certbot-dns-desec: Get Let's Encrypt Certificates for Domains Hosted at deSEC

Certbot plugin to obtain TLS certificates from Let's Encrypt for domains hosted with deSEC.io, using the DNS challenge challenge mechanism.

Installation

To get certificates from Let's Encrypt, install certbot and this plugin. There are many ways to install certbot, this guide uses Python's pip:

python3 -m pip install certbot certbot-dns-desec

Prerequisites

To get a Let's Encrypt certificate for your domain $DOMAIN, you need a deSEC API token $TOKEN with sufficient permission for performing the required DNS changes on your domain. Also make sure that your domain name has been delegated to deSEC (in other words: make sure that the parent registry has the right NS records).

If you don't have a token yet, an easy way to obtain one is by logging into your account at deSEC.io. Navigate to "Token Management" and create a new one. It's good practice to restrict the token permissions as much as possible, e.g. by setting the maximum unused period to four months. This way, the token will expire if it is not continuously used to renew your certificate. Tokens can also be created using the deSEC API.

Request Certificate

To issue and renew certificates using certbot-dns-desec, an access token to your deSEC account is required. To store such a token in a secure location, use, e.g.:

DOMAIN=example.com
TOKEN=your-desec-access-token
sudo mkdir -p /etc/letsencrypt/secrets/
sudo chmod 700 /etc/letsencrypt/secrets/
echo "dns_desec_token = $TOKEN" | sudo tee /etc/letsencrypt/secrets/$DOMAIN.ini
sudo chmod 600 /etc/letsencrypt/secrets/$DOMAIN.ini

Adjust $DOMAIN and $TOKEN according to your domain and deSEC access token, respectively. The file location is just a suggestion and can be changed.

With the credentials stored, you can request a wildcard certificate for your domain by using, e.g.,

certbot certonly \
     --authenticator dns-desec \
     --dns-desec-credentials /etc/letsencrypt/secrets/$DOMAIN.ini \
     -d "$DOMAIN" \
     -d "*.$DOMAIN"

In this command, --authenticator dns-desec activates the certbot-dns-desec plugin; the --dns-desec-credentials argument provides the deSEC access token location to the plugin. These flags can be combined with more sophisticated usages of certbot, e.g. to automatically reload servers after the renewal process. Such functionality is independent of this plugin; for details, see the certbot documentation.

CLI Interface

This plugin is activated by passing the --authenticator dns-desec argument to certbot. It accepts the following command line arguments:

1. --dns-desec-credentials <file> Specifies the file holding the deSEC API credentials (required, see below).
2. --dns-desec-propagation-seconds Waiting time for DNS to propagate before asking the ACME server to verify the DNS record.

Credentials File Format

An example credentials.ini file:

dns_desec_token = token

Additionally, the URL of the deSEC API can be specified using the dns_desec_endpoint configuration option. https://desec.io/api/v1/ is the default.

Development and Testing

To test certbot-dns-desec, create a virtual environment at venv/ for this repository and activate it. Register a domain $DOMAIN with desec.io, and obtain a DNS management token $TOKEN. Then run

python3 -m pip install .
TOKEN=token-you-obtained-from-desec-io
DOMAIN=domain-you-registered-at-desec-io
EMAIL=youremail@example.com
echo "dns_desec_token = $TOKEN" > desec-secret.ini
chmod 600 desec-secret.ini
./venv/bin/certbot \
    --config-dir tmp/certbot/config \
    --logs-dir tmp/certbot/logs \
    --work-dir tmp/certbot/work \
    --test-cert \
    -d $DOMAIN -d "*.$DOMAIN" \
    --authenticator dns-desec \
    --dns-desec-credentials desec-secret.ini \
    --non-interactive --agree-tos \
    --email $EMAIL \
    certonly

Maintenance: Prepare New Release

1. Make sure tests are okay (see GitHub actions)
2. Commit all changes
3. Clean up dist/ folder
4. Set up new release version: RELEASE=x.y.z
5. Update version to x.y.z in setup.py
6. Commit with message "Release Version vx.y.z": git commit -p -m "Release Version v$RELEASE"
7. Tag commit using git tag -as v$RELEASE -m "Release Version v$RELEASE"
8. Push
   1. branch: git push
   2. tag: git push origin v$RELEASE
9. Set environment variables GITHUB_TOKEN to a GitHub token, TWINE_USERNAME and TWINE_PASSWORD to PyPi credentials.
10. Publish using python3 -m publish desec-io certbot-dns-desec