Why is this rule preventing my GitLab stage from running? - gitlab-ci

Question

In my .gitlab-ci.yml file I have this stage, which uses environment variables in artifacts from a previous stage:
build_dev_containers:
stage: build_dev_containers
variables:
CI_DEBUG_TRACE: "true"
script:
- whoami
…and it outputs the following debug information:
++ DEV_CONTAINERS=true
If I change it by adding the following rule, the stage no longer runs:
rules:
- if: '$DEV_CONTAINERS == "true"'
Any idea what I could be doing wrong?
Not sure if this information adds any value, but just in case:
My previous stage outputs a .env file in its artifacts, and it contains the value
DEV_CONTAINERS=true
Here is the complete file. The powershell script creates package.env in the root path:
image: microsoft/dotnet:latest
variables:
GIT_RUNNER_PATH: 'C:\GitLab'
SCRIPTS_PATH: '.\Lava-Tools\BuildAndDeploy\BuildServer'
stages:
- dev_deploy
- build_dev_containers
dev_deploy:
stage: dev_deploy
tags:
- lava
variables:
GIT_CLONE_PATH: '$GIT_RUNNER_PATH/builds/d/$CI_COMMIT_SHORT_SHA/$CI_PROJECT_NAME'
script:
- 'powershell -noprofile -noninteractive -executionpolicy Bypass -command ${SCRIPTS_PATH}\createdevdeployvars.ps1 -Branch "${CI_COMMIT_REF_NAME}" -ShortCommitHash "${CI_COMMIT_SHORT_SHA}"'
artifacts:
reports:
dotenv: package.env
build_dev_containers:
stage: build_dev_containers
image: docker.repo.ihsmarkit.com/octo/alpine/build/dotnet:latest
tags:
- lava-linux-containers
variables:
CI_DEBUG_TRACE: "true"
script:
- whoami
rules:
- if: '$DEV_CONTAINERS == "true"'

Answer 1

The rules are evaluated before the jobs begin, so a rule cannot evaluate the output from a job.
As a workaround I used if statements in my script: section:
build_dev_containers:
stage: build_dev_containers
image: docker.repo.ihsmarkit.com/octo/alpine/build/dotnet:latest
tags:
- lava-linux-containers
script:
- if [ "$DEV_CONTAINERS" == "true" ]; then echo "DEV_CONTAINERS is true - running"; else echo "DEV_CONTAINERS is not true - skipping"; exit 0; fi
- whoami
deploy_dev_containers:
stage: deploy_dev_containers
tags:
- lava
script:
- |
if ( "$DEV_CONTAINERS" -eq "true" ) {
Write-Output "DEV_CONTAINERS is true - running"
}
else {
Write-Output "DEV_CONTAINERS is not true - skipping"
exit 0
}
- ls