벌크헤드 패턴

Java code

import java.util.concurrent.*;

public class BulkheadPattern {
    // 스레드 풀 기반 벌크헤드
    static class Bulkhead {
        private final String name;
        private final Semaphore semaphore;
        private final ExecutorService executor;

        Bulkhead(String name, int maxConcurrent) {
            this.name = name;
            this.semaphore = new Semaphore(maxConcurrent);
            this.executor = Executors.newFixedThreadPool(maxConcurrent);
        }

        <T> CompletableFuture<T> execute(Callable<T> task) {
            return CompletableFuture.supplyAsync(() -> {
                try {
                    if (!semaphore.tryAcquire(1, TimeUnit.SECONDS)) {
                        throw new RuntimeException(name + " 벌크헤드 포화");
                    }
                    try {
                        return task.call();
                    } finally {
                        semaphore.release();
                    }
                } catch (Exception e) {
                    throw new CompletionException(e);
                }
            }, executor);
        }

        void shutdown() { executor.shutdown(); }
    }

    public static void main(String[] args) throws Exception {
        // 서비스별 격리된 벌크헤드
        Bulkhead orderBulkhead = new Bulkhead("주문", 3);
        Bulkhead paymentBulkhead = new Bulkhead("결제", 2);

        // 주문 서비스 장애가 결제에 영향 안 줌
        var orderResult = orderBulkhead.execute(() -> {
            Thread.sleep(100);
            return "주문 처리 완료";
        });

        var payResult = paymentBulkhead.execute(() -> {
            Thread.sleep(50);
            return "결제 처리 완료";
        });

        System.out.println(orderResult.get());
        System.out.println(payResult.get());

        orderBulkhead.shutdown();
        paymentBulkhead.shutdown();
    }
}