fedeabella/cloudflare-ddns repository overview

⁠Cloudflare Dynamic IP Updater

A simple, to the point python script to update Cloudflare DNS records with a dynamic IP. Also possible using Docker.

I recently set up my first homelab, using Cloudflare⁠ to reverse proxy into it from my own domain. But having an ISP that only provides dynamic IPs, I needed some way to update the IP in the DNS records. There's several solutions for this around, but none that I found were completely to my liking, so I decided to make my own.

⁠Features

• Simple python script which does the bare minimum
• Lean Docker image when built, with no network or exposed ports needed
• Minimal pip requirements
• Uses Cloudflare's own python library⁠ to perform Cloudflare operations
• Uses the Cloudflare Batch API operation to update all DNS records in a single API call
• Caches Cloudflare DNS records so Cloudflare API only needs to be called when something changes
• Only to 2 API calls per update cycle: one to retrieve current DNS status, and one to perform updates (if needed)

⁠How to use

First, you'll need:

• A Cloudflare API token⁠, and the Zone ID⁠, which can be provided in one of two ways:
  • A .env file which defines:
    • An API_TOKEN environment variable
    • A ZONE_ID environment variable
  • Using Docker secrets, passing the file paths to the secrets to the environment variables API_TOKEN_FILE and ZONE_ID_FILE
• (Optional) a RUN_EVERY environment variable which contains the number of seconds to wait before the next IP check. If not included, checks every 60s.
• A domains.json file which defines an array of DNS names to update:
  • Names should only contain the subdomain part (e.g.: if your zone is mybestcfzone.org and you want to update the bestest subdomain, only add bestest to the array)
  • The root DNS record can be added the same way as in the Cloudflare dashboard, by using @ as the subdomain name

⁠Docker compose (recommended)

1. Create a docker-compose.yml file with the following content:

   services:
     app:
       image: fedeabella/cloudflare-ddns
       container_name: cloudflare-ddns
       env_file: .env
       environment:
         - TZ=America/Montevideo
       read_only: true
       restart: always
       volumes:
         - type: bind
           source: ./config
           target: /app/config
   

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2. Put the .env in the same directory as the docker-compose.yml file and create a ./config directory where the domains.json file will be put. Then run

   docker compose up -d
   

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You can check the docker logs to see if the container is running the script properly:

docker logs cloudflare-ddns

⁠Limitations

This was very much built in a couple afternoons to satisfy my personal needs, so it may not have everything you need. For example:

• Only updates A records
• Only updates IP values in the records, no comments, proxiable values, etc.
• Only works on a single Cloudflare Zone
• Does not create new records, only updates existing ones

If you find something you need, feel free to create an Issue on github⁠ and I might look into it, but no promises.