Graylog w/ Caddy reverse proxy docker compose YAML file

docker-compose.yml

version: '2'
services:
  # MongoDB: https://hub.docker.com/_/mongo/
  mongodb:
    image: mongo01
    networks:
     - backend
    volumes:
      - graylog01_mongo_data_new:/data/db
  # Elasticsearch: https://www.elastic.co/guide/en/elasticsearch/reference/7.10/docker.html
  elasticsearch:
    image: elasticsearch01
    networks:
      - backend
    volumes:
      - graylog01_es_data_new:/usr/share/elasticsearch/data
    environment:
      - http.host=0.0.0.0
      - transport.host=localhost
      - network.host=0.0.0.0
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
    ulimits:
      memlock:
        soft: -1
        hard: -1
    mem_limit: 1g
  # Graylog: https://hub.docker.com/r/graylog/graylog/
  graylog:
    image: graylog01
    networks:
      - caddy
      - backend
    labels:
      caddy: graylog.domain.foo
      caddy.reverse_proxy: "{{upstreams 9000}}"
    volumes:
      - graylog01_graylog_data_new:/usr/share/graylog/data
    environment:
      # CHANGE ME (must be at least 16 characters)!
      - GRAYLOG_PASSWORD_SECRET=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
      # Password: admin
      - GRAYLOG_ROOT_PASSWORD_SHA2=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
      - GRAYLOG_HTTP_EXTERNAL_URI=https://graylog.domain.foo/
    entrypoint: /usr/bin/tini -- wait-for-it elasticsearch:9200 --  /docker-entrypoint.sh
    links:
      - mongodb:mongo
      - elasticsearch
    restart: always
    depends_on:
      - mongodb
      - elasticsearch
    ports:
      # Graylog web interface and REST API
      # - 9000:9000
      # Syslog TCP
      - 1514:1514
      # Syslog UDP
      - 1637:1637/udp
      # GELF TCP
      - 12201:12201
      # GELF UDP
      - 12201:12201/udp
    expose:
      - 9000
# Volumes for persisting data, see https://docs.docker.com/engine/admin/volumes/volumes/
volumes:
  graylog01_mongo_data_new:
     external: true
  graylog01_es_data_new:
     external: true
  graylog01_graylog_data_new:
     external: true

networks:
  caddy:
    external: true
  backend:
    external: false