DEV Community

Alex Aslam
Alex Aslam

Posted on

1

CI/CD for Monorepos: Taming the Beast with Smart Strategies 🚀

Hey there, fellow developer! 👋 Let's talk about something that sounds intimidating but doesn’t have to be: managing CI/CD for monorepos. Imagine your codebase as a bustling city—each project is a neighborhood, and CI/CD is the public transit system keeping everything running smoothly. But when one road closes, you don’t shut down the whole city, right? Let’s explore how to keep your monorepo efficient, scalable, and sane.


Why Monorepos? (And Why CI/CD Gets Tricky 🧩)

Monorepos are like a shared workspace for your projects:

  • Pros: Unified dependencies, cross-project refactors, and streamlined collaboration.
  • Cons: A single commit can trigger chaos if CI/CD isn’t optimized.

The Challenge:

  • Over-testing: Rebuilding everything on every change.
  • Dependency Hell: "Wait, which service uses this library?"
  • Slow Pipelines: Your CI becomes a bottleneck.

Strategies to Keep Your Monorepo CI/CD Lean

1. Affected Projects: Build Only What’s Changed

Tools like Nx, Turborepo, or Bazel detect which projects are impacted by a commit. Think of it as GPS for your code:

# Using Turborepo to run tests for affected apps  
npx turbo run test --filter=my-app  
Enter fullscreen mode Exit fullscreen mode

How it works:

  • Track file changes → map to projects → run targeted tasks.
  • No more rebuilding the universe for a typo fix!

2. Cache Everything (Seriously, Everything)

Caching is your monorepo’s best friend:

  • Dependency Caching: Reuse node_modules or .m2 folders.
  • Build Artifacts: Cache Docker layers, compiled binaries, etc.

GitHub Actions Example:

- name: Cache node_modules  
  uses: actions/cache@v3  
  with:  
    path: apps/*/node_modules  
    key: ${{ runner.os }}-node-${{ hashFiles('yarn.lock') }}  
Enter fullscreen mode Exit fullscreen mode

3. Dependency Management: Share Smarter, Not Harder

  • Shared Libraries: Version them internally (e.g., @myorg/utils).
  • Lock Files: Use yarn.lock or package-lock.json to avoid dependency drift.
  • Automated Bumps: Tools like Renovate or Dependabot keep libs fresh.

4. Deployment: Ship the Right Neighborhood

Only deploy services that actually changed:

# Use git to detect modified apps  
git diff --name-only HEAD^ | grep 'apps/' | cut -d/ -f2 | uniq  
Enter fullscreen mode Exit fullscreen mode

Pro Tip: Tag services with [deploy:service-name] in commit messages for manual control.


Tools of the Trade 🛠️

  • Nx/Turborepo: For affected projects and task orchestration.
  • Bazel: Google-grade build system for monorepos.
  • Lerna/Yarn Workspaces: Manage dependencies across projects.
  • CircleCI/GitLab CI: Built-in monorepo optimizations.

Real-World Example: The Startup That Nailed It

A 10-person startup used Turborepo + GitHub Actions to:

  • Reduce build times from 20 minutes → 2 minutes using caching.
  • Deploy only affected microservices (saving cloud costs).
  • Standardize tooling across 15+ projects.

Pitfalls to Avoid

  • The "Kitchen Sink" Monorepo: Don’t shove unrelated projects together.
  • Ignoring Flaky Tests: Quarantine them before they infect your pipeline.
  • Over-Engineering: Start simple. You don’t need Bazel for 3 projects.

Best Practices for Happy Monorepos

  1. Keep CI Configs Modular: Split by project or service.
  2. Monitor Pipeline Health: Track metrics like build time and cache hit rate.
  3. Document Everything: Onboard new devs with a clear monorepo playbook.

Final Thought: Monorepos Don’t Have to Be Scary

With the right strategies, your monorepo can feel like a well-oiled machine—not a ticking time bomb. Focus on smart testing, aggressive caching, and targeted deployments, and you’ll ship code faster, cheaper, and with fewer headaches.

Got a monorepo war story or pro tip? Share it below—let’s learn together! 💬

AWS Q Developer image

Build your favorite retro game with Amazon Q Developer CLI in the Challenge & win a T-shirt!

Feeling nostalgic? Build Games Challenge is your chance to recreate your favorite retro arcade style game using Amazon Q Developer’s agentic coding experience in the command line interface, Q Developer CLI.

Participate Now

Top comments (2)

Collapse
 
taha_ali_31d42c4f58d595c0 profile image
Taha ali

Thanks for this comprehensive breakdown! 🚀

Managing CI/CD for monorepos can definitely feel overwhelming, especially as the codebase scales and the number of projects grows.

I really like the approach of using tools like Nx or Turborepo to run tasks only on affected projects — it’s such a game-changer for build time optimization and resource saving.

Caching everything aggressively is also crucial. We've seen huge improvements in pipeline speed just by properly caching node_modules and build artifacts.

One challenge we faced was managing flaky tests that would occasionally break the pipeline and slow down releases. We found isolating those tests and running them separately helped keep the main pipeline stable.

Would love to hear more about how others handle dependency management at scale in monorepos, especially across multiple teams.

Collapse
 
alex_aslam profile image
Alex Aslam

Thanks so much for sharing your experience—love hearing how others are tackling monorepo challenges! 🙌 Totally agree: tools like Nx and Turborepo are game-changers for slicing through build times. And flaky tests? Ugh, the silent killers of pipeline sanity 😅. Isolating them is such a smart move—we’ve had luck with ‘quarantine’ pipelines too!

Dependency management across teams is a huge topic (and pain point). We’ve seen teams use:

  • Internal package registries (e.g., Verdaccio for npm, Artifactory) to version shared libs.
  • Automated dependency bots (Renovate/Dependabot) with monorepo-aware rules.
  • ‘Golden’ lockfiles enforced via CI to prevent drift.

Would you/others find a deep dive on dependency strategies helpful? Let me know—I’d love to explore this in a future post! 🚀 Keep crushing it!

👋 Kindness is contagious

Take a moment to explore this thoughtful article, beloved by the supportive DEV Community. Coders of every background are invited to share and elevate our collective know-how.

A heartfelt "thank you" can brighten someone's day—leave your appreciation below!

On DEV, sharing knowledge smooths our journey and tightens our community bonds. Enjoyed this? A quick thank you to the author is hugely appreciated.

Okay