docker-compose host access test

README.md

Run run.sh. Expected output:

test-a_1  | ok host
test-b_1  | ok host.docker.internal:host-gateway
test-c_1  | ok host.docker.internal

docker-compose.yml

version: "3.7"
services:
  listen:
    build: .
    ports:
      - "8888:8888"
    command: bash -c "nc -vkl 8888"
    init: true
  test-a:
    build: .
    extra_hosts:
      - host:host-gateway
    environment:
      - ADDRESS=host
  test-b:
    build: .
    extra_hosts:
      - host.docker.internal:host-gateway
    environment:
      - ADDRESS=host.docker.internal
  test-c:
    build: .
    environment:
      - ADDRESS=host.docker.internal
  test-d:
    build: .
    environment:
      - ADDRESS=listen

Dockerfile

FROM ubuntu
RUN apt-get update
RUN apt-get -y install netcat
CMD nc -zv -w 1 $ADDRESS 8888

run.sh

docker-compose up -d listen; docker-compose up test-{a,b,c}; docker-compose down