GitLab Docker in Docker with Postgres

NOTE: If you just need to build docker in a GitLab Pipeline, you should use Kaniko instead of DIND.

I’m embarrassed this took me longer than expected, but here is a .gitlab-ci.yml that will fire up Docker in Docker (so you can build and run containers) and run Postgres to use in your contract tests.

image: docker:stable

stages:
- build
- test

# When using dind, it's wise to use the overlayfs driver for
# improved performance.
variables:
  DOCKER_DRIVER: overlay2

services:
- docker:dind

# These are here just for info purposes (login is needed for GitLab registry)
before_script:
- docker version
- docker info
- docker login registry.gitlab.com -u $GITLAB_USERNAME -p $GITLAB_TOKEN

# This is where we build our image, and tag it with the git commit hash, then push to GitLab registry
build:
  stage: build
  script:
    - docker build -t $GITLAB_IMAGE_NAME:$CI_COMMIT_SHA -t $GITLAB_IMAGE_NAME:latest .
    - docker run --rm $GITLAB_IMAGE_NAME:$CI_COMMIT_SHA npm run lint
    - docker push $GITLAB_IMAGE_NAME:$CI_COMMIT_SHA
    - docker push $GITLAB_IMAGE_NAME:latest

# Run contract tests
contract:
  variables:
    DATABASE_URL: postgres://postgres@postgres/postgres
  stage: test
  script:
    - docker run -d -e POSTGRES_DB -e POSTGRES_USER -e POSTGRES_PASSWORD --name postgres postgres:9.6
    - docker pull $GITLAB_IMAGE_NAME:$CI_COMMIT_SHA
    - docker run --rm -e DATABASE_URL --link postgres $GITLAB_IMAGE_NAME:$CI_COMMIT_SHA npm run contract

In this config, I have some environment variables configured in the gitlab.com UI.

• GITLAB_IMAGE_NAME: Something like registry.gitlab.com/project/repo
• GITLAB_USERNAME: Your username on GitLab
• GITLAB_TOKEN: A token you can generate at https://docs.gitlab.com/ee/user/profile/personal_access_tokens.html

You’ll notice, after I build, I run npm run lint in the container, then after PG is started, we run npm run contract. These are scripts declared in your package.json file.

For the curious, my Dockerfile is

FROM node:10-alpine

RUN apk update && \
    apk upgrade && \
    mkdir /src

# I used pm2 for process management
RUN npm i -g pm2

# If you use any private repos, then you'll need this
#ARG NPM_TOKEN
#RUN echo "//registry.npmjs.org/:_authToken=${NPM_TOKEN}" > src/.npmrc

COPY package.json package-lock.json src/
ARG NODE_ENV
RUN cd src/ && npm install

COPY . src/

WORKDIR src/

EXPOSE 3000
CMD [ "pm2-runtime", "start", "process.yml" ]