Package Design & Internal Rules

Structuring maintainable packages, public vs private APIs, and the internal package guard.

Real-World Analogy (Mental Model)

“A restaurant: the dining room is public (`pkg/`), but the food preparation kitchen and pantry are strictly employees-only (`internal/`).”

Key Concepts & Rules To Remember

`internal/` directories are strictly enforced by the Go compiler — cannot be imported by external projects.
Keep packages focused on single responsibilities (e.g. `auth`, `storage`).
Avoid circular package import cycles.

Step-by-Step Code

1. Understanding Package Design & Internal Rules

Structuring maintainable packages, public vs private APIs, and the internal package guard. In Go, package design & internal rules is designed around clarity and high runtime efficiency.

example.goGo 1.24+

myproject/
├── cmd/api/main.go
├── internal/auth/service.go  <-- Private to myproject
└── pkg/validator/check.go    <-- Reusable by others

Common Beginner Pitfalls & Mistakes

Mistake: Misusing package design & internal rules without understanding its memory or concurrency semantics.

✅ Correct Way: Always follow standard Go idioms and verify with tests.

Self Assessment

Knowledge Check

Verify your understanding with these interactive practice questions.

Quizzes

Quick checks for understanding

Multiple-choice with inline explanations—expand to see why.

What is the primary concept behind Package Design & Internal Rules?

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