• Run ./env
• Run ./install

Before you start

Follow a guide like this one https://docs.aws.amazon.com/gettingstarted/latest/swh/website-hosting-intro.html to use S3 and CloudFront for static site hosting.

Once you are done you should have:

• A domain pointing to a CloudFront distribution that will use an S3 bucket for origin.
• Both HTTP and HTTPS traffic are enabled in the CloudFront Distrubtion. This is important for certificate validation, at least while you get your certificate.
• An IAM policy with the permissions needed for this plugin. A sample policy has been provided.

Note: If you're setting up both an apex and a www. domain, they'll have a respective S3 bucket each. You'll need to update the IAM policy to include access to both buckets.

Setup

The easiest way to install both the certbot client and the certbot-s3front plugin is:

pip install certbot-s3front

Mac with Homebrew certbot?

Installed certbot using Homebrew on Mac (as the official way to install on a Mac)? Install the plugin with:

$(brew --prefix certbot)/libexec/bin/pip install certbot-s3front

Note: You will need to re-install the plugin each time certbot is updated through Homebrew.

Mac with pip certbot?

Alternatively, you can have a local set up for Python and we recommend a virtual environment and have both certbot and certbot-s3front installed via pip. You might also need to install dialog: brew install dialog.

Ubuntu?

If you are in Ubuntu you will need to install pip and other libraries first:

apt-get install python-pip python-dev libffi-dev libssl-dev libxml2-dev libxslt1-dev libjpeg8-dev zlib1g-dev dialog

And then run pip install certbot-s3front.

How to use it

To generate a certificate and install it in a CloudFront distribution:

AWS_ACCESS_KEY_ID="REPLACE_WITH_YOUR_KEY" \
AWS_SECRET_ACCESS_KEY="REPLACE_WITH_YOUR_SECRET" \
certbot --agree-tos -a certbot-s3front:auth \
--certbot-s3front:auth-s3-bucket REPLACE_WITH_YOUR_BUCKET_NAME \
[ --certbot-s3front:auth-s3-region your-bucket-region-name ] #(the default is us-east-1, unless you want to set it to something else, you can delete this line) \
[ --certbot-s3front:auth-s3-directory your-bucket-directory ] # (default is "") \
-i certbot-s3front:installer \
--certbot-s3front:installer-cf-distribution-id REPLACE_WITH_YOUR_CF_DISTRIBUTION_ID \
-d REPLACE_WITH_YOUR_DOMAIN

Follow the screen prompts and you should end up with the certificate in your distribution. It may take a couple minutes to update.

Automate renewal

To automate the renewal process without prompts (for example, with a monthly cron), you can add the certbot parameters --renew-by-default --text

Using with Docker

To build a docker image of certbot with the s3front plugin, clone this repo and run:

docker build . -t certbot-s3front

Then export the environment variables to an env.list file:

echo AWS_ACCESS_KEY_ID=YOUR_ID >> env.list
echo AWS_SECRET_ACCESS_KEY=YOUR_KEY >> env.list
echo AWS_S3_BUCKET=YOUR_S3_BUCKET_NAME >> env.list
echo AWS_DISTRIBUTION_ID=YOUR_DISTRIBUTION_ID >> env.list
echo DOMAIN=YOUR_DOMAIN >> env.list
echo EMAIL=YOUR_EMAIL >> env.list

And finally run the docker image:

docker run --rm --name lets-encrypt -it \
    -v ./letsencrypt/:/etc/letsencrypt \
    --env-file env.list \
    certbot-s3front \