3. GitLab CI/CD Components

3.1 .gitlab-ci.yml Configuration File

The .gitlab-ci.yml file defines how to run the CI/CD process. It defines the stages (like build, test, and deploy) and what tasks to perform at each stage.

Key Elements:

Stages: Different phases in your pipeline (e.g., build, test, deploy).
Jobs: Tasks executed in each stage.
Scripts: Commands run by each job.
Dependencies: Specify job dependencies.
Artifacts: Files generated by jobs to be used by later stages.

Typical Stages in .gitlab-ci.yml:

Build: Compiles and builds the source code.
Test: Runs automated tests to verify the code’s functionality and correctness.
Deploy: Deploys the application to a specified environment (e.g., staging, production).

Example Configuration:

stages:
  - build
  - test
  - deploy

build_job:
  stage: build
  script:
    - echo "Building the application..."
    - npm install
    - npm run build

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

deploy_job:
  stage: deploy
  script:
    - echo "Deploying the application..."
    - ./deploy.sh

3.2 GitLab Runners

GitLab Runners execute CI/CD jobs defined in .gitlab-ci.yml. Runners take care of running the different stages of your project, like build, test and deploy.

What They Do: Runners take the instructions from your .gitlab-ci.yml file and execute them. For example, they will run your tests or deploy your code to a server.
Resources: They provide the necessary computing power (like servers or virtual machines) to perform these tasks.
Efficiency: Good management of Runners makes sure that everything runs smoothly and quickly, so your software updates can be delivered reliably and without problems.

3.2.1 GitLab Runners and the Calculator Project

The GitLab Runner will execute the CI/CD jobs defined for our calculator application. For example, when the test_job runs, the runner will execute tests to ensure that the calculator app behaves as expected. This immediate feedback loop is essential for maintaining code quality and reliability in our application.

3.3 Pipeline Visualizations and Reports

GitLab offers tools to help you see how your CI/CD pipelines are doing. These tools show you:

Pipeline Status: You can check if your pipelines are running smoothly or if there are any issues.
Job Outcomes: You can see the results of the individual tasks (jobs) that were run, like whether your tests passed or failed.
Performance Metrics: You can gather data on how fast your pipelines are running and where they might be slowing down.

Why is this important?

Identify Bottlenecks: If something is taking too long, you can find out where the problem is and fix it.
Optimize Workflows: You can improve how your team works together based on what the data tells you.
Continuous Improvement: By regularly looking at these insights, your team can keep getting better at delivering software.

By using features like Analyze > CI/CD analytics, teams can make smart decisions based on real data, helping them improve their development process.

4. Conclusion and Next Steps

By understanding the fundamentals of CI/CD, we are laying the groundwork for effectively managing the development lifecycle of our calculator application. In the next module, we will go into creating our .gitlab-ci.yml file, which will define the CI/CD process for our project.

CI/CD Fundamentals

GitLab CI/CD Components