[refactor] 이메일 발송 비동기식으로 전환

src/main/java/dmu/dasom/api/ApiApplication.java

@@ -3,11 +3,12 @@
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
+import org.springframework.scheduling.annotation.EnableAsync;
 
 @EnableJpaAuditing
 @SpringBootApplication
+@EnableAsync
 public class ApiApplication {
-
 	public static void main(String[] args) {
 		SpringApplication.run(ApiApplication.class, args);
 	}

src/main/java/dmu/dasom/api/domain/applicant/service/ApplicantServiceImpl.java

@@ -132,11 +132,7 @@ public void sendEmailsToApplicants(MailType mailType) {
         }
 
         for (Applicant applicant : applicants) {
-            try {
-                emailService.sendEmail(applicant.getEmail(), applicant.getName(), mailType);
-            } catch (MessagingException e) {
-                System.err.println("Failed to send email to: " + applicant.getEmail());
-            }
+            emailService.sendEmail(applicant.getEmail(), applicant.getName(), mailType);
         }
     }
 

src/main/java/dmu/dasom/api/domain/google/entity/EmailLog.java

@@ -0,0 +1,40 @@
+package dmu.dasom.api.domain.google.entity;
+
+import dmu.dasom.api.domain.google.enums.MailSendStatus;
+import jakarta.persistence.*;
+import lombok.*;
+import org.hibernate.annotations.CreationTimestamp;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Getter
+@Builder
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+public class EmailLog {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false)
+    private String recipientEmail;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private MailSendStatus status;
+
+    private String errorMessage;
+
+    @CreationTimestamp
+    private LocalDateTime sentAt;
+
+    public static EmailLog of(String recipientEmail, MailSendStatus status, String errorMessage) {
+        return EmailLog.builder()
+                .recipientEmail(recipientEmail)
+                .status(status)
+                .errorMessage(errorMessage)
+                .build();
+    }
+}

src/main/java/dmu/dasom/api/domain/google/enums/MailSendStatus.java

@@ -0,0 +1,6 @@
+package dmu.dasom.api.domain.google.enums;
+
+public enum MailSendStatus {
+    SUCCESS,
+    FAILURE
+}

src/main/java/dmu/dasom/api/domain/google/enums/MailTemplate.java

@@ -0,0 +1,26 @@
+package dmu.dasom.api.domain.google.enums;
+
+import dmu.dasom.api.domain.common.exception.CustomException;
+import dmu.dasom.api.domain.common.exception.ErrorCode;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import java.util.Arrays;
+
+@Getter
+@RequiredArgsConstructor
+public enum MailTemplate {
+    DOCUMENT_RESULT(MailType.DOCUMENT_RESULT, "동양미래대학교 컴퓨터소프트웨어공학과 전공 동아리 DASOM 서류 결과 안내", "document-result-email"),
+    FINAL_RESULT(MailType.FINAL_RESULT, "동양미래대학교 컴퓨터소프트웨어공학과 전공 동아리 DASOM 최종 면접 결과 안내", "final-result-email");
+
+    private final MailType mailType;
+    private final String subject;
+    private final String templateName;
+
+    public static MailTemplate getMailType(MailType mailType) {
+        return Arrays.stream(values())
+                .filter(template -> template.getMailType() == mailType)
+                .findFirst()
+                .orElseThrow(() -> new CustomException(ErrorCode.MAIL_TYPE_NOT_VALID));
+    }
+}

src/main/java/dmu/dasom/api/domain/google/repository/EmailLogRepository.java

@@ -0,0 +1,7 @@
+package dmu.dasom.api.domain.google.repository;
+
+import dmu.dasom.api.domain.google.entity.EmailLog;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface EmailLogRepository extends JpaRepository<EmailLog, Long> {
+}

src/main/java/dmu/dasom/api/domain/google/service/EmailLogService.java

@@ -0,0 +1,21 @@
+package dmu.dasom.api.domain.google.service;
+
+import dmu.dasom.api.domain.google.entity.EmailLog;
+import dmu.dasom.api.domain.google.enums.MailSendStatus;
+import dmu.dasom.api.domain.google.repository.EmailLogRepository;
+import lombok.RequiredArgsConstructor;
+import org.springframework.scheduling.annotation.Async;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class EmailLogService {
+
+    private final EmailLogRepository emailLogRepository;
+
+    @Async
+    public void logEmailSending(String recipientEmail, MailSendStatus status, String errorMessage) {
+        EmailLog emailLog = EmailLog.of(recipientEmail, status, errorMessage);
+        emailLogRepository.save(emailLog);
+    }
+}

