[REFACTOR/90] 다시 로컬 로그와 S3 로그 병합 후 S3 업로드 기능 추가 & Logback 재설정 로직 재설정

src/main/java/LuckyVicky/backend/global/lifecycle/InstanceShutdownHandler.java

@@ -17,5 +17,6 @@ public class InstanceShutdownHandler {
     public void onShutdown() {
         log.info("Application is shutting down. Uploading today's log to S3...");
         logService.uploadDailyLog("today");
+        log.info("Uploaded Log to S3 with PreDestroy");
     }
 }

src/main/java/LuckyVicky/backend/global/s3/S3LogService.java

@@ -1,13 +1,27 @@
 package LuckyVicky.backend.global.s3;
 
+import static LuckyVicky.backend.global.util.Constant.LOG_DATE_FORMAT;
+import static LuckyVicky.backend.global.util.Constant.LOG_LOGBACK_ERROR_FILE_NAME;
+import static LuckyVicky.backend.global.util.Constant.LOG_LOGBACK_FILE_DIRECTORY;
+
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.joran.JoranConfigurator;
+import ch.qos.logback.core.joran.spi.JoranException;
 import com.amazonaws.services.s3.AmazonS3;
+import com.amazonaws.services.s3.model.GetObjectRequest;
 import com.amazonaws.services.s3.model.PutObjectRequest;
+import com.amazonaws.services.s3.model.S3Object;
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.nio.file.Files;
 import java.time.LocalDate;
-import java.time.format.DateTimeFormatter;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.core.env.Environment;
 import org.springframework.stereotype.Service;
@@ -24,50 +38,96 @@ public class S3LogService {
     private String bucket;
 
     public void uploadDailyLog(String day) {
-        File targetFile = getLocalLogFile(day);
-
-        if (!targetFile.exists()) {
+        File localFile = getLocalLogFile(day);
+        if (!localFile.exists()) {
             log.warn("No local log file found for day={}", day);
             return;
         }
 
         String s3Key = buildS3Key(day);
+        File tempFile = new File("temp-" + localFile.getName());
 
         try {
-            // S3에 업로드
-            amazonS3.putObject(new PutObjectRequest(bucket, s3Key, targetFile));
-            log.info("Uploaded log to S3: {} -> s3://{}/{}", targetFile.getName(), bucket, s3Key);
+            // S3에 기존 로그 파일이 있는 경우 다운로드하여 병합
+            if (amazonS3.doesObjectExist(bucket, s3Key)) {
+                log.info("Existing log found in S3. Merging logs...");
+                mergeLogsFromS3(localFile, tempFile, s3Key);
+            } else {
+                Files.copy(localFile.toPath(), tempFile.toPath());
+            }
 
-            // 업로드 후 로컬 파일 삭제
-            Files.deleteIfExists(targetFile.toPath());
+            // 병합된 로그 파일을 S3에 업로드
+            amazonS3.putObject(new PutObjectRequest(bucket, s3Key, tempFile));
+            log.info("Uploaded merged log to S3: {} -> s3://{}/{}", tempFile.getName(), bucket, s3Key);
+
+            // 업로드 후 로컬 로그 파일 삭제 및 Logback 초기화
+            Files.deleteIfExists(localFile.toPath());
+            log.info("Deleted local log file: {}", localFile.getName());
+            resetLogbackContext();
 
