Gitlab CI/CD Introduction

Key Concepts

• Gitlab CI/CD: Automation engine for software development (similar to Jenkins).

  • Practices: Continuous integration, Continuous Delivery/Deployment.

• Gitlab Pipeline (CI YAML): Version-controlled .gitlab-ci.yml file at the root directory of a Gitlab project.

  • Components:
    • Job: Describes tasks (e.g., compile, test, deploy code).
    • Stage: Defines the order of jobs.

• Gitlab Runner: Program executing the pipeline jobs; can run on local machines, VMs, or Docker containers.

Creating the First Pipeline

1. Navigate to CI/CD section

• Pipeline section or Pipeline Editor.
• Gitlab provides CI/CD templates for various tech stacks.

2. Using the Pipeline Editor

• Browser-based; provides template and validation.
• Features: Syntax highlighting and keyword suggestions (bug noted).
• Additional Tabs: Visualize (graphical view) and Lint (syntax check).

Structure of a Basic Pipeline

• Stages Section

  • Defines stages in order (e.g., build, test, deploy).
  • Example: stages: [build, test, deploy]

• Job Definition

  • Jobs associated with stages using the stage: keyword.
  • Required keyword: script: for commands.
  • Example: Build job creating a file to be used in Test and Deploy jobs.

Running the Pipeline

• Pipeline Execution
  • Commit changes to trigger the pipeline.
  • Issues related to workspace isolation and artifact sharing.

Artifacts & Sharing Data

• Artifacts Keyword

  • Specifies files to share with downstream jobs.
  • Example: artifacts: { paths: ["build/executable_binary_file_v1"] }

• Adjust Unit Test Job

  • Modify to consume artifact: cat $CI_PROJECT_DIR/build/executable_binary_file_v1
  • Commit changes and check pipeline output (successful reference).

Docker Images

• Using Docker Images
  • Specified using image: keyword.
  • Example: Python Docker image (image: python:latest)
  • Docker container handles script commands.
  • Custom Docker images can be used.

Environment Variables

• Defining Variables
  • Use variables: keyword; specify key-value pairs.
  • Example: variables: { USERNAME: "tech_with_moss" }
  • Sensitive variables: Define in CI/CD Settings -> Variables (e.g., password).

Gitlab Runner Settings

• Shared vs. Specific Runners
  • Shared runners: Hosted by Gitlab, limited free minutes.
  • Specific runners: User-managed compute resources (local/VM/Docker).

Caching

• Cache Keyword
  • Caches files downloaded in a job, reducing redundant downloads.
  • Example: Caching Python packages.

Conclusion

• Quick overview of Gitlab CI/CD and pipeline creation.
• References: Key documentation links included for further reading and video description.