Discord Webhook 알림 연동 (#161)

src/main/java/com/ryu/studyhelper/auth/GoogleOAuth2UserService.java

@@ -2,6 +2,8 @@
 
 import com.ryu.studyhelper.auth.dto.OAuthInfo;
 import com.ryu.studyhelper.config.security.PrincipalDetails;
+import com.ryu.studyhelper.infrastructure.discord.DiscordMessage;
+import com.ryu.studyhelper.infrastructure.discord.DiscordNotifier;
 import com.ryu.studyhelper.member.repository.MemberRepository;
 import com.ryu.studyhelper.member.domain.Member;
 import jakarta.transaction.Transactional;
@@ -22,6 +24,7 @@
 public class GoogleOAuth2UserService extends DefaultOAuth2UserService {
 
     private final MemberRepository memberRepository;
+    private final DiscordNotifier discordNotifier;
 
     @Override
     public OAuth2User loadUser(OAuth2UserRequest userRequest) throws OAuth2AuthenticationException {
@@ -54,7 +57,25 @@ private Member saveOrUpdateMember(OAuthInfo oAuthInfo) {
             Member newMember = Member.create("google", oAuthInfo.getProviderId(), oAuthInfo.getEmail());
             Member savedMember = memberRepository.save(newMember);
             log.info("신규 사용자 생성 완료: {}", savedMember.getEmail());
+
+            try {
+                discordNotifier.sendEvent(DiscordMessage.event("신규 회원 가입",
+                        "회원 ID", String.valueOf(savedMember.getId()),
+                        "이메일", maskEmail(savedMember.getEmail())
+                ));
+            } catch (Exception e) {
+                log.warn("Discord 알림 전송 실패", e);
+            }
+
             return savedMember;
         }
     }
+
+    private String maskEmail(String email) {
+        int atIndex = email.indexOf('@');
+        if (atIndex <= 3) {
+            return email.charAt(0) + "***" + email.substring(atIndex);
+        }
+        return email.substring(0, 3) + "***" + email.substring(atIndex);
+    }
 }

src/main/java/com/ryu/studyhelper/infrastructure/discord/DiscordMessage.java

@@ -0,0 +1,67 @@
+package com.ryu.studyhelper.infrastructure.discord;
+
+import java.time.Instant;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Discord Embed 메시지 구조
+ *
+ * 사용법: 용도에 맞는 팩토리 메서드를 사용
+ * - batchResult() : 배치 작업 결과 (스케줄러)
+ * - error()       : 예외 발생 (스케줄러 실패)
+ * - event()       : 비즈니스 이벤트 (가입, 핸들등록 등)
+ */
+public record DiscordMessage(List<Embed> embeds) {
+
+    record Embed(String title, String description, int color, List<Field> fields, String timestamp) {}
+
+    record Field(String name, String value, boolean inline) {}
+
+    private static final int COLOR_SUCCESS = 0x2ECC71;
+    private static final int COLOR_ERROR = 0xE74C3C;
+    private static final int COLOR_INFO = 0x3498DB;
+
+    /**
+     * 배치 작업 결과
+     * 실패가 있으면 빨간색, 없으면 초록색
+     */
+    public static DiscordMessage batchResult(String title, int totalCount, int successCount, int failCount, long elapsedMs) {
+        int color = failCount > 0 ? COLOR_ERROR : COLOR_SUCCESS;
+        return create(title, color, List.of(
+                new Field("대상", totalCount + "건", true),
+                new Field("성공", successCount + "건", true),
+                new Field("실패", failCount + "건", true),
+                new Field("소요시간", elapsedMs + "ms", true)
+        ));
+    }
+
+    /**
+     * 예외 발생 (빨간색)
+     */
+    public static DiscordMessage error(String title, Exception e, long elapsedMs) {
+        return create(title, COLOR_ERROR, List.of(
+                new Field("예외", e.getClass().getSimpleName(), true),
+                new Field("메시지", e.getMessage() != null ? e.getMessage() : "(없음)", false),
+                new Field("소요시간", elapsedMs + "ms", true)
+        ));
+    }
+
+    /**
+     * 비즈니스 이벤트 (파란색)
+     * keyValues는 이름-값 쌍: "회원 ID", "1", "이메일", "test@..."
+     */
+    public static DiscordMessage event(String title, String... keyValues) {
+        List<Field> fields = new ArrayList<>();
+        for (int i = 0; i + 1 < keyValues.length; i += 2) {
+            fields.add(new Field(keyValues[i], keyValues[i + 1], true));
+        }
+        return create(title, COLOR_INFO, fields);
+    }
+
+    private static DiscordMessage create(String title, int color, List<Field> fields) {
+        return new DiscordMessage(List.of(
+                new Embed(title, null, color, fields, Instant.now().toString())
+        ));
+    }
+}

