[SDR-433] BE: Redis를 활용한 공통으로 사용할 수 있는 Rate Limiter Service 구현

be/build.gradle

@@ -57,6 +57,7 @@ dependencies {
     implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
     runtimeOnly 'com.h2database:h2'
     runtimeOnly 'mysql:mysql-connector-java'
+    implementation 'org.springframework.boot:spring-boot-starter-data-redis'
 
     // Dev
     compileOnly 'org.projectlombok:lombok'

be/src/main/java/com/jjikmuk/sikdorak/common/config/RedisConfig.java

@@ -0,0 +1,40 @@
+package com.jjikmuk.sikdorak.common.config;
+
+import com.jjikmuk.sikdorak.common.properties.RedisProperties;
+import lombok.RequiredArgsConstructor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.connection.RedisConnectionFactory;
+import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.serializer.StringRedisSerializer;
+import org.springframework.orm.jpa.JpaTransactionManager;
+import org.springframework.transaction.PlatformTransactionManager;
+
+@Configuration
+@RequiredArgsConstructor
+public class RedisConfig {
+
+	private final RedisProperties redisProperties;
+
+	@Bean
+	public RedisConnectionFactory redisConnectionFactory() {
+		return new LettuceConnectionFactory(redisProperties.getHost(), redisProperties.getPort());
+	}
+
+	@Bean
+	public StringRedisTemplate stringRedisTemplate() {
+		StringRedisTemplate stringRedisTemplate = new StringRedisTemplate();
+		stringRedisTemplate.setConnectionFactory(redisConnectionFactory());
+		stringRedisTemplate.setKeySerializer(new StringRedisSerializer());
+		stringRedisTemplate.setValueSerializer(new StringRedisSerializer());
+		stringRedisTemplate.setEnableTransactionSupport(true);
+		return stringRedisTemplate;
+	}
+
+	@Bean
+	public PlatformTransactionManager transactionManager()  {
+		return new JpaTransactionManager();
+	}
+
+}

be/src/main/java/com/jjikmuk/sikdorak/common/exception/ExceptionCodeAndMessages.java

@@ -9,6 +9,7 @@
 import com.jjikmuk.sikdorak.image.exception.InvalidImagesExtensionException;
 import com.jjikmuk.sikdorak.image.exception.NotFoundImageException;
 import com.jjikmuk.sikdorak.image.exception.NotFoundImageMetaDataException;
+import com.jjikmuk.sikdorak.ratelimit.exception.ApiLimitExceededException;
 import com.jjikmuk.sikdorak.review.exception.DuplicateLikeUserException;
 import com.jjikmuk.sikdorak.review.exception.InvalidReviewContentException;
 import com.jjikmuk.sikdorak.review.exception.InvalidReviewImageException;
@@ -53,6 +54,7 @@ public enum ExceptionCodeAndMessages implements CodeAndMessages {
     NOT_FOUND_ERROR_CODE("F-G001", "에러 코드를 찾을 수 없습니다.", NotFoundErrorCodeException.class),
     INVALID_PAGE_PARAMETER("F-G002", "유효하지 않은 페이징 값 입니다.", InvalidPageParameterException.class),
     INTERNAL_SERVER_ERROR("F-G003", "서버 에러입니다.(관리자에게 문의하세요)", SikdorakServerError.class),
+    API_LIMIT_EXCEEDED("F-G004", "너무 많은 요청을 하였습니다.", ApiLimitExceededException.class),
 
     // Review
     INVALID_REVIEW_CONTENT("F-R001", "유효하지 않은 리뷰 컨텐츠 입니다.", InvalidReviewContentException.class),

be/src/main/java/com/jjikmuk/sikdorak/common/properties/RedisProperties.java

@@ -0,0 +1,28 @@
+package com.jjikmuk.sikdorak.common.properties;
+
+import javax.validation.constraints.NotEmpty;
+import javax.validation.constraints.NotNull;
+import lombok.Getter;
+import org.hibernate.validator.constraints.Range;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.ConstructorBinding;
+import org.springframework.validation.annotation.Validated;
+
+@Getter
+@Validated
+@ConstructorBinding
+@ConfigurationProperties(prefix = "spring.redis")
+public class RedisProperties {
+
+	@NotEmpty
+	private final String host;
+
+	@NotNull
+	@Range(min = 0, max = 65535)
+	private final int port;
+
+	public RedisProperties(String host, int port) {
+		this.host = host;
+		this.port = port;
+	}
+}

be/src/main/java/com/jjikmuk/sikdorak/ratelimit/command/app/ApiRateLimiterService.java

