Gitlab parent-child pipelines

Gitlab parent-child pipeline is a convenient method for multi-module projects.

This is an example for the Java-Spring Boot project.

Benefits

1. Child pipelines are easily adjustable.
2. Child pipelines to have its own configuration, which helps to better understand.
3. Child pipelines work easily with Gitlab CI/CD features for exmaple you can group the similar stages.

Examples

1. Create a parent YAML file called .gitlab-ci.yml at the root of the project.

#parent gitlab-ci

stages:
- trigger-modules

trigger module 1/2:
  stage: trigger-modules
  trigger:
    include: module-one/gitlab-module-one.yml
  only:
    changes:
    - module-one/*

trigger module 2/2:
  stage: trigger-modules
  trigger:
    include: module-two/gitlab-module-two.yml
  only:
    changes:
    - module-two/*

2. Create a child YAML file with the desired name for example gitlab-ci-module-one at the root of the each module.

#child gitlab-ci

image: maven:latest

stages:
- build-package-maven

build-package maven 1/2:
  stage: build-package-maven
  script:
  - mvn compile
  only:
  - master

build-package maven 2/2:
  stage: build-package-maven
  script:
  - mvn clean package
  only:
  - master

Usage

trigger module 1/2:
  stage: trigger-modules
  trigger:
    include: module-one/gitlab-module-one.yml
  only:
    changes:
    - module-one/*

1. trigger module 1/2: we can group the steps for better readability. In this example we have two steps. For example, the number 2 is the total number of steps, and 1 means the first step.

2. include: path/to/module.yml

3. only: changes: this pipeline will trigger when the module changes.

Result

After the files are transferred to the Gitlab CE server, the Gitlab-Runner will run and the result will be as shown below.