Initial move off of lua

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -19,7 +19,6 @@ package org.springframework.cloud.gateway.config;
 
 import java.util.List;
 
-import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.actuate.endpoint.Endpoint;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
@@ -78,18 +77,12 @@ import org.springframework.cloud.gateway.route.RouteLocator;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
-import org.springframework.core.io.ClassPathResource;
-import org.springframework.data.redis.core.RedisTemplate;
-import org.springframework.data.redis.core.StringRedisTemplate;
-import org.springframework.data.redis.core.script.DefaultRedisScript;
-import org.springframework.data.redis.core.script.RedisScript;
-import org.springframework.scripting.support.ResourceScriptSource;
+import org.springframework.data.redis.core.ReactiveRedisTemplate;
 
 import com.netflix.hystrix.HystrixObservableCommand;
 
 import reactor.core.publisher.Flux;
 import reactor.ipc.netty.http.client.HttpClient;
-import reactor.ipc.netty.resources.PoolResources;
 import rx.RxReactiveStreams;
 
 /**
@@ -109,8 +102,8 @@ public class GatewayAutoConfiguration {
 		@ConditionalOnMissingBean
 		public HttpClient httpClient() {
 			return HttpClient.create(opts -> {
-				opts.poolResources(PoolResources.elastic("proxy"));
-				// opts.disablePool(); //TODO: why do I need this again?
+				// opts.poolResources(PoolResources.elastic("proxy"));
+				opts.disablePool(); //TODO: why do I need this again?
 			});
 		}
 
@@ -321,20 +314,11 @@ public class GatewayAutoConfiguration {
 	}
 
 
-	@ConditionalOnClass(RedisTemplate.class)
+	@ConditionalOnClass(ReactiveRedisTemplate.class)
 	protected static class GatewayRedisConfiguration {
 		@Bean
-		public RedisScript<List> redistRequestRateLimiterScript() {
-			DefaultRedisScript<List> redisScript = new DefaultRedisScript<>();
-			redisScript.setScriptSource(new ResourceScriptSource(new ClassPathResource("META-INF/scripts/request_rate_limiter.lua")));
-			redisScript.setResultType(List.class);
-			return redisScript;
-		}
-
-		@Bean
-		public RedisRateLimiter redisRateLimiter(StringRedisTemplate redisTemplate,
-												 @Qualifier("redistRequestRateLimiterScript") RedisScript<List> redisScript) {
-			return new RedisRateLimiter(redisTemplate, redisScript);
+		public RedisRateLimiter redisRateLimiter(ReactiveRedisTemplate<Object, Object> redisTemplate) {
+			return new RedisRateLimiter(redisTemplate);
 		}
 	}
 

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/ratelimit/RateLimiter.java

@@ -4,7 +4,7 @@ package org.springframework.cloud.gateway.filter.ratelimit;
  * @author Spencer Gibb
  */
 public interface RateLimiter {
-	Response isAllowed(String id, int replenishRate, int burstCapacity);
+	Response isAllowed(String id, long replenishRate, long burstCapacity);
 
 	class Response {
 		private final boolean allowed;

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

@@ -1,14 +1,20 @@
 package org.springframework.cloud.gateway.filter.ratelimit;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
-import org.springframework.data.redis.core.StringRedisTemplate;
-import org.springframework.data.redis.core.script.RedisScript;
-
+import java.time.Duration;
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.data.redis.core.ReactiveRedisTemplate;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.util.function.Tuple2;
+
 /**
  * See https://stripe.com/blog/rate-limiters and
  * https://gist.github.com/ptarjan/e38f45f2dfe601419ca3af937fff574d#file-1-check_request_rate_limiter-rb-L11-L34
@@ -18,12 +24,10 @@ import java.util.List;
 public class RedisRateLimiter implements RateLimiter {
 	private Log log = LogFactory.getLog(getClass());
 
-	private final StringRedisTemplate redisTemplate;
-	private final RedisScript<List> script;
+	private final ReactiveRedisTemplate<Object, Object> redisTemplate;
 
-	public RedisRateLimiter(StringRedisTemplate redisTemplate, RedisScript<List> script) {
+	public RedisRateLimiter(ReactiveRedisTemplate<Object, Object> redisTemplate) {
 		this.redisTemplate = redisTemplate;
-		this.script = script;
 	}
 