@@ -0,0 +1,9 @@
+package com.jjikmuk.sikdorak.ratelimit.command.app;
+
+import javax.servlet.http.HttpServletRequest;
+
+public interface ApiRateLimiterService {
+
+	Boolean checkRateLimit(HttpServletRequest request, long windowSize, long apiMaximumNumber);
+
+}

be/src/main/java/com/jjikmuk/sikdorak/ratelimit/command/app/RedisApiRateLimiterService.java

@@ -0,0 +1,147 @@
+package com.jjikmuk.sikdorak.ratelimit.command.app;
+
+import com.jjikmuk.sikdorak.ratelimit.exception.ApiLimitExceededException;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.List;
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+import javax.servlet.http.HttpServletRequest;
+import lombok.RequiredArgsConstructor;
+import org.springframework.dao.DataAccessException;
+import org.springframework.data.redis.core.RedisOperations;
+import org.springframework.data.redis.core.SessionCallback;
+import org.springframework.data.redis.core.StringRedisTemplate;
+import org.springframework.data.redis.core.ValueOperations;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class RedisApiRateLimiterService implements ApiRateLimiterService {
+
+	private final StringRedisTemplate redisTemplate;
+
+	/**
+	 * Redis 저장소를 활용하여 Rate Limit 여부를 확인한다.
+	 * Redis Key Format - API:ip:yyyyMMddHHmm , e.g. /api/images/url:127.0.0.1:202212161449
+	 * API 사용 가능한 경우 해당 key의 값을 1 증가시킨다.
+	 * 불가능한 경우 Exception을 발생시킨다.
+	 * 알고리즘 : Sliding Window Counter
+	 *
+	 * @param request 클라이언트의 ip, servlet path를 사용한다.
+	 * @param windowSize api 사용 빈도 검색 시간 범위 & Redis Key expire time, 단위는 '분(minute)'이다.
+	 * @param apiMaximumNumber windowSize 내 최대 api 요청수
+	 * @return true : api 사용 가능
+	 */
+	@Override
+	public Boolean checkRateLimit(HttpServletRequest request, long windowSize, long apiMaximumNumber) {
+		Date currentDate = new Date();
+		String apiPathAndIpKey = getApiPathAndIpKey(request);
+
+		long totalApiCounts = findTotalApiCounts(apiPathAndIpKey, currentDate, windowSize);
+
+		// 검증
+		if (totalApiCounts < apiMaximumNumber) {
+			upsertApiCount(apiPathAndIpKey, currentDate, windowSize);
+			return true;
+		}
+
+		throw new ApiLimitExceededException();
+	}
+
+	private String getApiPathAndIpKey(HttpServletRequest request) {
+		String servletPath = request.getServletPath();
+		String clientIp = getClientIp(request); // ip 가져올 때 ipv4 vs ipv6
+
+		StringBuilder sb = new StringBuilder();
+		sb.append(servletPath).append(":").append(clientIp).append(":");
+
+		return sb.toString();
+	}
+
+	/**
+	 * 클라이언트의 ip 주소를 추출한다.
+	 * ref : <a href="https://www.lesstif.com/software-architect/proxy-client-ip-x-forwarded-for-xff-http-header-20775886.html">...</a>.
+	 *
+	 * @param request Client의 HttpServletRequest
+	 * @return Client Ip
+	 */
+	private String getClientIp(HttpServletRequest request) {
+		String ip = request.getHeader("X-Forwarded-For");
+		String unknown = "unknown";
+		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
+			ip = request.getHeader("Proxy-Client-IP");
+		}
+		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
+			ip = request.getHeader("WL-Proxy-Client-IP");
+		}
+		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
+			ip = request.getHeader("HTTP_CLIENT_IP");
+		}
+		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
+			ip = request.getHeader("HTTP_X_FORWARDED_FOR");
+		}
+		if (ip == null || ip.length() == 0 || unknown.equalsIgnoreCase(ip)) {
+			ip = request.getRemoteAddr();
+		}
+
+		return ip;
+	}
+
+	/**
+	 * 현재 시간부터 windowSize 이전까지의 시간의 api counts 총합을 리턴합니다.
+	 *
+	 * @param apiPathAndIpKey - /api/images/url:127.0.0.1
+	 * @param currentDate - 현재 시간의 Date 객체
+	 * @param windowSize - api 사용 빈도 검색 시간 범위
+	 * @return totalApiCounts
+	 */
+	private long findTotalApiCounts(String apiPathAndIpKey, Date currentDate, long windowSize) {
+		// 현재 시간 key 기준 검색할 key List e.g. 202212161449, 202212161448, 202212161447 ...
+		List<String> searchRateLimitKeys = new ArrayList<>();
+		Calendar calendar = Calendar.getInstance();
+		calendar.setTime(currentDate);
+		for (int i = 0; i < windowSize; i++) {
+			searchRateLimitKeys.add(apiPathAndIpKey + new SimpleDateFormat("yyyyMMddHHmm").format(calendar.getTime()));
+			calendar.add(Calendar.MINUTE, -1);
+		}
+
+		// 전체 카운트 조회
+		ValueOperations<String, String> valueOperations = redisTemplate.opsForValue();
+		List<String> values = valueOperations.multiGet(searchRateLimitKeys);
+		long totalCounts = 0L;
+		for (String value : Objects.requireNonNull(values)) {
+			if (Objects.nonNull(value)) {
+				totalCounts = totalCounts + Long.parseLong(value);
+			}
+		}
+
+		return totalCounts;
+	}
+
+	/**
+	 * Redis Key의 value를 1 증가 시키고 expire time을 설정한다.
+	 *
+	 * @param apiPathAndIpKey - /api/images/url:127.0.0.1
+	 * @param currentDate - 현재 시간의 Date 객체
+	 * @param windowSize - api 사용 빈도 검색 시간 범위 & Redis Key expire time
+	 */
+	private void upsertApiCount(String apiPathAndIpKey, Date currentDate, long windowSize) {
+		String currentRateLimitKey =
+			apiPathAndIpKey + new SimpleDateFormat("yyyyMMddHHmm").format(currentDate);
+
+		redisTemplate.execute(new SessionCallback<>() {
+			@Override
+			public <K, V> Object execute(RedisOperations<K, V> operations)
+				throws DataAccessException {
+
+				operations.multi();
+				operations.opsForValue().increment((K) currentRateLimitKey);
+				operations.expire((K) currentRateLimitKey, windowSize, TimeUnit.MINUTES);
+				return operations.exec();
+			}
+		});
+	}
+}

