CI/CD Philosophy

My approach to Continuous Integration and Continuous Deployment emphasizes fail-fast principles, artifact integrity, and clear separation of concerns. Each pipeline stage has a specific purpose, and failures at any stage halt progression to prevent wasted compute and early detection of issues.

Continuous Integration

---
config:
  look: handDrawn
  theme: neutral
---
flowchart LR
  init --> lint --> test --> build --> quality --> push --> finalize

  click init "#ci-init-stage"
  click lint "#ci-lint-stage"
  click test "#ci-test-stage"
  click build "#ci-build-stage"
  click quality "#ci-quality-stage"
  click push "#ci-push-stage"
  click finalize "#ci-finalize-stage"

A CI pipeline starts when code is pushed to a version control server.

CI Init Stage

The init stage is triggered by a git push or pull request event. The pipeline:

  • Checks out the source code
  • Sets up the runtime environment (Node.js, Python, etc.)
  • Restores cached dependencies for faster builds

CI Lint Stage

The lint stage performs static analysis on all files in the repository. This is the first gate because it’s fast and catches common issues immediately:

  • Code style violations - ESLint, Prettier
  • Shell script issues - ShellCheck
  • Dockerfile best practices - Hadolint
  • Type errors - TypeScript compiler

If code doesn’t pass lint, there’s no point running expensive tests or builds.

CI Test Stage

The test stage executes unit tests only. Unit tests are fast, isolated, and don’t require external dependencies. This is not to be confused with:

  • Integration tests - Run in the quality stage after artifacts are built
  • Regression tests - Run in the CD pipeline after deployment

CI Build Stage

The build stage generates deployable artifacts:

  • Compiled applications
  • Docker container images
  • Static site bundles
  • Archive files (tar, zip)

These artifacts are versioned and stored for later stages.

CI Quality Stage

The quality stage validates the built artifacts through:

  • Security scanning - Trivy for CVEs, secrets, misconfigurations
  • Integration tests - End-to-end tests against running containers
  • Dependency audits - npm audit, pip-audit
  • Code quality analysis - SonarQube for bugs, code smells, coverage

This stage runs after build because it needs the actual artifacts to scan and test.

CI Push Stage

The push stage publishes validated artifacts to artifact stores:

  • Container registries (ECR, Docker Hub, GHCR)
  • Package registries (npm, PyPI)
  • Object storage (S3, GCS)

Only artifacts that pass all quality gates are pushed.

CI Finalize Stage

The finalize stage completes the CI pipeline:

  • Generate pipeline summary reports
  • Send notifications to ChatOps channels (Slack, Teams)
  • Create git tags marking successful builds
  • Trigger downstream CD pipelines

Continuous Deployment

---
config:
  look: handDrawn
  theme: neutral
---
flowchart LR
  init --> diff --> deploy --> regression --> remediation --> finalize

  click init "#cd-init-stage"
  click diff "#cd-diff-stage"
  click deploy "#cd-deploy-stage"
  click regression "#cd-regression-stage"
  click remediation "#cd-remediation-stage"
  click finalize "#cd-finalize-stage"

CD pipelines are triggered by git tags created during CI, ensuring only validated artifacts are deployed.

CD Init Stage

The init stage picks up the artifact corresponding to the git tag:

  • Pull container image from registry
  • Download build artifacts from storage
  • Validate artifact signatures/checksums

CD Diff Stage

Before deployment, a diff shows what will change:

  • Kubernetes - helm diff shows manifest changes
  • Terraform - terraform plan shows infrastructure changes
  • Database - Migration previews show schema changes

This provides visibility and can gate deployments requiring approval.

CD Deploy Stage

The deploy stage applies changes to the target environment:

  • Rolling updates for zero-downtime deployments
  • Blue/green or canary strategies for risk mitigation
  • Database migrations with rollback capabilities

CD Regression Stage

After deployment, regression tests validate the live environment:

  • Smoke tests verify critical paths work
  • API contract tests ensure backwards compatibility
  • Performance tests catch degradation
  • Security scans of running infrastructure

CD Remediation Stage

If regression tests fail, automated remediation kicks in:

  • Rollback - Revert to previous known-good version
  • Alerting - Page on-call engineers
  • Incident creation - Open tickets for tracking

CD Finalize Stage

The finalize stage completes the CD pipeline:

  • Update deployment tracking systems
  • Send success/failure notifications
  • Update dashboards and metrics
  • Close deployment tickets

Principles

  1. Fail Fast - Cheap checks run first; expensive checks run last
  2. Artifact Integrity - Build once, deploy everywhere
  3. Immutable Artifacts - Never modify artifacts after build
  4. Gated Progression - Each stage must pass before the next
  5. Observability - Every stage produces logs, metrics, and traces
  6. Reproducibility - Any build can be recreated from git tag