feat: 투표와 댓글 추가 시 낙관적 락 사용한다

src/main/java/life/offonoff/ab/application/service/CommentService.java

@@ -18,14 +18,17 @@
 import life.offonoff.ab.web.response.CommentReactionResponse;
 import life.offonoff.ab.web.response.CommentResponse;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
 import static life.offonoff.ab.application.service.common.LengthInfo.COMMENT_CONTENT;
 
+@Slf4j
 @RequiredArgsConstructor
 @Transactional(readOnly = true)
 @Service
@@ -92,9 +95,16 @@ private Vote findVote(Long memberId, Long topicId) {
     //== save ==//
     @Transactional
     public CommentResponse register(Long memberId, CommentRequest request) {
-
         Comment comment = createComment(memberId, request);
 
+        try {
+            // 토픽의 댓글수 먼저 업데이트
+            topicRepository.flush();
+        } catch (ObjectOptimisticLockingFailureException e) {
+            log.warn(e.getMessage());
+            throw new CommentConcurrencyException();
+        }
+
         commentRepository.save(comment);
 
         eventPublisher.publishEvent(new CommentedEvent(comment));

src/main/java/life/offonoff/ab/application/service/TopicService.java

@@ -27,6 +27,7 @@
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -199,6 +200,15 @@ private VoteResponse voteForTopic(final Member member, final Topic topic, final
 
         Vote vote = new Vote(choiceOption, votedAt);
         vote.associate(member, topic);
+
+        try {
+            // 토픽의 투표수 먼저 업데이트
+            topicRepository.flush();
+        } catch (ObjectOptimisticLockingFailureException e) {
+            log.warn(e.getMessage());
+            throw new VoteConcurrencyException();
+        }
+
         voteRepository.save(vote);
 
         // publish VotedEvent

src/main/java/life/offonoff/ab/domain/topic/Topic.java

@@ -60,6 +60,9 @@ public class Topic extends BaseEntity {
     @Enumerated(EnumType.STRING)
     private TopicStatus status = TopicStatus.VOTING;
 
+    @Version
+    private Integer version;
+
     private int commentCount = 0;
     private int voteCount = 0;
     private int hideCount = 0;

src/main/java/life/offonoff/ab/domain/topic/choice/Choice.java

@@ -28,6 +28,9 @@ public class Choice extends BaseEntity {
     @JoinColumn(name = "choice_content_id")
     private ChoiceContent content;
 
+    @Version
+    private Integer version;
+
     private int voteCount;
 
     //== Constructor ==//

src/main/java/life/offonoff/ab/exception/AbCode.java

@@ -63,5 +63,10 @@ public enum AbCode {
 
     NOT_KOREAN_ENGLISH_NUMBER,
 
-    S3_INVALID_FILE_URL, S3_INVALID_KEY_NAME, DEACTIVATED_MEMBER;
+    S3_INVALID_FILE_URL,
+    S3_INVALID_KEY_NAME,
+    DEACTIVATED_MEMBER,
+
+    CONCURRENCY_VIOLATION,
+    ;
 }

src/main/java/life/offonoff/ab/exception/CommentConcurrencyException.java

@@ -0,0 +1,9 @@
+package life.offonoff.ab.exception;
+
+public class CommentConcurrencyException extends ConcurrencyViolationException {
+    private static final String HINT = "토픽의 댓글수 업데이트 중 낙관적 락 실패";
+    @Override
+    public String getHint() {
+        return HINT;
+    }
+}

src/main/java/life/offonoff/ab/exception/ConcurrencyViolationException.java

@@ -0,0 +1,22 @@
+package life.offonoff.ab.exception;
+
+import org.springframework.http.HttpStatus;
+
+public abstract class ConcurrencyViolationException extends AbException{
+    private static final AbCode AB_CODE = AbCode.CONCURRENCY_VIOLATION;
+    private static final String MESSAGE = "서버 문제가 발생했습니다. 다시 시도해주세요.";
+
+    public ConcurrencyViolationException() {
+        super(MESSAGE);
+    }
+
+    @Override
+    public int getHttpStatusCode() {
+        return HttpStatus.CONFLICT.value();
+    }
+
+    @Override
+    public AbCode getAbCode() {
+        return AB_CODE;
+    }
+}

