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Docker Integration

Roxy can automatically discover Docker Compose services and register them as .roxy domains. When enabled, starting a compose stack instantly makes services available at https://<service>.<project>.roxy.

Enabling Docker Integration

Add the [docker] section to your Roxy user configuration (~/Library/Application Support/Roxy/config.toml on macOS or $HOME/.config/roxy/config.toml on Linux):

[docker]
enabled = true

Then restart the daemon:

roxy restart

Roxy connects to the Docker socket and watches for container lifecycle events. When a container starts or stops, Roxy automatically updates its routing table.

How Auto-Discovery Works

When a container starts, Roxy evaluates it using these rules (in order):

  1. roxy.enable=false label -- skip (explicit opt-out)
  2. roxy.enable=true label -- register (explicit opt-in)
  3. Compose labels + exposed port -- register automatically
  4. Otherwise -- skip

For compose services, the domain is derived from the project and service names: <service>.<project>.roxy. For example, a service named web in project myapp becomes web.myapp.roxy.

Requirements for Auto-Discovery

  • The container must have at least one published port (ports: mapping in docker-compose.yml)
  • Roxy proxies to the host port, not the container port
  • If a container exposes multiple ports, set roxy.port to pick one (see Labels Reference)

Quick Start

Given this docker-compose.yml:

services:
  web:
    build: .
    ports:
      - "3000:3000"
# Enable Docker integration in Roxy config
# (add [docker] enabled = true, then restart)

# Start your compose stack
docker compose up -d

# Roxy auto-discovers and registers web.myproject.roxy
# (project name comes from directory name by default)
open https://web.myproject.roxy

No roxy register needed -- it happens automatically.

Labels Reference

Control Roxy behavior with container labels, either in docker-compose.yml or via docker run --label.

Label Values Description
roxy.enable true / false Force opt-in or opt-out
roxy.domain e.g. app.roxy Override the auto-generated domain
roxy.port e.g. 8080 Pick which container port to proxy
roxy.wildcard true Register as wildcard (*.domain)

Examples

Custom domain:

services:
  web:
    build: .
    ports:
      - "3000:3000"
    labels:
      roxy.domain: "myapp.roxy"

Explicit opt-in (non-compose container):

services:
  standalone:
    image: nginx
    ports:
      - "8080:80"
    labels:
      roxy.enable: "true"
      roxy.domain: "nginx.roxy"

Multiple ports -- pick one:

services:
  api:
    build: .
    ports:
      - "3000:3000"
      - "9090:9090"
    labels:
      roxy.port: "3000"

Wildcard subdomains:

services:
  web:
    build: .
    ports:
      - "3000:3000"
    labels:
      roxy.wildcard: "true"

This registers *.web.myproject.roxy, so anything.web.myproject.roxy routes to the container.

Opt out a service:

services:
  db:
    image: postgres
    ports:
      - "5432:5432"
    labels:
      roxy.enable: "false"

Domain Name Resolution

Roxy determines the domain in this order:

  1. roxy.domain label -- used as-is (must end with .roxy)
  2. Compose labels -- <service>.<project>.roxy

The compose project name defaults to the directory name. You can set it explicitly with COMPOSE_PROJECT_NAME or the name: key in docker-compose.yml:

name: myapp

services:
  web:
    build: .
    ports:
      - "3000:3000"
# Domain: web.myapp.roxy

Container-to-Roxy Communication

When one container needs to reach another container's .roxy domain (or any .roxy domain served by the host), Docker's default DNS won't resolve .roxy names. Use extra_hosts to point the domain at the host:

services:
  web:
    build: .
    ports:
      - "3000:3000"

  worker:
    build: .
    extra_hosts:
      - "web.myproject.roxy:host-gateway"

host-gateway resolves to the host machine's IP (typically host.docker.internal on Docker Desktop). The worker container can now reach http://web.myproject.roxy through Roxy on the host.

Add one entry per .roxy domain the container needs to access.

Note: Wildcard extra_hosts (e.g., *.roxy) are not supported -- /etc/hosts does not allow wildcards. You must list each domain explicitly.

Linux vs macOS

On Linux, Docker containers share the host network namespace (or use a bridge with direct host access). DNS resolution and HTTP connectivity work without extra_hosts in most setups.

On macOS, Docker Desktop runs containers inside a Linux VM. Containers cannot reach the host via its LAN IP, but can reach it via host-gateway / host.docker.internal. The extra_hosts approach above is required for container-to-Roxy communication.

Monitoring

Check which Docker containers Roxy has discovered:

roxy list

Docker-discovered domains show their source as "external" in the output. They appear alongside manually registered domains but cannot be edited with roxy register or roxy route -- they are managed entirely by the Docker watcher.

View discovery logs:

# After setting daemon.log_level = "debug" in the Roxy config
roxy restart

# Or check the log file
roxy logs -f

Example log output:

INFO Docker integration enabled
INFO Docker domain added domain=web.myapp.roxy target=127.0.0.1:3000
INFO Docker reconciliation complete added=1 removed=0 total=1

Troubleshooting

Container Not Discovered

Check that:

  1. Docker integration is enabled ([docker] enabled = true)
  2. The container has published ports (ports: in compose)
  3. The container is not opted out (roxy.enable=false)
  4. The daemon is running (roxy status)

Set daemon.log_level = "debug" in the Roxy config, restart, and follow the log to see why a container was skipped:

roxy restart
roxy logs -f

Look for Docker container skipped messages with a reason.

"No published host port" Error

Roxy needs a host port mapping to proxy traffic. Make sure your service has a ports: entry:

services:
  web:
    build: .
    # This is required:
    ports:
      - "3000:3000"
    # EXPOSE alone is not enough

Multiple Ports Without Label

If a container exposes more than one port and no roxy.port label is set, Roxy skips it (ambiguous). Add the label:

labels:
  roxy.port: "3000"

Docker Socket Permission

Roxy connects to the Docker socket (/var/run/docker.sock by default) as your developer account. If you see connection errors, verify the socket exists and that your account can access it. On Linux this commonly means adding the account to the docker group (then logging in again) or using a rootless Docker socket.