Run postgreSQL gitlab docker - postgresql

Question

I'm trying to run a pipeline on gitlab of a python webapp made with Django, that uses a postgre database. After installing postgre, the psql command gives the error:
psql: error: could not connect to server: No such file or directory
Here's (part of) my .gitlab-ci.yml file:
image: python:latest
# Install postgreSQL service on container
services:
- postgres:12.2-alpine
# Change pip's cache directory to be inside the project directory
variables:
PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
DJANGO_SETTINGS_MODULE: "my_app.settings"
POSTGRES_DB: $POSTGRES_DB
POSTGRES_USER: $POSTGRES_USER
POSTGRES_PASSWORD: $POSTGRES_PASSWORD
POSTGRES_HOST_AUTH_METHOD: trust
# Let's cache also the packages
# Install packages in a virtualenv and cache it as well
cache:
paths:
- .cache/pip
- venv/
before_script:
- pip install virtualenv --upgrade pip
- virtualenv venv
- source venv/bin/activate
- apt-get update
#- apt-get install -y postgresql postgresql-client libpq-dev # postgre db requirements
stages: # List of stages for jobs, and their order of execution
- build
- verify
- unit_test
- integration_test
- package
- release
- deploy
build:
stage: build
script:
- pip install -r requirements.txt
- echo "Build stage finished"
verify:
stage: verify
script:
- prospector -X ./my_app # static code analysis
- bandit -r ./my_app # static code analysis pt. 2
- echo "Verify stage finished"
unit_test:
stage: unit_test
script:
- echo "Running unit_test 1"
- pytest ./my_app/unit_test.py #running unit_test
- echo "Creating db"
- apt-get install -y postgresql postgresql-client libpq-dev # postgre db
- psql -U postgres
- psql -d "CREATE USER $POSTGRES_USER WITH PASSWORD $POSTGRES_PASSWORD CREATEDB;"
- psql -d "CREATE DATABASE $POSTGRES_DB OWNER $POSTGRES_USER;"
- echo "Unit testing stage finished"
How can I make psql work on gitlab CI/CD pipeline?

Answer 1

You're on the right track with the "services" keyword, which will cause a postgres database to run on the host "postgres" (the DNS of the service is based on the name of the container unless you specify an "alias" with the service).
Your issue is that psql attempts to connect to localhost unless you specify otherwise, so your psql -U postgres attempts to connect on localhost. Try using psql -U postgres -p 5432 -h postgres instead.