Set CI/CD variables depending on environment - gitlab

Question

We have multiple environments (staging, production...) and I don't want to put sentitive informations like database passwords inside the codebase. For this, I want to use environment variables provided by GitLab CI/CD.
However I don't know how to tell GitLab to run a different set of variables depending on my environment.
What I've done so far:
1- Create environments : Via UI (Project => Operations => Environments : Here I created 2 environments, STAGING and PRODUCTION
2- Create variables Via UI (Project => Settings => CI/CD => Variables : Here I created the variable DB_PASSWORD twice (with of course different values assigned) , one with environment scope set to STAGING, the other one to PRODUCTION.
Now what I want to do is run my project's pipeline. So I go to Project => CI/CD => Pipelines => Run Pipeline and here I expect GitLab CI to ask me if I would like to run my pipeline with the set of variables set for STAGING or PRODUCTION but it doesn't.
How I am supposed to tell GitLab that I want to run my pipeline using DB_PASSWORD variable with the value corresponding to the environment I want to target?

Answer 1

You need to specify the environment in your gitlab-ci.yml file, see here
Example from official gitlab docs:
stages:
- test
- build
- deploy
test:
stage: test
script: echo "Running tests"
build:
stage: build
script: echo "Building the app"
deploy_staging:
stage: deploy
script:
- echo "Deploy to staging server"
environment:
name: staging
url: https://staging.example.com
only:
- master
In this example when running deploy_staging the environment is set to staging and thus you can access the defined Variables for the environment, like so:
deploy_staging:
stage: deploy
script:
- echo "Deploy to staging server"
environment:
name: staging
url: https://staging.example.com
variables:
DB_PASS: ${DB_PASSWORD} # which is your defined variable within Gitlab CI
only:
- master