Package Development (Core/Libs)

🎯 Core Principles

All code in pkg/ must strictly adhere to:

1. •

   SOLID:

   • •SRP: Each function/struct does ONE thing well.
   • •OCP: Open for extension, closed for modification (use Interfaces).
   • •LSP: Subtypes must be substitutable for base types.
   • •ISP: Small, specific interfaces are better than large, general ones.
   • •DIP: Depend on abstractions, not concretions.
2. •

   KISS (Keep It Simple, Stupid):

   • •Avoid over-engineering.
   • •Simple code is easier to debug and maintain.
3. •

   DRY (Don't Repeat Yourself):

   • •Abstract common logic into reusable functions.
   • •Single source of truth.

🏗️ OOP in Go

Use Go's idiomatic OOP features to ensure extensibility and clean code:

• •

  Encapsulation:

  • •Use private structs/fields (lowerCase) for internal implementation.
  • •Expose only what is necessary via public methods (PascalCase).
  • •Use New... constructors to enforce initialization logic.
• •

  Composition over Inheritance:

  • •Embed structs to reuse behavior.
  • •Use Interfaces to define behavior contracts.
• •

  Polymorphism:

  • •Accept Interfaces as function arguments, return Interfaces (or concrete types if strict).

📝 Coding Standards

• •Naming: Clear, descriptive names. pkg functions are used everywhere, so ambiguity is expensive.
• •Documentation: EVERY exported function/type MUST have a comment explaining what it does and why.
• •Coverage: Target >90% test coverage for pkg. Bugs here propagate everywhere.
• •Stability: Avoid breaking changes. Deprecate old methods before removing them.

Example

// ✅ GOOD: Defined Interface (DIP)
type Logger interface {
    Info(msg string)
    Error(msg string, err error)
}

// ✅ GOOD: Encapsulation & Composition
type FileLogger struct {
    filterLevel string // Private
    writer      io.Writer
}

// Constructor
func NewFileLogger(w io.Writer) Logger {
    return &FileLogger{
        filterLevel: "INFO",
        writer:      w,
    }
}

// Implementation
func (l *FileLogger) Info(msg string) {
    // ... implementation
}