How to use Gitlab CI/CD to build your image automatically

In this section you'll learn how to leverage CI/CD pipilines in INFN baltig (or any other gitlab instance) in order to automatically build your images and to push them to the gitlab container registry.

Requirements

• baltig.infn.it account and access
• gitlab CLI:

  wget https://gitlab.com/gitlab-org/cli/-/releases/v1.46.0/downloads/glab_1.46.0_Linux_x86_64.deb
  sudo dpkg -i glab_1.46.0_Linux_x86_64.deb
  

• a baltig token with 'api' and 'write_repository' scopes (see below)
• having followed the previous tutorial

Create a git repository with your app

Let's initialize a git repository in our flask dir:

cd flask
git init
git switch -c main
git config --global user.name "Diego Ciangottini"
git config --global user.email "diego.ciangottini@pg.infn.it"

Login in baltig via:

$ glab auth login
? What GitLab instance do you want to log into? GitLab Self-hosted Instance
? GitLab hostname: baltig.infn.it
? API hostname: baltig.infn.it
- Logging into baltig.infn.it
? How would you like to login? Token

Tip: you can generate a Personal Access Token here https://baltig.infn.it/-/profile/personal_access_tokens
The minimum required scopes are 'api' and 'write_repository'.
? Paste your authentication token: ********************
? Choose default git protocol HTTPS
? Authenticate Git with your GitLab credentials? Yes
? Choose host API protocol HTTPS
- glab config set -h baltig.infn.it git_protocol https
✓ Configured git protocol
- glab config set -h baltig.infn.it api_protocol https
✓ Configured API protocol
✓ Logged in as project_4873_bot

Create a pipeline to automatically build your image

Create a file .gitlab-ci.yml with your workflow description:

build_base_image:
  image: docker:latest
  stage: build
  services:
    - docker:dind
  before_script:
    - echo 'docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} baltig.infn.it:4567'
    - docker login -u ${CI_REGISTRY_USER} -p ${CI_REGISTRY_PASSWORD} baltig.infn.it:4567
  # Default branch leaves tag empty (= latest tag)
  # All other branches are tagged with the escaped branch name (commit ref slug)
  script:
    - |
      if [[ "$CI_COMMIT_BRANCH" == "$CI_DEFAULT_BRANCH" ]]; then
        tag=":latest"
        echo "Running on default branch '$CI_DEFAULT_BRANCH': tag = 'latest'"
      else
        tag=":$CI_COMMIT_REF_SLUG"
        echo "Running on branch '$CI_COMMIT_BRANCH': tag = $tag"
      fi
      docker build -t "$CI_REGISTRY_IMAGE${tag}" .
      docker push "$CI_REGISTRY_IMAGE${tag}"

And then commit everything into gitlab that you already created in previous tutorials:

git remote add origin https://baltig.infn.it/ciangottini/tutorial-ci.git
git add .
git commit -m "Initial commit"
git push -u origin main

Warning

Remember to replace ciangottini with your baltig username!!

Monitor the building process

Pipeline monitoring page is available at your repo site like https://baltig.infn.it/ciangottini/tutorial-ci/-/pipelines

Or via CLI:

$ glab ci list
Showing 3 pipelines on ciangottini/tutorial-ci (Page 1)

(running) • #82282  main  (less than a minute ago)
(failed) • #82281   main  (about 4 minutes ago)   
(failed) • #82280   main  (about 7 minutes ago)

and then you can get details via glab ci view #82281. Or you than live tracing the progress log via glab ci trace #82285

Once completed you should be able to see the docker image stored on gitlab registry at something like https://baltig.infn.it/ciangottini/tutorial-ci/container_registry

The container is now ready to be pulled from the registry via: docker pull baltig.infn.it:4567/ciangottini/tutorial-ci

Exercises

• Create a pipeline to periodically build your latest tag

• Push image to dockerHUB instead