 	/**
@@ -37,29 +41,77 @@ public class RedisRateLimiter implements RateLimiter {
 	@Override
 	//TODO: signature? params (tuple?).
 	//TODO: change to Mono<?>
-	public Response isAllowed(String id, int replenishRate, int burstCapacity) {
+	public Response isAllowed(String id, long replenishRate, long burstCapacity) {
 
 		try {
 			// Make a unique key per user.
-			String prefix = "request_rate_limiter." + id;
+			String key = "request_rate_limiter." + id;
 
 			// You need two Redis keys for Token Bucket.
-			List<String> keys = Arrays.asList(prefix + ".tokens", prefix + ".timestamp");
+			// String tokensKey = key + ".tokens";
+			// String timestampKey = key + ".timestamp";
 
 			// The arguments to the LUA script. time() returns unixtime in seconds.
-			Object[] args = new String[]{ replenishRate+"", burstCapacity +"", Instant.now().getEpochSecond()+"", "1"};
-			// allowed, tokens_left = redis.eval(SCRIPT, keys, args)
-			List results = this.redisTemplate.execute(this.script, keys, args);
+			long now = Instant.now().getEpochSecond();
+			int requested = 1;
 
-			boolean allowed = new Long(1L).equals(results.get(0));
-			Long tokensLeft = (Long) results.get(1);
+			double fillTime = (double)burstCapacity / (double)replenishRate;
+			int ttl = (int)Math.floor(fillTime * 2);
 
-			Response response = new Response(allowed, tokensLeft);
+			Mono<Boolean> booleanMono = this.redisTemplate.hasKey(key);
+			Boolean hasKey = booleanMono.block();
 
-			if (log.isDebugEnabled()) {
-				log.debug("response: "+response);
+			Mono<List<Object>> valuesMono;
+			if (hasKey) {
+				valuesMono = this.redisTemplate.opsForHash().multiGet(key, Arrays.asList("tokens", "timestamp"));
+			} else {
+				valuesMono = Mono.just(new ArrayList<>());
 			}
-			return response;
+			Mono<Response> responseMono = valuesMono.map(objects -> {
+				Long lastTokens = null;
+
+				if (objects.size() >= 1) {
+					lastTokens= (Long) objects.get(0);
+				}
+				if (lastTokens == null) {
+					lastTokens = burstCapacity;
+				}
+
+				Long lastRefreshed = null;
+				if (objects.size() >= 2) {
+					lastRefreshed = (Long) objects.get(1);
+				}
+				if (lastRefreshed == null) {
+					lastRefreshed = 0L;
+				}
+
+				long delta = Math.max(0, (now - lastRefreshed));
+				long filledTokens = Math.min(burstCapacity, lastTokens + (delta * replenishRate));
+				boolean allowed = filledTokens >= requested;
+				long newTokens = filledTokens;
+				if (allowed) {
+					newTokens = filledTokens - requested;
+				}
+
+				HashMap<Object, Object> updated = new HashMap<>();
+				updated.put("tokens", newTokens);
+				updated.put("timestamp", now);
+				Mono<Boolean> putAllMono = this.redisTemplate.opsForHash().putAll(key, updated);
+				Mono<Boolean> expireMono = this.redisTemplate.expire(key, Duration.ofSeconds(ttl));
+
+				Flux<Tuple2<Boolean, Boolean>> zip = Flux.zip(putAllMono, expireMono);
+				Tuple2<Boolean, Boolean> objects1 = zip.blockLast();
+
+				Response response = new Response(allowed, newTokens);
+
+				if (log.isDebugEnabled()) {
+					log.debug("response: " + response);
+				}
+
+				return response;
+			});
+
+			return responseMono.block();
 
 		} catch (Exception e) {
 			/* We don't want a hard dependency on Redis to allow traffic.

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

@@ -33,7 +33,7 @@ public class RedisRateLimiterTests extends BaseWebClientTests {
 	public void requestRateLimiterWebFilterFactoryWorks() throws Exception {
 		String id = UUID.randomUUID().toString();
 
-		int replenishRate = 10;
+		int replenishRate = 1;//10;
 		int burstCapacity = 2 * replenishRate;
 
 		// Bursts work