src/main/java/dmu/dasom/api/domain/google/service/EmailService.java

@@ -2,79 +2,78 @@
 
 import dmu.dasom.api.domain.common.exception.CustomException;
 import dmu.dasom.api.domain.common.exception.ErrorCode;
+import dmu.dasom.api.domain.google.enums.MailSendStatus;
+import dmu.dasom.api.domain.google.enums.MailTemplate;
 import dmu.dasom.api.domain.google.enums.MailType;
 import jakarta.mail.MessagingException;
 import jakarta.mail.internet.MimeMessage;
 import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.mail.javamail.JavaMailSender;
 import org.springframework.mail.javamail.MimeMessageHelper;
+import org.springframework.scheduling.annotation.Async;
 import org.springframework.stereotype.Service;
 import org.thymeleaf.TemplateEngine;
 import org.thymeleaf.context.Context;
 
+@Slf4j
 @RequiredArgsConstructor
 @Service
 public class EmailService {
 
     private final TemplateEngine templateEngine;
     private final JavaMailSender javaMailSender;
+    private final EmailLogService emailLogService;
 
     @Value("${spring.mail.username}")
     private String from;
 
-    public void sendEmail(String to, String name, MailType mailType) throws MessagingException {
-        if (mailType == null){
-            throw new CustomException(ErrorCode.MAIL_TYPE_NOT_VALID);
-        }
+    @Async
+    public void sendEmail(String to, String name, MailType mailType) {
+        MailSendStatus mailSendStatus = MailSendStatus.SUCCESS;
+        String errorMessage = null;
+        try {
+            if (mailType == null) {
+                throw new CustomException(ErrorCode.MAIL_TYPE_NOT_VALID);
+            }
 
-        // 메일 제목 및 템플릿 설정
-        String subject;
-        String emailContent;
-        String buttonUrl = "https://dmu-dasom.or.kr/recruit/result";
-        String buttonText;
+            // 메일 템플릿 조회
+            MailTemplate mailTemplate = MailTemplate.getMailType(mailType);
+            String buttonUrl = "https://dmu-dasom.or.kr/recruit/result";
 
-        switch (mailType) {
-            case DOCUMENT_RESULT -> {
-                subject = "동양미래대학교 컴퓨터소프트웨어공학과 전공 동아리 DASOM 서류 결과 안내";
-                emailContent = "먼저 다솜 34기에 많은 관심을 두고 지원해 주셔서 감사드리며,<br>" +
-                        "내부 서류 평가 결과 및 추후 일정에 관해 안내해드리고자 이메일을 발송하게 되었습니다.<br>" +
-                        "서류 전형 결과는 아래 버튼 혹은 홈페이지를 통해 확인이 가능합니다.";
-                buttonText = "서류 결과 확인하기";
-            }
-            case FINAL_RESULT -> {
-                subject = "동양미래대학교 컴퓨터소프트웨어공학과 전공 동아리 DASOM 최종 면접 결과 안내";
-                emailContent = "먼저 다솜 34기에 많은 관심을 두고 지원해 주셔서 감사드리며,<br>" +
-                        "최종 면접 결과 및 추후 일정에 관해 안내해드리고자 이메일을 발송하게 되었습니다.<br>" +
-                        "최종 면접 결과는 아래 버튼 혹은 홈페이지를 통해 확인이 가능합니다.";
-                buttonText = "최종 결과 확인하기";
-            }
-            default -> throw new IllegalStateException("Unexpected value: " + mailType);
-        }
+            // HTML 템플릿에 전달할 데이터 설정
+            Context context = new Context();
+            context.setVariable("name", name); // 지원자 이름 전달
+            context.setVariable("buttonUrl", buttonUrl); // 버튼 링크 전달
 
-        // HTML 템플릿에 전달할 데이터 설정
-        Context context = new Context();
-        context.setVariable("name", name); // 지원자 이름 전달
-        context.setVariable("emailContent", emailContent); // 이메일 내용 전달
-        context.setVariable("buttonUrl", buttonUrl); // 버튼 링크 전달
-        context.setVariable("buttonText", buttonText);
 
-        // HTML 템플릿 처리
-        String htmlBody = templateEngine.process("email-template", context);
+            // HTML 템플릿 처리
+            String htmlBody = templateEngine.process(mailTemplate.getTemplateName(), context);
 
-        // 이메일 생성 및 전송
-        MimeMessage message = javaMailSender.createMimeMessage();
-        MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
+            // 이메일 생성 및 전송
+            MimeMessage message = javaMailSender.createMimeMessage();
+            MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
 
-        helper.setTo(to);
-        helper.setSubject(subject);
-        helper.setText(htmlBody, true);
-        helper.setFrom((from != null && !from.isEmpty()) ? from : "[email protected]");
+            helper.setTo(to);
+            helper.setSubject(mailTemplate.getSubject());
+            helper.setText(htmlBody, true);
+            helper.setFrom((from != null && !from.isEmpty()) ? from : "[email protected]");
 
