Using Gitlab Ci | Devops | Linux Tutorial

Introduction to GitLab CI

GitLab CI (Continuous Integration) is a robust platform that allows developers to automatically build, test, and deploy their code. This tutorial will guide you through the process of setting up and using GitLab CI from start to finish.

Setting Up a New GitLab Project

First, you need to create a new project in GitLab. Follow these steps:

Log in to your GitLab account.
Click on the 'New Project' button.
Fill in the project details and click 'Create project'.

Creating the .gitlab-ci.yml File

The .gitlab-ci.yml file is where you define your CI/CD pipeline. Create this file in the root of your project directory. Here is a basic example:

stages:
  - build
  - test

build_job:
  stage: build
  script:
    - echo "Compiling the code..."

test_job:
  stage: test
  script:
    - echo "Running unit tests..."

This configuration defines two stages: build and test. Each stage has a corresponding job that runs a specified script.

Adding Runners to Your Project

GitLab Runners are agents that run the jobs defined in your .gitlab-ci.yml file. To add a runner:

Go to your project's settings in GitLab.
Navigate to the 'CI / CD' section.
Under the 'Runners' section, click 'Enable shared runners'.
You can also register a specific runner for your project by following the instructions provided under 'Set up a specific Runner manually'.

Running Your First Pipeline

After setting up your .gitlab-ci.yml file and adding runners, push your changes to the repository. GitLab will automatically detect the .gitlab-ci.yml file and trigger the pipeline.

You can view the pipeline status by navigating to the 'CI / CD' > 'Pipelines' section in your project.

Advanced Pipeline Configuration

GitLab CI allows for advanced configurations, including:

Environment Variables: Define variables in the .gitlab-ci.yml file or in the GitLab UI to manage sensitive information.
Artifacts: Use artifacts to pass data between jobs or to store build results.
Caching: Cache dependencies to speed up your pipeline.

Here is an example that includes these advanced features:

stages:
  - build
  - test
  - deploy

variables:
  TEST_VAR: "This is a test variable"

build_job:
  stage: build
  script:
    - echo "Building the project..."
  artifacts:
    paths:
      - build/

test_job:
  stage: test
  script:
    - echo "Running tests with $TEST_VAR"
  cache:
    paths:
      - node_modules/

deploy_job:
  stage: deploy
  script:
    - echo "Deploying the project..."

Debugging and Troubleshooting

If something goes wrong, GitLab CI provides detailed logs for each job. To view the logs:

Navigate to 'CI / CD' > 'Pipelines'.
Click on the pipeline that failed.
Select the job that you want to inspect.
Review the logs to identify the issue.

Common issues include syntax errors in the .gitlab-ci.yml file and missing dependencies. Make sure to read the error messages carefully and refer to the GitLab CI documentation for further assistance.

Conclusion

Congratulations! You have successfully set up and run a GitLab CI pipeline. This tutorial covered the basics of GitLab CI, from creating a project to defining a CI/CD pipeline and running it. With this knowledge, you can now explore more advanced features and customize your pipelines to fit your project's needs.

Using GitLab CI - Comprehensive Tutorial