src/main/java/com/ryu/studyhelper/infrastructure/discord/DiscordNotifier.java

@@ -0,0 +1,12 @@
+package com.ryu.studyhelper.infrastructure.discord;
+
+/**
+ * Discord Webhook 알림 인터페이스
+ * 채널별로 분리된 메서드 제공 (스케줄러, 이벤트)
+ */
+public interface DiscordNotifier {
+
+    void sendScheduler(DiscordMessage message);
+
+    void sendEvent(DiscordMessage message);
+}

src/main/java/com/ryu/studyhelper/infrastructure/discord/DiscordProperties.java

@@ -0,0 +1,13 @@
+package com.ryu.studyhelper.infrastructure.discord;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * Discord Webhook URL 설정
+ * 채널별 Webhook URL 바인딩
+ */
+@ConfigurationProperties(prefix = "discord.webhooks")
+public record DiscordProperties(
+        String scheduler,
+        String event
+) {}

src/main/java/com/ryu/studyhelper/infrastructure/discord/DiscordWebhookNotifier.java

@@ -0,0 +1,61 @@
+package com.ryu.studyhelper.infrastructure.discord;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Profile;
+import org.springframework.http.client.SimpleClientHttpRequestFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+import java.time.Duration;
+
+/**
+ * Discord Webhook 알림 구현체 (prod 전용)
+ * RestClient로 Webhook POST 요청
+ */
+@Component
+@Profile("prod")
+@EnableConfigurationProperties(DiscordProperties.class)
+@Slf4j
+public class DiscordWebhookNotifier implements DiscordNotifier {
+
+    private final DiscordProperties properties;
+    private final RestClient restClient;
+
+    public DiscordWebhookNotifier(DiscordProperties properties) {
+        this.properties = properties;
+        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
+        factory.setConnectTimeout(Duration.ofSeconds(3));
+        factory.setReadTimeout(Duration.ofSeconds(5));
+        this.restClient = RestClient.builder()
+                .requestFactory(factory)
+                .build();
+    }
+
+    @Override
+    public void sendScheduler(DiscordMessage message) {
+        send(properties.scheduler(), message);
+    }
+
+    @Override
+    public void sendEvent(DiscordMessage message) {
+        send(properties.event(), message);
+    }
+
+    private void send(String webhookUrl, DiscordMessage message) {
+        if (webhookUrl == null || webhookUrl.isBlank()) {
+            log.debug("Discord webhook URL이 설정되지 않아 알림을 건너뜁니다");
+            return;
+        }
+        try {
+            restClient.post()
+                    .uri(webhookUrl)
+                    .header("Content-Type", "application/json")
+                    .body(message)
+                    .retrieve()
+                    .toBodilessEntity();
+        } catch (Exception e) {
+            log.warn("Discord 알림 전송 실패: {}", e.getMessage());
+        }
+    }
+}

src/main/java/com/ryu/studyhelper/infrastructure/discord/FakeDiscordNotifier.java

