Gitlab CI with Docker images - Flask microservice testing database - postgresql

Question

I am trying to deploy a Flack app/service which is built into a docker container to Gitlab CI. I am able to get everything working via docker-compose except when I try to run tests against the postgres database I am getting the below error:
Is the server running on host "events_db" (172.19.0.2) and accepting
TCP/IP connections on port 5432?
Presumably this is because the containers can't see each other. I've tried many different methods. But below is my latest. I have attempted to have docker-compose spin up both containers (just like it does on local), run the postgres db as a git lab service, run from a python image instead of a docker image, use a docker.prod.yml where I remove the volumes and variables.
Nothing is working. I've checked just about every link that shows up on google when you look for 'gitlab ci docker flask postgres' and I believe that I am massively misunderstanding the implementation.
I do have gitlab runner up and going.
.gitlab-ci.yml
image: docker:latest
services:
- docker:dind
- postgres:latest
stages:
- test
variables:
POSTGRES_DB: events_test
POSTGRES_USER: postgres
POSTGRES_PASSWORD: postgres
DATABASE_URL: postgres://postgres#postgres:5432/events_test
FLASK_ENV: development
APP_SETTINGS: app.config.TestingConfig
DOCKER_COMPOSE_VERSION: 1.23.2
before_script:
#- rm /usr/local/bin/docker-compose
- apk add --no-cache py-pip python-dev libffi-dev openssl-dev gcc libc-dev make
- pip install docker-compose
#- mv docker-compose /usr/local/bin
- docker-compose up -d --build
test:
stage: test
#coverage: '/TOTAL.+ ([0-9]{1,3}%)/'
script:
- docker-compose exec -T events python manage.py test
after_script:
- docker-compose down
docker-compose.yml
version: '3.3'
services:
events:
build:
context: ./services/events
dockerfile: Dockerfile
volumes:
- './services/events:/usr/src/app'
ports:
- 5001:5000
environment:
- FLASK_ENV=development
- APP_SETTINGS=app.config.DevelopmentConfig
- DATABASE_URL=postgres://postgres:postgres#events_db:5432/events_dev # new
- DATABASE_TEST_URL=postgres://postgres:postgres#events_db:5432/events_test # new
events_db:
build:
context: ./services/events/app/db
dockerfile: Dockerfile
ports:
- 5435:5432
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=postgres

Answer 1

What is the executor type of your Gitlab Runner?
If you're using the Kubernetes executor, add this variable:
DOCKER_HOST: tcp://localhost:2375/
For non-Kubernetes executors, we use tcp://docker:2375/
DOCKER_HOST: tcp://docker:2375/
Also, the Gitlab Runner should be in "privileged" mode.
More info:
https://docs.gitlab.com/ee/ci/docker/using_docker_build.html#help-and-feedback
Hope that helps!