-        // Content-Type을 명시적으로 설정
-        message.setContent(htmlBody, "text/html; charset=utf-8");
+            // Content-Type을 명시적으로 설정
+            message.setContent(htmlBody, "text/html; charset=utf-8");
 
-        javaMailSender.send(message);
+            javaMailSender.send(message);
+            log.info("Email sent successfull {}", to);
+        } catch (MessagingException e) {
+            log.error("Failed to send email to {}: {}", to, e.getMessage());
+            mailSendStatus = MailSendStatus.FAILURE;
+            errorMessage = e.getMessage();
+        } catch (CustomException e) {
+            log.error("Email sending error for {}: {}", to, e.getMessage());
+            mailSendStatus = MailSendStatus.FAILURE;
+            errorMessage = e.getMessage();
+        }
+        emailLogService.logEmailSending(to, mailSendStatus, errorMessage);
     }
-
 }

src/main/resources/templates/document-result-email.html

@@ -0,0 +1,122 @@
+<!DOCTYPE html>
+<html lang="ko">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta name="color-scheme" content="light dark">
+    <meta name="supported-color-schemes" content="light dark">
+    <title>이메일 안내</title>
+</head>
+<body style="
+            background-color: #17171B;
+            color: white !important;
+            font-family: 'Pretendard', sans-serif;
+            display: flex;
+            justify-content: center;
+            align-items: center;
+            height: 100vh;
+            margin: 0;">
+<div style="
+            width: 740px;
+            height: 680px;
+            background: #17171B;
+            padding: 30px;
+            position: relative;">
+    <div style="
+            display: flex;
+            justify-content: center;
+            position: relative;
+            margin-bottom: 20px;">
+        <div style="
+            width: 100%;
+            display: flex;
+            justify-content: space-between;
+            align-items: center;">
+            <div style="
+                flex: 1;
+                border-top: 1px solid #00B493;
+                margin: 0 10px;">
+
+            </div>
+            <img src="https://dmu-dasom.or.kr/static/media/dasomLogo.c82d220d8093c3cb8d7fc0b148cafcd1.svg" alt="로고" style="
+            width: 21px;
+            height: 24px;
+            border-radius: 3px;">
+            <div style="
+            flex: 1;
+            border-top: 1px solid #00B493;
+            margin: 0 10px;">
+            </div>
+        </div>
+    </div>
+
+    <div style="
+            font-size: 48px;
+            font-weight: 900;
+            color: #00B493;
+            margin-bottom: 30px;">
+        DASOM
+    </div>
+    <div style="
+            font-size: 20px;
+            font-weight: 600;
+            margin-bottom: 5px;
+            color: white !important;"
+            th:text="${name} + '님 안녕하세요.'">
+    </div>
+    <div style="
+            font-size: 20px;
+            font-weight: 600;
+            margin-bottom: 5px;
+            color: white !important;">
+        컴퓨터공학부 전공동아리 다솜입니다.
+    </div>
+
+    <div style="
+            font-size: 16px;
+            font-weight: 400;
+            line-height: 2.5;
+            text-align: right;
+            margin-bottom: 40px;
+            color: white !important;">
+        먼저 다솜 35기에 많은 관심을 두고 지원해 주셔서 감사드리며,<br>
+        내부 서류 평가 결과 및 추후 일정에 관해 안내해드리고자 이메일을 발송하게 되었습니다.<br>
+        서류 전형 결과는 아래 버튼 혹은 홈페이지를 통해 확인이 가능합니다.
+    </div>
+
+    <div style="display: flex;
+            justify-content: flex-end;
+            margin-bottom: 40px;">
+        <a th:href="${buttonUrl}"
+            style="
+            background: #00B493;
+            color: white !important;
+            font-size: 16px;
+            font-weight: 400;
+            padding: 10px 20px;
+            border-radius: 5px;
+            display: flex;
+            align-items: center;
+            text-decoration: none;">
+            <span>서류 결과 확인하기</span>
+            <span style="
+            border: solid white;
+            border-width: 0 2px 2px 0;
+            display: inline-block;
+            padding: 5px;
+            transform: rotate(-45deg);
+            margin-left: 10px;">
+            </span>
+        </a>
+    </div>
+
+    <div style="font-size: 16px;
+            font-weight: 400;
+            line-height: 1.5;
+            color: white !important;">
+        또한, 문의 사항은 본 메일에 회신 또는 아래 번호로 편하게 연락 부탁드립니다.<br>
+        010-6361-3481
+    </div>
+</div>
+</body>
+</html>