GitLab Basics: Repos, Merge Requests & CI Integration

In this tutorial, you'll learn about GitLab Basics: Repos, Merge Requests & CI Integration. We cover key concepts, practical examples, and best practices.

GitLab provides source code management, CI/CD pipelines, and container registry as an integrated DevOps platform available as SaaS or self-hosted.

In this tutorial, you'll learn GitLab fundamentals for managing code repositories, collaborating via merge requests, and integrating CI/CD pipelines. GitLab is a complete DevOps platform — not just Git hosting, but also CI/CD, container registry, and deployment. By the end, you'll create projects, use merge requests, and configure pipelines.

flowchart TD
  A[Create GitLab project] --> B[Clone locally]
  B --> C[Create feature branch]
  C --> D[Push changes]
  D --> E[Create merge request]
  E --> F[CI pipeline runs]
  F --> G{All checks pass?}
  G -->|No| H[Fix and push]
  H --> F
  G -->|Yes| I[Request review]
  I --> J{Approved?}
  J -->|No| K[Address feedback]
  K --> I
  J -->|Yes| L[Merge]

Creating a GitLab Project

GitLab calls repositories projects. Create one via UI or CLI:

# Using GitLab CLI (glab)
glab project create my-project --public

# Or use standard Git workflow
mkdir my-project && cd my-project
git init
git remote add origin https://gitlab.com/your-username/my-project.git
git add .
git commit -m "Initial commit"
git push -u origin main

GitLab Merge Requests

Merge requests are GitLab's equivalent of GitHub pull requests:

# Create a feature branch
git checkout -b feat/user-auth

# Make changes and push
echo "auth code" > auth.py
git add auth.py
git commit -m "feat(auth): add user authentication"
git push -u origin feat/user-auth

On GitLab, create a merge request from the branch. MRs include:

• Description with templates
• Linked issues (using Closes #42)
• Related merge requests
• Pipeline status
• Approval tracking

CI/CD Integration

GitLab CI/CD is built in — every project has pipelines. Create .gitlab-ci.yml:

stages:
  - test
  - build
  - deploy

test:
  stage: test
  image: python:3.11
  script:
    - pip install -r requirements.txt
    - pytest
  artifacts:
    reports:
      junit: report.xml

build:
  stage: build
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker build -t my-app .
  only:
    - main

Code Review with Merge Requests

GitLab's merge request workflow includes:

GitLab Container Registry

Every project has a built-in container registry:

# Login to GitLab container registry
docker login registry.gitlab.com

# Build and push
docker build -t registry.gitlab.com/your-username/my-project:latest .
docker push registry.gitlab.com/your-username/my-project:latest

# Use in CI
image: registry.gitlab.com/your-username/my-project:latest

GitLab Pages

Deploy static sites from GitLab:

pages:
  stage: deploy
  script:
    - mkdir .public
    - cp -r * .public/
    - mv .public public
  artifacts:
    paths:
      - public
  only:
    - main

Comparison: GitLab vs GitHub

Common Errors

Practice Questions

Challenge

Create a GitLab project with a Python application. Configure CI/CD with three stages: lint (flake8), test (pytest with coverage), and build (Docker image). Push the code and verify the pipeline runs. Create a merge request from a feature branch, add a reviewer, and complete the merge.

Real-World Task

Set up a GitLab project with the complete DevOps workflow: (1) Create project with README and license, (2) Configure CI/CD with test, lint, and deploy stages, (3) Set up the container registry and push a Docker image, (4) Configure GitLab Pages for documentation, (5) Set up merge request approvals requiring at least 2 reviewers. This mirrors how DodaTech manages internal projects on self-hosted GitLab for tools like DodaZIP.

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