DevOps: How to set up a GitLab CI/CD Pipeline?

1stages:
2  - build
3  - test
4  - deploy_staging
5  - deploy_production
6
7cache:
8  key: ${CI_COMMIT_REF_SLUG}
9  paths:
10    - node_modules/
11
12build:
13  stage: build
14  image: node:18
15  script:
16    - npm ci
17    - npm run build
18  artifacts:
19    paths:
20      - dist/
21    expire_in: 1 hour
22
23test:unit:
24  stage: test
25  image: node:18
26  script:
27    - npm ci
28    - npm run test:unit
29  coverage: '/Lines\s*:\s*(\d+\.\d+)%/'
30
31build:docker:
32  stage: build
33  image: docker:24
34  services:
35    - docker:24-dind
36  before_script:
37    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
38  script:
39    - docker build -t $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA .
40    - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
41
42deploy_staging:
43  stage: deploy_staging
44  script:
45    - kubectl set image deployment/myapp myapp=$CI_REGISTRY_IMAGE:$CI_COMMIT_SHA -n staging
46  environment:
47    name: staging
48    url: https://staging.myapp.com
49  only:
50    - develop
51
52deploy_production:
53  stage: deploy_production
54  script:
55    - kubectl set image deployment/myapp myapp=$CI_REGISTRY_IMAGE:$CI_COMMIT_SHA -n production
56  environment:
57    name: production
58    url: https://myapp.com
59  when: manual
60  only:
61    - main