[chore] 인증 로직 로그 추가 (#255)

Author: LeeMinwoo115

backend/src/main/java/com/back/global/security/CustomAuthenticationFilter.java

@@ -157,6 +157,7 @@ private void handleErrorException(
 			cookieManager.deleteAuthCookies(request, response);
 		}
 
+		log.error("CustomAuthenticationFilter: ", error);
 		writeError(response, error.getErrorCode());
 	}
 
@@ -200,6 +201,8 @@ private String ensureValidAccessToken(
 			return accessToken;
 		}
 
+		log.info("Expired Access Token → Try to Issue new Access Token, expired access token: {}",
+			accessToken);
 		String refreshTokenStr = resolveCookie(request, CookieManager.REFRESH_TOKEN_COOKIE);
 
 		if (StringUtils.isBlank(refreshTokenStr) || jwtProvider.isExpired(refreshTokenStr)) {

backend/src/main/java/com/back/global/security/JwtProvider.java

@@ -13,9 +13,11 @@
 import com.back.global.utils.JwtUtil;
 
 import lombok.Getter;
+import lombok.extern.slf4j.Slf4j;
 
 @Component
 @Getter
+@Slf4j
 public class JwtProvider {
 
 	@Value("${custom.jwt.secret}")
@@ -59,6 +61,7 @@ private String generateToken(
 		claims.put(CLAIM_SESSION_ID, sessionId);
 		claims.put(CLAIM_TOKEN_VERSION, tokenVersion);
 
+		log.info("Generate Token({}), userId: {}", tokenType, user.getId());
 		return JwtUtil.sign(secret, durationSeconds, claims);
 	}