docker-compose.varnish.yml

version: '3.6'

services:
  # This is the service name used when running ddev commands accepting the
  # --service flag.
  varnish:
    # This is the name of the container. It is recommended to follow the same
    # name convention used in the main docker-compose.yml file.
    container_name: ddev-${DDEV_SITENAME}-varnish
    # Use "varnish:latest" to get the latest stable image.
    image: varnish:6.4
    # These labels ensure this service is discoverable by ddev.
    labels:
      com.ddev.site-name: ${DDEV_SITENAME}
      com.ddev.approot: $DDEV_APPROOT
    environment:
      # This defines the host name the service should be accessible from. This
      # will be sitename.ddev.site.
      # This is the first half of the trick that puts varnish "in front of" the
      # web container, just by switching the names.
      - VIRTUAL_HOST=$DDEV_HOSTNAME
      # This defines the ports the service should be accessible from at
      # sitename.ddev.site.
      - HTTPS_EXPOSE=443:80,8026:8025
      - HTTP_EXPOSE=80:80,8025:8025
    volumes:
      # This exposes a mount to the host system `.ddev/varnish` directory where
      # your default.vcl should be.
      - "./varnish:/etc/varnish"
      - ".:/mnt/ddev_config"
    links:
      - web:web
  # This is the second half of the trick that puts varnish "in front of" the web
  # container, just by switching the names.
  web:
    environment:
      - VIRTUAL_HOST=novarnish.$DDEV_HOSTNAME