src/main/java/life/offonoff/ab/exception/VoteConcurrencyException.java

@@ -0,0 +1,10 @@
+package life.offonoff.ab.exception;
+
+public class VoteConcurrencyException extends ConcurrencyViolationException {
+    private static final String HINT = "투표 시 동시성 문제 발생";
+
+    @Override
+    public String getHint() {
+        return HINT;
+    }
+}

src/main/java/life/offonoff/ab/web/common/GlobalExceptionHandler.java

@@ -5,15 +5,15 @@
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.HttpMessageNotReadableException;
+import org.springframework.orm.ObjectOptimisticLockingFailureException;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
 import org.springframework.web.method.annotation.MethodArgumentTypeMismatchException;
 
 import java.util.stream.Collectors;
 
-import static life.offonoff.ab.exception.AbCode.INTERNAL_SERVER_ERROR;
-import static life.offonoff.ab.exception.AbCode.INVALID_FIELD;
+import static life.offonoff.ab.exception.AbCode.*;
 
 @Slf4j
 // 예외가 발생했을 때 json 형태로 반환할 때 사용하는 어노테이션
@@ -74,6 +74,20 @@ private ResponseEntity<ErrorWrapper> handleHttpMessageNotReadableException(final
         return handleException(e);
     }
 
+    @ExceptionHandler(ObjectOptimisticLockingFailureException.class)
+    private ResponseEntity<ErrorWrapper> handleOptimisticLockingFailureException(
+            final ObjectOptimisticLockingFailureException e) {
+        log.warn("Unhandled Optimistic Lock! = ", e);
+        final String message = "서버 문제가 발생했습니다. 다시 시도해주세요.";
+        final ErrorWrapper errorWrapper = new ErrorWrapper(
+                CONCURRENCY_VIOLATION,
+                ErrorContent.of(message, HttpStatus.CONFLICT.value())
+        );
+        return ResponseEntity
+                .status(HttpStatus.CONFLICT)
+                .body(errorWrapper);
+    }
+
     @ExceptionHandler(Exception.class)
     private ResponseEntity<ErrorWrapper> handleException(final Exception exception) {
         log.warn("! Unfiltered Exception = ", exception);

src/test/java/life/offonoff/ab/application/service/TopicServiceConcurrencyTest.java

@@ -10,6 +10,7 @@
 import life.offonoff.ab.domain.topic.TopicSide;
 import life.offonoff.ab.domain.topic.choice.Choice;
 import life.offonoff.ab.domain.topic.choice.ChoiceOption;
+import life.offonoff.ab.exception.VoteConcurrencyException;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -20,6 +21,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.IntStream;
 
 import static life.offonoff.ab.domain.TestEntityUtil.createRandomMember;
@@ -76,10 +78,15 @@ void voteForTopicByMember() throws InterruptedException {
         // when
         long votedAt = System.currentTimeMillis() / 1000;
         final CountDownLatch latch = new CountDownLatch(COUNT);
+        AtomicInteger failureCounter = new AtomicInteger(0);
         voters.forEach(voter -> {
             executorService.execute(() -> {
-                topicService.voteForTopicByMember(
-                        topic.getId(), voter.getId(), new VoteRequest(ChoiceOption.CHOICE_A, votedAt));
+                try {
+                    topicService.voteForTopicByMember(
+                            topic.getId(), voter.getId(), new VoteRequest(ChoiceOption.CHOICE_A, votedAt));
+                } catch (VoteConcurrencyException e) {
+                    failureCounter.incrementAndGet();
+                }
                 latch.countDown();
             });
         });
@@ -89,8 +96,9 @@ void voteForTopicByMember() throws InterruptedException {
         Topic updatedTopic = em.find(Topic.class, topic.getId());
         Choice votedChoice = updatedTopic.getChoices().stream().filter(c -> c.getChoiceOption().equals(ChoiceOption.CHOICE_A)).findAny().get();
         // 투표수는 COUNT와 동일해야함
-        assertThat(updatedTopic.getVoteCount()).isEqualTo(COUNT);
-        assertThat(votedChoice.getVoteCount()).isEqualTo(COUNT);
+        int successfulVoteCount = COUNT - failureCounter.get();
+        assertThat(updatedTopic.getVoteCount()).isEqualTo(successfulVoteCount);
+        assertThat(votedChoice.getVoteCount()).isEqualTo(successfulVoteCount);
     }
 
 }