GITLAB-CI - Join network created by docker-compose

Question

I am creating a gitlab-ci to run e2e tests over my application, so, given I have this docker-compose.yml:

services:
  chrome:
    image: zenika/alpine-chrome:latest
    command: [
      chromium-browser,
      "--headless",
      "--no-sandbox",
      "--disable-gpu",
      "--ignore-certificate-errors",
      "--reduce-security-for-testing",
      "--remote-debugging-address=0.0.0.0",
      "--remote-debugging-port=9222",
      "https://google.com/",
    ]
    ports:
      - "9222:9222"
    networks:
      - test-e2e

networks:
  test-e2e:
    ipam:
      driver: default
      config:
        - subnet: 172.28.0.0/16

when I run docker-compose up everything just works fine, and on my local machine I am able to visit localhost:9222 and access the chrome debugger.

---

However, when I run the same job on gitlab-ci I get a ECONNREFUSED error:

F---F

Failures:

1) Scenario: List of Profiles # src/features/profile.feature:3
   ✖ Before # dist/node/development/webpack:/hooks/puppeteer.hooks.ts:17
       Failed to fetch browser webSocket url from http://localhost:9222/json/version: connect ECONNREFUSED 127.0.0.1:9222
       Error: connect ECONNREFUSED 127.0.0.1:9222
           at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1191:14)

---

So it is clear that I cannot join the docker-compose network and access localhost:9222 from the job

My gitlab-ci.yml is pretty straightforward and looks like this:

E2E tests:
  stage: test end-to-end
  image:
    name: docker/compose:1.24.1
    entrypoint: ["/bin/sh", "-c"]
  services:
    - docker:dind
  before_script:
    - apk --update add nodejs yarn
    - docker-compose -f test-e2e.yaml up -d
  script:
    - yarn test:cucumber
  after_script:
    - docker-compose -f test-e2e.yaml down

yarn test:cucumber basically runs cucumber and puppeteer trying to access localhost:9222 to get chrome's metadata.

---

How can I join the network created by docker-compose from the gitlab-ci job?

• I don't have access to edit runner configurations

Answer 1

TL; DR On CI your chrome container is reachable using docker:9222 (or more generally <name-of-the-dind-service-on-ci>:<exposed-port>), not localhost:9222

Explanation

As per your gitlab-ci.yml, you will start 2 containers:

• a docker/compose:1.24.1 container from which you will run docker-compose and yarn commands
• a docker:dind on which a Docker Daemon will run. This container will be reachable from docker/compose:1.24.1 container via hostname docker (see GitlabCI doc on accessing services)

When running a container in Docker, the container is actually started by the Docker daemon and will run and expose ports on the host on which the Daemon is running.

• On your machine, the Docker daemon is running locally and will expose the container ports on your local network, allowing you to reach your chrome container via localhost
• On the CI, you are running your commands from a docker/compose:1.24.1 container but the Docker daemon is running in another container (a different host): the docker:dind container. chrome container will be created inside docker:dind container and its port exposed from this same container. You simply need to access the docker:dind container which will expose chrome ports.

By using localhost from your docker/compose:1.24.1 container, you won't be able to reach chrome because its port is not exposed on docker/compose:1.24.1 container but from docker:dind container. You need to specify its host (docker) and the exposed port (9222)