Scriptblocks

Goal

Learn how to...

• Use before_script and after_script
• Separate preparation and cleanup commands from core functionality

Task: Separate script blocks into preparation and main task

Commands are currently specified using the script directive. These commands consist of preparation, core functionality and (possibly) cleanup.

To improve readability, move the preparation of the execution environment to a before_script. See the official documentation.

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

Hint (Click if you are stuck)

Move calls to apk to the before_script.

Solution (Click if you are stuck)

.gitlab-ci.yml:

stages:
- check
- build

lint:
  stage: check
  before_script:
  - apk update
  - apk add go
  script:
  - go fmt .

audit:
  stage: check
  before_script:
  - apk update
  - apk add go
  script:
  - go vet .

build:
  stage: build
  before_script:
  - apk update
  - apk add go
  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/030_script_blocks -- '*'

Cleanup commands can be move to after_script (official documentation) but we have no use for this in the current example.

Bonus 1: When after_script is executed

Add commands to all three script block before_script, script and after_script. Test two scenarios:

1. The pipeline succeeds
2. The pipeline failes

What happens to the code in after_script?

Solution (Click to reveal)

Command in after_script are always executed even if the job fails.

This can be very useful for cleaning up.

Bonus 2: What happens to environment variables in script blocks?

Define environment variables in all three script blocks and display them in the same and in the following script block.

When are environment variables available?

Solution (Click to reveal)

Commands in before_script and script share a shell session. Environment variables are available throughout these script blocks.

Commands in after_script are executed in a new shell session. Environment variables defined in before_script and script are gone.