How to Use extends and YAML Anchors in GitLab CI/CD

extends merges a hidden template job into a real job, while YAML anchors reuse raw blocks of config.

Define a hidden job (name starting with a dot) and pull it into real jobs with extends:. For smaller fragments, an &anchor and *alias reuses a block directly.

Steps

• Define a hidden template job (e.g. .test-base).
• Use extends: .test-base in real jobs to inherit it.
• Use &anchor/*alias to reuse a small inline block.

Pipeline

.test-base:
  image: node:20
  before_script:
    - npm ci

test-unit:
  extends: .test-base
  script: npm run test:unit

test-e2e:
  extends: .test-base
  script: npm run test:e2e

Gotchas

• extends deep-merges maps key by key, while a YAML alias copies the whole block as-is.
• Hidden jobs (dot-prefixed) never run on their own; they exist only to be extended.

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