com.tencent.cloud.polaris.loadbalancer.AbstractPolarisRule Maven / Gradle / Ivy

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/*
 * Tencent is pleased to support the open source community by making Spring Cloud Tencent available.
 *
 * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
 *
 * Licensed under the BSD 3-Clause License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://opensource.org/licenses/BSD-3-Clause
 *
 * 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 com.tencent.cloud.polaris.loadbalancer;

import java.util.List;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractServerPredicate;
import com.netflix.loadbalancer.AvailabilityPredicate;
import com.netflix.loadbalancer.CompositePredicate;
import com.netflix.loadbalancer.PredicateBasedRule;
import com.netflix.loadbalancer.Server;
import com.tencent.cloud.common.pojo.PolarisServer;
import com.tencent.polaris.api.pojo.Instance;
import com.tencent.polaris.api.pojo.ServiceInstances;
import com.tencent.polaris.router.api.core.RouterAPI;
import com.tencent.polaris.router.api.rpc.ProcessLoadBalanceRequest;
import com.tencent.polaris.router.api.rpc.ProcessLoadBalanceResponse;

import org.springframework.util.CollectionUtils;

/**
 * Abstract polaris load balancer rule.
 *
 * @author veteranchen
 */
public abstract class AbstractPolarisRule extends PredicateBasedRule {
	private final RouterAPI routerAPI;
	private CompositePredicate compositePredicate;

	public AbstractPolarisRule(RouterAPI routerAPI) {
		this.routerAPI = routerAPI;
	}

	@Override
	public void initWithNiwsConfig(IClientConfig clientConfig) {
		AvailabilityPredicate availabilityPredicate = new AvailabilityPredicate(this, clientConfig);
		compositePredicate = CompositePredicate.withPredicates(availabilityPredicate).build();
	}

	@Override
	public AbstractServerPredicate getPredicate() {
		return compositePredicate;
	}

	@Override
	public Server choose(Object key) {
		List servers = getLoadBalancer().getReachableServers();
		if (CollectionUtils.isEmpty(servers)) {
			return null;
		}

		// filter circuit breaker servers by ribbon
		if (compositePredicate != null) {
			servers = compositePredicate.getEligibleServers(servers);
		}

		ServiceInstances serviceInstances = LoadBalancerUtils.transferServersToServiceInstances(servers);
		ProcessLoadBalanceRequest request = new ProcessLoadBalanceRequest();
		request.setDstInstances(serviceInstances);
		request = setProcessLoadBalanceRequest(request);
		ProcessLoadBalanceResponse processLoadBalanceResponse = routerAPI.processLoadBalance(request);
		Instance targetInstance = processLoadBalanceResponse.getTargetInstance();
		return new PolarisServer(serviceInstances, targetInstance);
	}

	protected abstract ProcessLoadBalanceRequest setProcessLoadBalanceRequest(ProcessLoadBalanceRequest request);
}