be/src/main/java/com/jjikmuk/sikdorak/ratelimit/exception/ApiLimitExceededException.java

@@ -0,0 +1,12 @@
+package com.jjikmuk.sikdorak.ratelimit.exception;
+
+import com.jjikmuk.sikdorak.common.exception.SikdorakRuntimeException;
+import org.springframework.http.HttpStatus;
+
+public class ApiLimitExceededException extends SikdorakRuntimeException {
+
+	@Override
+	public HttpStatus getHttpStatus() {
+		return HttpStatus.TOO_MANY_REQUESTS;
+	}
+}

be/src/test/java/com/jjikmuk/sikdorak/integration/InitIntegrationTest.java

@@ -8,12 +8,29 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.testcontainers.containers.GenericContainer;
 
 
 @SpringBootTest(classes = AWSMockConfig.class)
 @ActiveProfiles("test")
 public abstract class InitIntegrationTest {
 
+	static final GenericContainer redis;
+
+	static {
+		redis = new GenericContainer("redis:7.0.5")
+			.withExposedPorts(6379);
+		redis.start();
+	}
+
+	@DynamicPropertySource
+	public static void overrideProps(DynamicPropertyRegistry registry) {
+		registry.add("spring.redis.host", redis::getHost);
+		registry.add("spring.redis.port", () -> redis.getMappedPort(6379));
+	}
+
 	@Autowired
 	protected DatabaseConfigurator testData;