@@ -0,0 +1,32 @@
+package com.ryu.studyhelper.infrastructure.discord;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.context.annotation.Profile;
+import org.springframework.stereotype.Component;
+
+/**
+ * 로컬/테스트용 Discord 알림 구현체
+ * 실제 Webhook 호출 대신 로그 출력
+ */
+@Component
+@Profile("!prod")
+@Slf4j
+public class FakeDiscordNotifier implements DiscordNotifier {
+
+    @Override
+    public void sendScheduler(DiscordMessage message) {
+        log.info("[FAKE DISCORD] 스케줄러 알림: {}", extractTitle(message));
+    }
+
+    @Override
+    public void sendEvent(DiscordMessage message) {
+        log.info("[FAKE DISCORD] 이벤트 알림: {}", extractTitle(message));
+    }
+
+    private String extractTitle(DiscordMessage message) {
+        if (message.embeds() == null || message.embeds().isEmpty()) {
+            return "(제목 없음)";
+        }
+        return message.embeds().get(0).title();
+    }
+}

src/main/java/com/ryu/studyhelper/member/MemberService.java

@@ -3,6 +3,8 @@
 import com.ryu.studyhelper.common.enums.CustomResponseStatus;
 import com.ryu.studyhelper.common.exception.CustomException;
 import com.ryu.studyhelper.config.security.jwt.JwtUtil;
+import com.ryu.studyhelper.infrastructure.discord.DiscordMessage;
+import com.ryu.studyhelper.infrastructure.discord.DiscordNotifier;
 import com.ryu.studyhelper.infrastructure.solvedac.SolvedAcClient;
 import com.ryu.studyhelper.infrastructure.mail.sender.MailSender;
 import com.ryu.studyhelper.member.mail.EmailChangeMailBuilder;
@@ -35,6 +37,7 @@ public class MemberService {
     private final JwtUtil jwtUtil;
     private final MailSender mailSender;
     private final EmailChangeMailBuilder emailChangeMailBuilder;
+    private final DiscordNotifier discordNotifier;
     private final Clock clock;
 
     @Value("${FRONTEND_URL:http://localhost:5173}")
@@ -80,6 +83,15 @@ public Member verifySolvedAcHandle(Long memberId, String handle) {
         Member member = getById(memberId);
         member.changeHandle(handle);
 
+        try {
+            discordNotifier.sendEvent(DiscordMessage.event("핸들 등록",
+                    "회원 ID", String.valueOf(memberId),
+                    "핸들", handle
+            ));
+        } catch (Exception e) {
+            log.warn("Discord 알림 전송 실패", e);
+        }
+
         return member;
     }
 

src/main/java/com/ryu/studyhelper/recommendation/dto/internal/BatchResult.java

@@ -0,0 +1,6 @@
+package com.ryu.studyhelper.recommendation.dto.internal;
+
+/**
+ * 배치 작업 결과
+ */
+public record BatchResult(int totalCount, int successCount, int failCount) {}

src/main/java/com/ryu/studyhelper/recommendation/scheduler/EmailSendScheduler.java

@@ -1,5 +1,8 @@
 package com.ryu.studyhelper.recommendation.scheduler;
 
+import com.ryu.studyhelper.infrastructure.discord.DiscordMessage;
+import com.ryu.studyhelper.infrastructure.discord.DiscordNotifier;
+import com.ryu.studyhelper.recommendation.dto.internal.BatchResult;
 import com.ryu.studyhelper.recommendation.service.RecommendationEmailService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -16,26 +19,38 @@
 public class EmailSendScheduler {
 
     private final RecommendationEmailService recommendationEmailService;
+    private final DiscordNotifier discordNotifier;
 
-    /**
-     * 매일 오전 9시에 이메일 발송
-     * Cron 표현식: "0 0 9 * * *" = 매일 9시 0분 0초
-     */
     @Scheduled(cron = "0 0 9 * * *", zone = "Asia/Seoul")
     public void sendPendingEmails() {
         log.info("=== 이메일 발송 배치 작업 시작 ===");
 
         long startTime = System.currentTimeMillis();
+        BatchResult result = null;
+        Exception failure = null;
 
         try {
-            recommendationEmailService.sendAll();
+            result = recommendationEmailService.sendAll();
+            log.info("=== 이메일 발송 배치 작업 완료 === (소요시간: {}ms)", System.currentTimeMillis() - startTime);
+        } catch (Exception e) {
+            failure = e;
+            log.error("=== 이메일 발송 배치 작업 실패 === (소요시간: {}ms)", System.currentTimeMillis() - startTime, e);
+        }
 
