GitLab CI — Reusable Job Attributes

Pipelines that can happen with !reference

This feature has been introduced way back in 2020, if I recollect it correct, plus it has some great capabilities especially in the area of parallelization.

A detailed CI Guide is available at the Docs

Lets now understand the re-usability..

Problem Statement

Lets say I have the below script and I want to re-use the code than CTRL+C and CTRL+V

stages:
- build
- test

helm-install:
  stage: build
  image: alpine:latest
  script:
  - apk add --no-cache git wget curl
  - wget -q https://get.helm.sh/helm-v3.9.4-linux-amd64.tar.gz -O - | tar -xzO linux-amd64/helm > /usr/local/bin/helm
  - chmod +x /usr/local/bin/helm

helm-test:
  stage: test
  image: alpine:latest
  script:
  - helm version --client

Now, installing helm could be done at several places in other jobs, hence “re-usability” is one thing that strikes us.

stages:
- test

.helm-install:
  script:
  - apk add --no-cache git wget curl
  - wget -q https://get.helm.sh/helm-v3.9.4-linux-amd64.tar.gz -O - | tar -xzO linux-amd64/helm > /usr/local/bin/helm
  - chmod +x /usr/local/bin/helm

helm-test:
  stage: test
  image: alpine:latest
  extends: 
  - .helm-install
  script:
  - helm version --client

The problem here is that the script is overriding the section after importing the job template .helm-install.

Solution

The !reference is at rescue where the job attributes in other jobs, as in - !reference [.helm-install, script] so the CI would like as below

stages:
- test

.helm-install:
  script:
  - apk add --no-cache git wget curl
  - wget -q https://get.helm.sh/helm-v3.9.4-linux-amd64.tar.gz -O - | tar -xzO linux-amd64/helm > /usr/local/bin/helm
  - chmod +x /usr/local/bin/helm

helm-test:
  stage: test
  image: alpine:latest
  extends: 
  - .helm-install
  script:
  - !reference [.helm-install, script]
  - helm version --client

AMAZING, right?