Duplicated code in .gitlab-ci.yml's script section

Question

Is there a way within gitlab ci to create something like a function? I would like to don't have the duplicated code in the stages or should I use a external script for such a task?

I had a look into the gitlab template but with a template I can only use a job in the template once.

stages:
  - build-artefakts
  - build-image

variables:
  CI_REGISTRY_NAMESPACE: 'main'
  CI_BASE_IMAGE: '...'

  1_GROUP_ID: '...'
  1_ARTIFACT_ID: '...'
  1_CLASSIFIER: '...'
  1_JAR_NAME: '...'
  1_IMAGE_NAME: '...'

  2_GROUP_ID: '...'
  2_ARTIFACT_ID: '...'
  2_CLASSIFIER: '...'
  2_JAR_NAME: '...'
  2_IMAGE_NAME: '...'


deploy-maven:
  image: maven:3.6-jdk-11
  stage: build-artefakts
  script:
    - 'mvn deploy -f pom.xml -s ~config/maven/ci_settings.xml -P prod'
  only:
    - master
  artifacts:
    paths:
      - ./target
    expire_in: 1 weeks

deploy-docker-1:
  image: $CI_BASE_IMAGE
  stage: build-image
  variables:
    ARTIFACT_ID: $1_ARTIFACT_ID
    JAR_NAME: $1_JAR_NAME
    IMAGE_NAME: $1_IMAGE_NAME

  before_script:
    - 'docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_TOKEN  $CI_REGISTRY'
  script:
    - 'cd docker'
    - 'mv ../target/$ARTIFACT_ID/*.jar $JAR_NAME'
    - 'docker build . -t $IMAGE_NAME:$PROJECT_VERSION --build-arg JAR_FILE=$JAR_NAME'
    - 'docker tag $IMAGE_NAME:$PROJECT_VERSION $CI_REGISTRY/$CI_REGISTRY_NAMESPACE/$IMAGE_NAME:$PROJECT_VERSION'
    - 'docker push $CI_REGISTRY/$CI_REGISTRY_NAMESPACE/$IMAGE_NAME:$PROJECT_VERSION'

deploy-docker-2:
  image: $CI_BASE_IMAGE
  stage: build-image
  variables:
    ARTIFACT_ID: $2_ARTIFACT_ID
    JAR_NAME: $2_JAR_NAME
    IMAGE_NAME: $2_IMAGE_NAME

  before_script:
    - 'docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_TOKEN  $CI_REGISTRY'
  script:
    - 'cd docker'
    - 'mv ../target/$ARTIFACT_ID/*.jar $JAR_NAME'
    - 'docker build . -t $IMAGE_NAME:$PROJECT_VERSION --build-arg JAR_FILE=$JAR_NAME'
    - 'docker tag $IMAGE_NAME:$PROJECT_VERSION $CI_REGISTRY/$CI_REGISTRY_NAMESPACE/$IMAGE_NAME:$PROJECT_VERSION'
    - 'docker push $CI_REGISTRY/$CI_REGISTRY_NAMESPACE/$IMAGE_NAME:$PROJECT_VERSION'

Answer 1

You can use YAML-Anchors in "script"-sections:

.some-script: &some-script
  - echo "executed script"

.some-other-script: &some-other-script
  - echo "executed other script"

first_job:
  script:
    - *some-script

second_job:
  script:
    - *some-other-script

Since GitLab 13.9 you can also use the custom YAML tag !reference:

.some-script:
  script:
    - echo "executed script"

.some-other-script:
  script:
    - echo "executed other script"

first_job:
  script:
    - !reference [.some-script, script]

second_job:
  script:
    - !reference [.some-other-script, script]

The difference between the two approaches is that YAML anchors cannot be used across included YAML files. Referenced tags, on the other hand, can be used across included YAML files.