Running the relay with Docker

The repository includes a Dockerfile and, in deploy/, a Compose file that puts Caddy in front for automatic HTTPS.

With automatic HTTPS

Requirements: a server with Docker and Compose, ports 80 and 443 reachable from the internet, and a DNS record for your relay's name pointing at the server.

git clone https://github.com/zerobyte-cloud/zerobyte-relay.git
cd zerobyte-relay
npm run app-id                     # without Node on the host, see the end of this page
cd deploy
RELAY_DOMAIN=relay.example.com RELAY_APPS=<app id> docker compose up -d

Compose builds the relay image from the repository, starts it and starts Caddy. Caddy obtains a certificate for RELAY_DOMAIN on first start and renews it. Both containers restart unless stopped.

The Caddyfile has no log directive, so Caddy keeps no access log.

To keep the settings out of your shell history, put them in deploy/.env:

RELAY_DOMAIN=relay.example.com
RELAY_APPS=<app id>,<another app id>

Then docker compose up -d without the variables.

Updating

cd zerobyte-relay
git pull
cd deploy
docker compose up -d --build

Watchers are disconnected during the restart and reconnect on their own.

The image alone

docker build -t zerobyte-relay .
docker run -d --name zerobyte-relay --restart unless-stopped \
  -p 127.0.0.1:8080:8080 \
  -v relay-data:/data \
  -e RELAY_APPS=<app id> \
  zerobyte-relay

Put your own TLS proxy in front of port 8080; see Node.

Image details

The image copies only package.json, LICENSE, NOTICE, bin/ and src/.

Generating an app id without Node on the host

docker run --rm -v "$PWD":/app -w /app node:24-alpine node bin/zerobyte-relay.js app-id