-            long endTime = System.currentTimeMillis();
-            log.info("=== 이메일 발송 배치 작업 완료 === (소요시간: {}ms)", endTime - startTime);
+        notifyDiscord(result, failure, System.currentTimeMillis() - startTime);
+    }
 
+    private void notifyDiscord(BatchResult result, Exception failure, long elapsed) {
+        try {
+            if (failure != null) {
+                discordNotifier.sendScheduler(DiscordMessage.error("이메일 발송 배치 실패", failure, elapsed));
+            } else {
+                String title = result.failCount() > 0 ? "이메일 발송 배치 실패" : "이메일 발송 배치 완료";
+                discordNotifier.sendScheduler(DiscordMessage.batchResult(
+                        title, result.totalCount(), result.successCount(), result.failCount(), elapsed));
+            }
         } catch (Exception e) {
-            long endTime = System.currentTimeMillis();
-            log.error("=== 이메일 발송 배치 작업 실패 === (소요시간: {}ms)", endTime - startTime, e);
+            log.warn("Discord 알림 전송 실패", e);
         }
     }
 }

src/main/java/com/ryu/studyhelper/recommendation/scheduler/ProblemRecommendationScheduler.java

@@ -1,5 +1,8 @@
 package com.ryu.studyhelper.recommendation.scheduler;
 
+import com.ryu.studyhelper.infrastructure.discord.DiscordMessage;
+import com.ryu.studyhelper.infrastructure.discord.DiscordNotifier;
+import com.ryu.studyhelper.recommendation.dto.internal.BatchResult;
 import com.ryu.studyhelper.recommendation.service.ScheduledRecommendationService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -16,26 +19,38 @@
 public class ProblemRecommendationScheduler {
 
     private final ScheduledRecommendationService scheduledRecommendationService;
+    private final DiscordNotifier discordNotifier;
 
-    /**
-     * 매일 오전 6시에 문제 추천 준비
-     * Cron 표현식: "0 0 6 * * *" = 매일 6시 0분 0초
-     */
     @Scheduled(cron = "0 0 6 * * *", zone = "Asia/Seoul")
     public void prepareDailyRecommendations() {
         log.info("=== 문제 추천 배치 작업 시작 ===");
 
         long startTime = System.currentTimeMillis();
+        BatchResult result = null;
+        Exception failure = null;
 
         try {
-            scheduledRecommendationService.prepareDailyRecommendations();
+            result = scheduledRecommendationService.prepareDailyRecommendations();
+            log.info("=== 문제 추천 배치 작업 완료 === (소요시간: {}ms)", System.currentTimeMillis() - startTime);
+        } catch (Exception e) {
+            failure = e;
+            log.error("=== 문제 추천 배치 작업 실패 === (소요시간: {}ms)", System.currentTimeMillis() - startTime, e);
+        }
 
-            long endTime = System.currentTimeMillis();
-            log.info("=== 문제 추천 배치 작업 완료 === (소요시간: {}ms)", endTime - startTime);
+        notifyDiscord(result, failure, System.currentTimeMillis() - startTime);
+    }
 
+    private void notifyDiscord(BatchResult result, Exception failure, long elapsed) {
+        try {
+            if (failure != null) {
+                discordNotifier.sendScheduler(DiscordMessage.error("문제 추천 배치 실패", failure, elapsed));
+            } else {
+                String title = result.failCount() > 0 ? "문제 추천 배치 실패" : "문제 추천 배치 완료";
+                discordNotifier.sendScheduler(DiscordMessage.batchResult(
+                        title, result.totalCount(), result.successCount(), result.failCount(), elapsed));
+            }
         } catch (Exception e) {
-            long endTime = System.currentTimeMillis();
-            log.error("=== 문제 추천 배치 작업 실패 === (소요시간: {}ms)", endTime - startTime, e);
+            log.warn("Discord 알림 전송 실패", e);
         }
     }
 }