         } catch (Exception e) {
-            log.error("Failed to upload log file to S3. day={}, file={}, key={}", day, targetFile, s3Key, e);
+            log.error("Failed to upload or merge log file to S3. day={}, file={}, key={}", day, localFile, s3Key, e);
+        } finally {
+            tempFile.delete(); // 임시 파일 삭제
+        }
+    }
+
+    private void resetLogbackContext() {
+        LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
+        loggerContext.stop(); // 기존 컨텍스트 정지
+
+        try {
+            loggerContext.reset(); // 컨텍스트 초기화
+            JoranConfigurator configurator = new JoranConfigurator();
+            configurator.setContext(loggerContext);
+            configurator.doConfigure(LOG_LOGBACK_FILE_DIRECTORY + LOG_LOGBACK_ERROR_FILE_NAME);
+            loggerContext.start(); // 컨텍스트 다시 시작
+            log.info("Logback context has been reset. New log file will be created.");
+        } catch (JoranException e) {
+            log.error("Failed to reset Logback context", e);
+        }
+    }
+
+    private void mergeLogsFromS3(File localFile, File tempFile, String s3Key) throws IOException {
+        try (S3Object s3Object = amazonS3.getObject(new GetObjectRequest(bucket, s3Key));
+             InputStream s3InputStream = s3Object.getObjectContent();
+             OutputStream tempOutputStream = new FileOutputStream(tempFile, true);
+             InputStream localInputStream = new FileInputStream(localFile)) {
+
+            // S3 로그 내용을 임시 파일에 복사
+            copyContent(s3InputStream, tempOutputStream);
+
+            // 로컬 로그 내용을 임시 파일에 이어서 복사
+            copyContent(localInputStream, tempOutputStream);
+        }
+    }
+
+    private void copyContent(InputStream input, OutputStream output) throws IOException {
+        byte[] buffer = new byte[1024];
+        int bytesRead;
+        while ((bytesRead = input.read(buffer)) > 0) {
+            output.write(buffer, 0, bytesRead);
         }
     }
 
     private File getLocalLogFile(String day) {
-        // LOG_HOME=/var/app/current/logs
         String logHome = System.getProperty("LOG_HOME", "./logs");
         LocalDate targetDate = "yesterday".equals(day) ? LocalDate.now().minusDays(1) : LocalDate.now();
-        String dateStr = targetDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
+        String dateStr = targetDate.format(LOG_DATE_FORMAT);
 
         if ("yesterday".equals(day)) {
-            // 롤오버된 파일: /var/app/current/logs/error-2025-01-01.log
             return new File(logHome, "error-" + dateStr + ".log");
         } else {
-            // 아직 열려 있는 로그: /var/app/current/logs/error.log
             return new File(logHome, "error.log");
         }
     }
 
     private String buildS3Key(String day) {
-        // 원하는 규칙대로 S3에 업로드될 파일 키 생성
         LocalDate targetDate = "yesterday".equals(day) ? LocalDate.now().minusDays(1) : LocalDate.now();
-        String dateStr = targetDate.format(DateTimeFormatter.ofPattern("yyyy-MM-dd"));
+        String dateStr = targetDate.format(LOG_DATE_FORMAT);
 
         String activeProfile = environment.getProperty("spring.profiles.active", "default");
 
-        return String.format("logs/" + activeProfile + "/" + activeProfile + "-error-%s.log", dateStr);
+        return String.format("logs/%s/%s-error-%s.log", activeProfile, activeProfile, dateStr);
     }
 }

src/main/java/LuckyVicky/backend/global/scheduler/LogUploadScheduler.java

@@ -15,8 +15,8 @@ public class LogUploadScheduler {
 
     @Scheduled(cron = "0 0 0 * * ?", zone = "Asia/Seoul")
     public void uploadDailyLogToS3() {
-        log.error("Uploading Log to S3 with Scheduler");
+        log.info("Uploading Log to S3 with Scheduler");
         logService.uploadDailyLog("yesterday");
-        log.error("Uploaded Log to S3 with Scheduler");
+        log.info("Uploaded Log to S3 with Scheduler");
     }
 }

src/main/java/LuckyVicky/backend/global/util/Constant.java

@@ -11,9 +11,6 @@ public class Constant {
     private String fcmProjectId;
 
     // Log
-    public static final String LOG_S3_DIRECTORY = "logs/";
-    public static final String LOG_LOCAL_FILE_DIRECTORY = "src/main/resources/logs/";
-    public static final String LOG_LOCAL_ERROR_FILE_NAME = "error.log";
     public static final String LOG_LOGBACK_FILE_DIRECTORY = "src/main/resources/";
     public static final String LOG_LOGBACK_ERROR_FILE_NAME = "logback-spring.xml";