cn.ponfee.disjob.registry.discovery.ServerDiscovery Maven / Gradle / Ivy

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/*
 * Copyright 2022-2024 Ponfee (http://www.ponfee.cn/)
 *
 * 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 cn.ponfee.disjob.registry.discovery;

import cn.ponfee.disjob.common.concurrent.MultithreadExecutors;
import cn.ponfee.disjob.common.concurrent.NamedThreadFactory;
import cn.ponfee.disjob.common.concurrent.ThreadPoolExecutors;
import cn.ponfee.disjob.core.base.RegistryEventType;
import cn.ponfee.disjob.core.base.Server;
import cn.ponfee.disjob.registry.ServerRole;
import com.google.common.collect.ImmutableList;
import org.apache.commons.collections4.CollectionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.client.RestTemplate;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.SynchronousQueue;

/**
 * Server discovery.
 *
 * @author Ponfee
 */
public abstract class ServerDiscovery {

    protected final Logger log = LoggerFactory.getLogger(getClass());

    public abstract void refreshServers(List servers);

    public abstract void updateServers(RegistryEventType eventType, D server);

    public abstract List getServers(String group);

    public abstract boolean hasServers();

    public abstract boolean isAlive(D server);

    public final void notifyServers(RegistryEventType eventType, R rServer) {
        List servers = getServers();
        if (CollectionUtils.isEmpty(servers)) {
            return;
        }
        int size = servers.size();
        if (size == 1) {
            notifyServer(servers.get(0), eventType, rServer);
            return;
        }
        ExecutorService threadPool = ThreadPoolExecutors.builder()
            .corePoolSize(1)
            .maximumPoolSize(Math.min(size - 1, 100))
            .workQueue(new SynchronousQueue<>())
            .keepAliveTimeSeconds(60)
            .threadFactory(NamedThreadFactory.builder().prefix("notify_server").uncaughtExceptionHandler(log).build())
            .build();
        MultithreadExecutors.run(servers, dServer -> notifyServer(dServer, eventType, rServer), threadPool);
        threadPool.shutdown();
    }

    // ----------------------------------------------------------------default package methods

    abstract List getServers();

    abstract void notifyServer(D dServer, RegistryEventType eventType, R rServer);

    /**
     * Returns sorted ImmutableList
     *
     * @param servers the server list
     * @return sorted ImmutableList
     */
    final ImmutableList toSortedImmutableList(List servers) {
        if (CollectionUtils.isEmpty(servers)) {
            return ImmutableList.of();
        }
        return servers.stream().sorted().collect(ImmutableList.toImmutableList());
    }

    final ImmutableList mergeServers(ImmutableList servers, RegistryEventType eventType, D server) {
        List list;
        if (eventType.isRegister()) {
            list = new ArrayList<>(servers.size() + 1);
            list.addAll(servers);
            list.add(server);
        } else {
            list = new ArrayList<>(servers.size());
            servers.stream().filter(e -> !e.equals(server)).forEach(list::add);
        }
        return toSortedImmutableList(list);
    }

    @SuppressWarnings("unchecked")
    public static  ServerDiscovery of(ServerRole discoveryRole,
                                                                                RestTemplate restTemplate) {
        switch (discoveryRole) {
            case WORKER:
                return (ServerDiscovery) new WorkerDiscovery(restTemplate);
            case SUPERVISOR:
                return (ServerDiscovery) new SupervisorDiscovery(restTemplate);
            default:
                throw new UnsupportedOperationException("Unsupported server discovery role '" + discoveryRole + "'");
        }
    }

}