io.micronaut.configuration.ribbon.discovery.RibbonServiceInstanceListLoadBalancerFactory Maven / Gradle / Ivy

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/*
 * Copyright 2017-2018 original 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
 *
 * http://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 io.micronaut.configuration.ribbon.discovery;

import com.netflix.client.config.CommonClientConfigKey;
import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.AbstractServerList;
import com.netflix.loadbalancer.IPing;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.Server;
import com.netflix.loadbalancer.ServerList;
import com.netflix.loadbalancer.ServerListFilter;
import io.micronaut.configuration.ribbon.RibbonLoadBalancer;
import io.micronaut.configuration.ribbon.RibbonServer;
import io.micronaut.context.BeanContext;
import io.micronaut.context.annotation.Replaces;
import io.micronaut.context.env.Environment;
import io.micronaut.discovery.ServiceInstance;
import io.micronaut.discovery.ServiceInstanceList;
import io.micronaut.http.client.LoadBalancer;
import io.micronaut.http.client.loadbalance.ServiceInstanceListLoadBalancerFactory;
import io.micronaut.inject.qualifiers.Qualifiers;

import javax.inject.Singleton;
import java.util.List;
import java.util.stream.Collectors;

/**
 * Replaces the default {@link ServiceInstanceListLoadBalancerFactory} with one that returns {@link RibbonLoadBalancer} instances.
 *
 * @author graemerocher
 * @since 1.0
 */
@Singleton
@Replaces(ServiceInstanceListLoadBalancerFactory.class)
public class RibbonServiceInstanceListLoadBalancerFactory extends ServiceInstanceListLoadBalancerFactory {
    private final BeanContext beanContext;
    private final IClientConfig defaultClientConfig;
    private final Environment environment;

    /**
     * Constructor.
     * @param beanContext beanContext
     * @param defaultClientConfig defaultClientConfig
     * @param environment The environment
     */
    public RibbonServiceInstanceListLoadBalancerFactory(BeanContext beanContext, IClientConfig defaultClientConfig, Environment environment) {
        this.beanContext = beanContext;
        this.defaultClientConfig = defaultClientConfig;
        this.environment = environment;
    }

    @Override
    public LoadBalancer create(ServiceInstanceList serviceInstanceList) {
        String serviceID = serviceInstanceList.getID();

        // create the client config
        IClientConfig niwsClientConfig = beanContext.findBean(IClientConfig.class, Qualifiers.byName(serviceID))
                                                    .orElse(new StandardNameClientConfig(environment, serviceID, defaultClientConfig));

        // create the rule
        IRule rule = beanContext.findBean(IRule.class, Qualifiers.byName(serviceID))
                                .orElseGet(() -> beanContext.createBean(IRule.class));

        // create the ping
        IPing ping = beanContext.findBean(IPing.class, Qualifiers.byName(serviceID))
                                .orElseGet(() -> beanContext.createBean(IPing.class));

        // create the server list
        ServerListFilter serverListFilter = beanContext.findBean(
                ServerListFilter.class,
                Qualifiers.byName(serviceID))
                .orElseGet(() -> beanContext.createBean(ServerListFilter.class));

        ServerList serverList = beanContext.findBean(ServerList.class, Qualifiers.byName(serviceID))
                                                   .orElseGet(() -> toRibbonServerList(serviceInstanceList));

        if (niwsClientConfig.getPropertyAsBoolean(CommonClientConfigKey.InitializeNFLoadBalancer, true)) {
            return createRibbonLoadBalancer(
                    niwsClientConfig,
                    rule,
                    ping,
                    serverListFilter,
                    serverList
            );
        } else {
            return super.create(serviceInstanceList);
        }
    }

    private ServerList toRibbonServerList(ServiceInstanceList serviceInstanceList) {
        return new AbstractServerList() {
            @Override
            public void initWithNiwsConfig(IClientConfig clientConfig) {

            }

            @Override
            public List getInitialListOfServers() {
                List instances = serviceInstanceList.getInstances();
                return instances.stream().map(RibbonServer::new).collect(Collectors.toList());
            }

            /**
             * Get an updated list of servers.
             * @return list of servers.
             */
            @Override
            public List getUpdatedListOfServers() {
                return getInitialListOfServers();
            }
        };
    }

    /**
     * Create the load balancer based on the parameters.
     * @param niwsClientConfig niwsClientConfig
     * @param rule rule
     * @param ping ping
     * @param serverListFilter serverListFilter
     * @param serverList serverList
     * @return balancer
     */
    protected RibbonLoadBalancer createRibbonLoadBalancer(
            IClientConfig niwsClientConfig,
            IRule rule,
            IPing ping,
            ServerListFilter serverListFilter,
            ServerList serverList) {
        return new RibbonLoadBalancer(
            niwsClientConfig,
            serverList,
            serverListFilter,
            rule,
            ping
        );
    }
}