타임아웃 패턴

Go code

package main

import (
	"context"
	"fmt"
	"time"
)

// 채널 기반 타임아웃
func fetchWithTimeout(timeout time.Duration) (string, error) {
	ch := make(chan string, 1)

	go func() {
		time.Sleep(2 * time.Second) // 느린 작업 시뮬레이션
		ch <- "데이터"
	}()

	select {
	case result := <-ch:
		return result, nil
	case <-time.After(timeout):
		return "", fmt.Errorf("타임아웃: %v", timeout)
	}
}

// context 기반 타임아웃
func fetchWithContext(ctx context.Context) (string, error) {
	ch := make(chan string, 1)
	go func() {
		time.Sleep(500 * time.Millisecond)
		ch <- "빠른 응답"
	}()

	select {
	case result := <-ch:
		return result, nil
	case <-ctx.Done():
		return "", ctx.Err()
	}
}

func main() {
	// 1초 타임아웃 (2초 작업 → 타임아웃)
	_, err := fetchWithTimeout(1 * time.Second)
	fmt.Println(err) // 타임아웃

	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()
	result, _ := fetchWithContext(ctx)
	fmt.Println(result) // 빠른 응답
}