org.springframework.cloud.gateway.sample.ThrottleGatewayFilter.java Source code

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Here is the source code for org.springframework.cloud.gateway.sample.ThrottleGatewayFilter.java

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/*
 * Copyright 2013-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.cloud.gateway.sample;

import java.util.concurrent.TimeUnit;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.isomorphism.util.TokenBucket;
import org.isomorphism.util.TokenBuckets;
import reactor.core.publisher.Mono;

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.http.HttpStatus;
import org.springframework.web.server.ServerWebExchange;

/**
 * Sample throttling filter. See https://github.com/bbeck/token-bucket
 */
public class ThrottleGatewayFilter implements GatewayFilter {

    private static final Log log = LogFactory.getLog(ThrottleGatewayFilter.class);

    int capacity;

    int refillTokens;

    int refillPeriod;

    TimeUnit refillUnit;

    public int getCapacity() {
        return capacity;
    }

    public ThrottleGatewayFilter setCapacity(int capacity) {
        this.capacity = capacity;
        return this;
    }

    public int getRefillTokens() {
        return refillTokens;
    }

    public ThrottleGatewayFilter setRefillTokens(int refillTokens) {
        this.refillTokens = refillTokens;
        return this;
    }

    public int getRefillPeriod() {
        return refillPeriod;
    }

    public ThrottleGatewayFilter setRefillPeriod(int refillPeriod) {
        this.refillPeriod = refillPeriod;
        return this;
    }

    public TimeUnit getRefillUnit() {
        return refillUnit;
    }

    public ThrottleGatewayFilter setRefillUnit(TimeUnit refillUnit) {
        this.refillUnit = refillUnit;
        return this;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {

        TokenBucket tokenBucket = TokenBuckets.builder().withCapacity(capacity)
                .withFixedIntervalRefillStrategy(refillTokens, refillPeriod, refillUnit).build();

        // TODO: get a token bucket for a key
        log.debug("TokenBucket capacity: " + tokenBucket.getCapacity());
        boolean consumed = tokenBucket.tryConsume();
        if (consumed) {
            return chain.filter(exchange);
        }
        exchange.getResponse().setStatusCode(HttpStatus.TOO_MANY_REQUESTS);
        return exchange.getResponse().setComplete();
    }

}