22. Foundation of CI/CD: Version Control with Cloud Source Repositories

Introduction: First Step into CI/CD on Google Cloud

In the previous article, we explored the principles of CI/CD—how frequent code changes, automated builds, and testing can transform your development process. Today, we're starting our hands-on journey into implementing those principles using the power of Google Cloud Platform. It begins with one of the most fundamental tools: version control.

The Problem with Unmanaged Code

Imagine working on a project where multiple developers are making changes without a coordinated system. Code conflicts would be a nightmare, tracking what changed when would be near impossible, and going back to an earlier working version would be a major headache. That's where Version Control Systems come in.

Version Control Systems (VCS)

A Version Control System (VCS) is a software tool that acts as a detailed 'history book' for your code. It meticulously tracks every code change, allowing developers to collaborate without fear of overwriting each other's work. VCS also provides the ability to experiment safely within isolated development "branches" before carefully merging new features into the main project. The most popular VCSs are Git, Bitbucket, and Google Cloud's native tool, Cloud Source Repositories.

Git: The Industry Standard

Git has become the most widely used VCS due to its speed, flexibility, and distributed nature. While learning Git can take some time, understanding the basics is crucial for success in CI/CD.

Core Git Concepts

• Repositories: The Heart of Git

  • Think of a repository as a special folder that tracks your entire project's history. It stores not just your code files, but also a record of every change made along the way.

  • Repositories can exist on your local computer or remotely on a service like Cloud Source Repositories.

• Commits: Snapshots of Your Code

  • When you reach a meaningful point in your development (a working feature, a bug fix, etc.), you create a "commit." This is like taking a snapshot of your project at that exact moment.

  • Each commit has a unique ID and a message describing the changes made.

• Branches: Parallel Development Tracks

  • A "branch" is a copy of your codebase that diverges from the main line of development.

  • This allows you to work on new features or experiments without disrupting the main working version. You could have a "development" branch for ongoing changes and a stable "production" branch.

• Merging: Bringing Changes Together

  • Once work on a branch is complete, you merge it back into the main branch.

  • Git helps manage this process, and will try to resolve any conflicts that might occur (when the same code is changed in both branches).

Cloud Source Repositories: Git, the GCP Way

Cloud Source Repositories (CSR) is GCP's fully managed Git repository hosting service. Think of it as a secure and highly available home for your project's code, accessible from anywhere. Here's why CSR shines:

• GCP Integration: CSR works seamlessly with other GCP tools like Cloud Build (for CI/CD pipelines), Cloud IAM (for managing access control), and Cloud Logging (for auditing).

• Simple Setup: Creating repositories within your Google Cloud projects is straightforward, eliminating the need for separate server management.

• Mirroring Capability: CSR can mirror external Git repositories from GitHub or Bitbucket, simplifying migration or multi-cloud scenarios.

• Familiar Git Experience: If you know Git basics, using CSR feels natural.

Let's Get Practical: Creating a CSR Repository

1. Navigate to Cloud Source Repositories: In your GCP console, find the "Cloud Source Repositories" section (https://source.cloud.google.com/).

2. Create a new repository: Provide a name, select your project (if applicable), and click "Create."

3. Get Connected: CSR will display two options: "Connect an existing Git repo" or "Create a new Git repo." and provide needed instructions on each.

Basic Git Workflow with CSR

Let's demonstrate the core actions for interacting with your CSR repository:

1. Initializing a Local Git Repository (if not done already): Use the git init command in your project's root directory.

2. Adding Files: Stage changes for a commit using git add <file1> <file2> ...

3. Committing Changes: Create a snapshot with git commit -m "Your Commit Message"

4. Connecting Your Remote: Link your local repository to CSR using the provided instructions (usually involves the git remote add command).

5. Pushing to CSR: Send your commits using git push origin <branch-name> (usually git push origin main for the main branch).

Cloud Source Repositories offers even more power for your CI/CD workflows:

• Branching and Permissions: Fine-grained control over who can access and modify different branches of your code.

• Automatic Mirroring: Keep CSR in sync with external repositories (GitHub, Bitbucket, etc.) for easy migrations.

• Built-in Code Search and Review: Find what you need and collaborate on code changes within the CSR interface.

CI/CD in Action: The Power of a Push

CI/CD pipelines are often triggered by code changes. Each git push you make to a specific branch on CSR can automatically kick off a build, run tests, and eventually deploy your application. We'll dive deeper into this powerful automation in upcoming articles.