Docker Hub RSS

RSS feed for Docker Hub images

Why?

Docker Hub doesn't provide notifications for new image releases, so Docker Hub RSS turns image tags into an RSS feed for easy consumption. Subscribe using Slack RSS, Feedly, or any other RSS feed reader to get notified when a new image is published.

Usage

Point an RSS feed reader at /<docker-hub-user>/<docker-hub-repo>.atom. The bare (/<user>/<repo>) and /r/<user>/<repo> routes serve the same feed, and tags can be filtered with the include, exclude, includeRegex, and excludeRegex query params. Use _ as the user for official images (e.g. /_/nginx.atom).

Running

Docker Hub RSS runs four ways. The Local, Docker, and Vercel paths share the Express app (index.js, api/); Cloudflare runs the equivalent Worker (src/worker.js).

Local (Node)

yarn install
yarn start          # Express on http://localhost:3000

The easiest way to expose a local instance publicly for an RSS reader is to proxy it with Localtunnel.

Docker

docker run -d -p 3000:3000 --name=docker-hub-rss theconnman/docker-hub-rss:latest

Vercel

npm i -g vercel
yarn install
vercel dev          # local; deploy with `vercel` (routing in vercel.json)

Cloudflare Workers

Runs as a single Cloudflare Worker — a free, publicly reachable feed with no server to host. The Worker serves the same routes; the homepage is served from the Wrangler [assets] layer, and each feed is cached at the edge (~30 min TTL) so repeat RSS polls don't re-hit Docker Hub.

yarn install
yarn dev            # wrangler dev — local, no Cloudflare account required
yarn test           # vitest suite (runs in the Workers runtime)
wrangler deploy     # deploy (requires `wrangler login`)

The Worker deploys to *.workers.dev. On the free tier, TAGS_FETCH_LIMIT (a wrangler.toml var, default 100) keeps each request to ~3 Docker Hub subrequests, under the 50-per-request cap.

The deployed Worker requires two secrets — a Docker Hub username and a read-only access token — because Docker Hub rate-limits Cloudflare's shared egress IPs and returns HTTP 429 to anonymous requests; authenticating gives the feed a per-account limit instead:

npx wrangler secret put DOCKERHUB_USERNAME
npx wrangler secret put DOCKERHUB_TOKEN

When the secrets are absent (e.g. wrangler dev or the test suite), the Worker falls back to anonymous requests.

Environment Variables

• FLUENTD_HOST (Optional) Fluent host for logging
• FLUENTD_TAGS (Optional) Add FluentD context tags (format is tag:value,tag2:value2)
• TAGS_FETCH_LIMIT (Optional) Fetch only the given number of tags (before being filtered). Useful for reducing traffic and avoiding possible time-outs.
• PORT (Default: 3000) Port to run the service on

Info Endpoint

/info is helper endpoint which provides additional information about the environment including:

• version: The version number of this Docker Hub RSS instance