CI/CD — Concepts & Goals

Continuous Integration (CI)

Developers integrate code into a shared repository frequently — multiple times per day. Each integration is verified automatically: build, lint, test.

Developer pushes → CI runs → Build + Test → Result in minutes

The goal is not automation for its own sake. The goal is fast feedback. A developer who finds out their change broke the build in 5 minutes fixes it in 5 minutes. A developer who finds out in 2 days has lost all context.

CI Requirements

Requirement	Why
Frequent commits (at least daily)	Small changes = small failures = easy fixes
Automated build	Manual builds don't scale
Automated tests	Human verification is slow and inconsistent
Fast feedback loop	> 15 minutes kills developer flow

Continuous Delivery vs Continuous Deployment

These terms are often confused. They differ in the final step.

Continuous Delivery

The codebase is always in a deployable state. Every commit that passes CI could be released to production. The actual release to production is a manual decision.

Commit → CI → All tests pass → Artifact ready → [Manual gate] → Production

Used when: regulatory requirements, business sign-off needed, controlled release windows.

Continuous Deployment

Every commit that passes CI is automatically deployed to production. No human in the loop between merge and production.

Commit → CI → All tests pass → Auto-deploy → Production

Used when: high-confidence test suite, mature monitoring, fast rollback capability.

The Spectrum

CI only          Continuous Delivery       Continuous Deployment
   │                     │                        │
Automate        Automate + always          Automate + auto-ship
build/test       deployable                  to production

Most organisations operate at Continuous Delivery. Full Continuous Deployment requires very high confidence in automated verification.

Goals

Goal	Concrete Outcome
Fast feedback	Failures found in < 10 minutes
High quality	Broken code never reaches production
Reliable releases	Every release is the same repeatable process
Reduced manual work	No manual build/deploy steps

The Core Feedback Loop

Write code
    ↓
Commit & push
    ↓
CI runs (build → lint → test)
    ↓
Pass → merge/deploy
Fail → developer fixes immediately (context is fresh)

Every extra minute in this loop multiplies the cost of fixing the problem. A 30-second build + 5-minute test suite is a competitive advantage.