Fix for redis rate limiter not working with multiple routes. Fixes gh-2288 (#2517)

Author: muchnik

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/ratelimit/RedisRateLimiter.java

@@ -48,6 +48,7 @@
  * @author Spencer Gibb
  * @author Ronny Bräunlich
  * @author Denis Cutic
+ * @author Andrey Muchnik
  */
 @ConfigurationProperties("spring.cloud.gateway.redis-rate-limiter")
 public class RedisRateLimiter extends AbstractRateLimiter<RedisRateLimiter.Config> implements ApplicationContextAware {
@@ -145,16 +146,16 @@ public RedisRateLimiter(int defaultReplenishRate, int defaultBurstCapacity, int
 		this.defaultConfig.setRequestedTokens(defaultRequestedTokens);
 	}
 
-	static List<String> getKeys(String id) {
+	static List<String> getKeys(String id, String routeId) {
 		// use `{}` around keys to use Redis Key hash tags
 		// this allows for using redis cluster
 
-		// Make a unique key per user.
-		String prefix = "request_rate_limiter.{" + id;
+		// Make a unique key per user and route.
+		String prefix = "request_rate_limiter.{" + routeId + "." + id + "}.";
 
 		// You need two Redis keys for Token Bucket.
-		String tokenKey = prefix + "}.tokens";
-		String timestampKey = prefix + "}.timestamp";
+		String tokenKey = prefix + "tokens";
+		String timestampKey = prefix + "timestamp";
 		return Arrays.asList(tokenKey, timestampKey);
 	}
 
@@ -245,7 +246,7 @@ public Mono<Response> isAllowed(String routeId, String id) {
 		int requestedTokens = routeConfig.getRequestedTokens();
 
 		try {
-			List<String> keys = getKeys(id);
+			List<String> keys = getKeys(id, routeId);
 
 			// The arguments to the LUA script. time() returns unixtime in seconds.
 			List<String> scriptArgs = Arrays.asList(replenishRate + "", burstCapacity + "", "", requestedTokens + "");

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/filter/ratelimit/RedisRateLimiterTests.java

@@ -51,6 +51,7 @@
  * @author Spencer Gibb
  * @author Ronny Bräunlich
  * @author Denis Cutic
+ * @author Andrey Muchnik
  */
 @SpringBootTest(webEnvironment = RANDOM_PORT)
 @DirtiesContext
@@ -98,6 +99,30 @@ public void redisRateLimiterWorks() throws Exception {
 		checkLimitEnforced(id, replenishRate, burstCapacity, requestedTokens, routeId);
 	}
 
+
+	@Test
+	public void redisRateLimiterWorksForMultipleRoutes() throws Exception {
+		String id = UUID.randomUUID().toString();
+
+		int replenishRate = 10;
+		int burstCapacity = 2 * replenishRate;
+		int requestedTokens = 1;
+
+		String firstRouteId = "myroute";
+		String secondRouteId = "myroute2";
+		var config = rateLimiter.getConfig();
+		config.put(firstRouteId, new RedisRateLimiter.Config().setBurstCapacity(burstCapacity)
+															  .setReplenishRate(replenishRate)
+															  .setRequestedTokens(requestedTokens));
+
+		config.put(secondRouteId, new RedisRateLimiter.Config().setBurstCapacity(burstCapacity)
+															   .setReplenishRate(replenishRate)
+															   .setRequestedTokens(requestedTokens));
+
+		checkLimitEnforced(id, replenishRate, burstCapacity, requestedTokens, firstRouteId);
+		checkLimitEnforced(id, replenishRate, burstCapacity, requestedTokens, secondRouteId);
+	}
+
 	@Test
 	public void redisRateLimiterWorksForLowRates() throws Exception {
 		String id = UUID.randomUUID().toString();
@@ -137,8 +162,8 @@ public void redisRateLimiterWorksForZeroBurstCapacity() throws Exception {
 
 	@Test
 	public void keysUseRedisKeyHashTags() {
-		assertThat(RedisRateLimiter.getKeys("1")).containsExactly("request_rate_limiter.{1}.tokens",
-				"request_rate_limiter.{1}.timestamp");
+		assertThat(RedisRateLimiter.getKeys("1", "routeId")).containsExactly("request_rate_limiter.{routeId.1}.tokens",
+				"request_rate_limiter.{routeId.1}.timestamp");
 	}
 
 	@Test