go

Go Development

Purpose: Best practices for Go development including project structure, concurrency, error handling, and testing.

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When to Use This Skill

• Building Go applications and microservices
• Implementing error handling with wrapping and sentinel errors
• Writing concurrent code with goroutines and channels
• Designing Go interfaces for testability
• Structuring Go project layouts

Decision Tree

Go Project Decision
+-- Building a CLI tool?
|   +-- Simple? -> Single cmd/main.go
|   +-- Multi-command? -> cobra or urfave/cli
+-- Building a web service?
|   +-- Standard library sufficient? -> net/http + http.ServeMux
|   +-- Need middleware/routing? -> chi, gorilla/mux, or gin
+-- Need concurrency?
|   +-- Fan-out/fan-in? -> Goroutines + channels
|   +-- Shared state? -> sync.Mutex or sync.RWMutex
|   +-- Cancellation? -> context.Context
+-- Data access?
|   +-- SQL database? -> database/sql + sqlx
|   +-- ORM preferred? -> GORM (with caution)
+-- Reusable library? -> pkg/ directory, keep interfaces small

Prerequisites

• Go 1.26+ installed
• Go modules enabled

Table of Contents

1. Project Structure
2. Code Style
3. Error Handling
4. Concurrency
5. Testing
6. Interfaces
7. Performance
8. Security
9. Best Practices

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Project Structure

Standard Layout

project/
+-- cmd/
| -- myapp/
| -- main.go # Application entry point
+-- internal/
| +-- config/ # Configuration handling
| +-- handlers/ # HTTP handlers
| +-- models/ # Domain models
| +-- repository/ # Data access
| -- service/ # Business logic
+-- pkg/
| -- utils/ # Reusable packages
+-- api/
| -- openapi.yaml # API specification
+-- configs/
| -- config.yaml # Configuration files
+-- scripts/
| -- setup.sh # Build/deploy scripts
+-- go.mod
+-- go.sum
-- README.md

Package Naming

// Package names should be lowercase, short, and descriptive
package user // Good
package userService // Bad - no camelCase
package user_svc // Bad - no underscores

// Import path should match directory structure
import "myapp/internal/service"