Getting Convox apps working with local .dev domains

example-docker-compose.yml

version: "2"
services:
  web:
    build:
      context: .
    # Found the previous convox init using the 'convox/rails' image doesn't work due to the built-in nginx adding another layer of complexity.  The new init using buildpacks is better.  
    command: bin/rails server -p $$PORT -e $$RAILS_ENV -b 0.0.0.0
    environment:
    - PORT=4001
      # skip out other unimportant env vars
      ...
      # set up the domain you want your container to respond to
    - VIRTUAL_HOST=appname.dev
      # tell the nginx-proxy which port you are exposing.  If exposing only one port it will use that one, or default to port 80, but it's good to be explicit
    - VIRTUAL_PORT=445
    ports:
      # define your external port.  Each app running needs a different port, but if you don't define one, to leave it to Docker, then Convox thinks it's an internal only app.
    - 445:4001/tcp

setup.sh

  
# Get the DNS server running for .dev domains
docker run -d --name dnsmasq -p 53535:53/tcp -p 53535:53/udp --restart always --cap-add=NET_ADMIN andyshinn/dnsmasq --address=/dev/127.0.0.1

# Get your mac resolving .dev domains to the DNS server
echo $'nameserver 127.0.0.1\nport 53535' >/etc/resolver/dev

# Get the nginx-proxy listening on port 80 and picking up on container events
docker run -d -p 80:80 -p 443:443 --name nginx-proxy --restart always -v /var/run/docker.sock:/tmp/docker.sock:ro jwilder/nginx-proxy