ZookeeperClientFactoryImpl.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * 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 com.yahoo.pulsar.zookeeper;

import static com.google.common.base.Preconditions.checkArgument;

import java.io.IOException;
import java.nio.charset.Charset;
import java.util.concurrent.CompletableFuture;

import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher.Event;
import org.apache.zookeeper.ZooKeeper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ZookeeperClientFactoryImpl implements ZooKeeperClientFactory {
    public static final Charset ENCODING_SCHEME = Charset.forName("UTF-8");

    @Override
    public CompletableFuture<ZooKeeper> create(String serverList, SessionType sessionType, int zkSessionTimeoutMillis) {
        // Create a normal ZK client
        boolean canBeReadOnly = sessionType == SessionType.AllowReadOnly;

        CompletableFuture<ZooKeeper> future = new CompletableFuture<>();
        try {
            CompletableFuture<Void> internalFuture = new CompletableFuture<>();

            ZooKeeper zk = new ZooKeeper(serverList, zkSessionTimeoutMillis, event -> {
                if (event.getType() == Event.EventType.None) {
                    switch (event.getState()) {

                    case ConnectedReadOnly:
                        checkArgument(canBeReadOnly);
                        // Fall through
                    case SyncConnected:
                        // ZK session is ready to use
                        internalFuture.complete(null);
                        break;

                    case Expired:
                        internalFuture
                                .completeExceptionally(KeeperException.create(KeeperException.Code.SESSIONEXPIRED));
                        break;

                    default:
                        log.warn("Unexpected ZK event received: {}", event);
                        break;
                    }
                }
            }, canBeReadOnly);

            internalFuture.thenRun(() -> {
                log.info("ZooKeeper session established: {}", zk);
                future.complete(zk);
            }).exceptionally((exception) -> {
                log.error("Failed to establish ZooKeeper session: {}", exception.getMessage());
                future.completeExceptionally(exception);
                return null;
            });

        } catch (IOException e) {
            future.completeExceptionally(e);
        }

        return future;
    }

    private static final Logger log = LoggerFactory.getLogger(ZookeeperClientFactoryImpl.class);
}