clients/src/main/java/org/apache/kafka/clients/ClientUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.kafka.clients;

import java.io.Closeable;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.kafka.common.config.AbstractConfig;
import org.apache.kafka.common.network.ChannelBuilders;
import org.apache.kafka.common.security.JaasContext;
import org.apache.kafka.common.protocol.SecurityProtocol;
import org.apache.kafka.common.network.ChannelBuilder;
import org.apache.kafka.common.config.ConfigException;
import org.apache.kafka.common.config.SaslConfigs;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.kafka.common.utils.Utils.getHost;
import static org.apache.kafka.common.utils.Utils.getPort;

public class ClientUtils {
    private static final Logger log = LoggerFactory.getLogger(ClientUtils.class);

    public static List<InetSocketAddress> parseAndValidateAddresses(List<String> urls) {
        List<InetSocketAddress> addresses = new ArrayList<>();
        for (String url : urls) {
            if (url != null && !url.isEmpty()) {
                try {
                    String host = getHost(url);
                    Integer port = getPort(url);
                    if (host == null || port == null)
                        throw new ConfigException("Invalid url in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG + ": " + url);

                    InetSocketAddress address = new InetSocketAddress(host, port);

                    if (address.isUnresolved()) {
                        log.warn("Removing server {} from {} as DNS resolution failed for {}", url, CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG, host);
                    } else {
                        addresses.add(address);
                    }
                } catch (IllegalArgumentException e) {
                    throw new ConfigException("Invalid port in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG + ": " + url);
                }
            }
        }
        if (addresses.isEmpty())
            throw new ConfigException("No resolvable bootstrap urls given in " + CommonClientConfigs.BOOTSTRAP_SERVERS_CONFIG);
        return addresses;
    }

    public static void closeQuietly(Closeable c, String name, AtomicReference<Throwable> firstException) {
        if (c != null) {
            try {
                c.close();
            } catch (Throwable t) {
                firstException.compareAndSet(null, t);
                log.error("Failed to close " + name, t);
            }
        }
    }

    /**
     * @param config client configs
     * @return configured ChannelBuilder based on the configs.
     */
    public static ChannelBuilder createChannelBuilder(AbstractConfig config) {
        SecurityProtocol securityProtocol = SecurityProtocol.forName(config.getString(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG));
        if (!SecurityProtocol.nonTestingValues().contains(securityProtocol))
            throw new ConfigException("Invalid SecurityProtocol " + securityProtocol);
        String clientSaslMechanism = config.getString(SaslConfigs.SASL_MECHANISM);
        return ChannelBuilders.clientChannelBuilder(securityProtocol, JaasContext.Type.CLIENT, config, null,
                clientSaslMechanism, true);
    }
}