Images

Goal

Learn how to...

• specify which container image to use for a job
• tailor the execution environment to your needs

Task: Simplify using container images

In the previous exampes, we called apk at the beginning of every job to install Go. This had to be repeated for every job because Go was not present. Choosing an image for a job using the image directive, time is saved by avoiding commands to install required tools. See the official documentation.

Replace the calls to apk with the container image golang:1.19.2.

Afterwards check the pipeline in the GitLab UI. You should see a successful pipeline run.

Hint (Click if you are stuck)

• Remove before_script
• Add image: golang:1.19.2 instead

Solution (Click if you are stuck)

.gitlab-ci.yml:

stages:
- check
- build

lint:
  stage: check
  image: golang:1.19.2
  script:
  - go fmt .

audit:
  stage: check
  image: golang:1.19.2
  script:
  - go vet .

build:
  stage: build
  image: golang:1.19.2
  script:
  - |
    go build \
        -ldflags "-X main.Version=${CI_COMMIT_REF_NAME} -X 'main.Author=${AUTHOR}'" \
        -o hello \
        .
  - ./hello

If you want to jump to the solution, execute the following command:

git checkout upstream/160_gitlab_ci/040_image -- '*'

Bonus: Test different images

Add a job to your pipeline to test different container images. Check how different images offer specialized execution environments:

1. Use python:3 and test running python --version
2. Use node and test running node --version