go

Go Best Practices

Overview

Aspect	Recommendation
Version	Go 1.21+
Modules	Always use go modules
Errors	Return errors, don't panic
Concurrency	Channels and goroutines

---

Project Structure

myproject/
├── cmd/
│   └── myapp/
│       └── main.go          # Application entry point
├── internal/                 # Private application code
│   ├── handlers/
│   ├── services/
│   └── repository/
├── pkg/                      # Public libraries
│   └── utils/
├── api/                      # API definitions (OpenAPI, proto)
├── config/
├── go.mod
├── go.sum
└── Makefile

---

Error Handling

Return Errors, Don't Panic

// ✅ Return errors
func GetUser(id string) (*User, error) {
    user, err := db.Find(id)
    if err != nil {
        return nil, fmt.Errorf("failed to get user %s: %w", id, err)
    }
    return user, nil
}

// ❌ Don't panic for expected errors
func GetUser(id string) *User {
    user, err := db.Find(id)
    if err != nil {
        panic(err)  // Bad!
    }
    return user
}

Custom Error Types

type NotFoundError struct {
    Resource string
    ID       string
}

func (e *NotFoundError) Error() string {
    return fmt.Sprintf("%s with id %s not found", e.Resource, e.ID)
}

// Check error type
func HandleError(err error) {
    var notFound *NotFoundError
    if errors.As(err, &notFound) {
        // Handle not found
    }
}

Error Wrapping

import "fmt"

func ProcessOrder(id string) error {
    order, err := GetOrder(id)
    if err != nil {
        // Wrap with context
        return fmt.Errorf("process order %s: %w", id, err)
    }
    
    if err := ValidateOrder(order); err != nil {
        return fmt.Errorf("validate order: %w", err)
    }
    
    return nil
}

---

Concurrency

Goroutines and Channels

func FetchAll(urls []string) []Result {
    results := make(chan Result, len(urls))
    
    for _, url := range urls {
        go func(u string) {
            data, err := fetch(u)
            results <- Result{URL: u, Data: data, Err: err}
        }(url)
    }
    
    var output []Result
    for range urls {
        output = append(output, <-results)
    }
    
    return output
}