services:
  # Custom CoreDNS build with the rfc2136 plugin baked in.
  # The Dockerfile lives in the parent dir (../coredns/Dockerfile) so
  # we reuse the production build artefact.
  coredns:
    build:
      context: ..
      dockerfile: coredns/Dockerfile
    image: coredns-rfc2136-test:dev
    container_name: coredns-rfc2136-test
    restart: "no"  # never auto-restart in test scenarios
    command: ["-conf", "/etc/coredns/Corefile"]
    environment:
      - ACME_TSIG_SECRET=${ACME_TSIG_SECRET}
    ports:
      - "${TEST_DNS_PORT}:53/udp"
      - "${TEST_DNS_PORT}:53/tcp"
      - "${TEST_METRICS_PORT}:9153/tcp"
    volumes:
      - ./Corefile:/etc/coredns/Corefile:ro
      - ./zones:/zones      # NOT read-only: rfc2136 needs to write here
    healthcheck:
      test: ["CMD", "/coredns", "-version"]
      interval: 10s
      timeout: 3s
      retries: 3
      start_period: 5s