connect/file/src/main/java/org/apache/kafka/connect/file/FileStreamSourceConnector.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.connect.file;

import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.common.config.ConfigDef.Importance;
import org.apache.kafka.common.config.ConfigDef.Type;
import org.apache.kafka.common.utils.AppInfoParser;
import org.apache.kafka.connect.connector.Task;
import org.apache.kafka.connect.errors.ConnectException;
import org.apache.kafka.connect.source.SourceConnector;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Very simple connector that works with the console. This connector supports both source and
 * sink modes via its 'mode' setting.
 */
public class FileStreamSourceConnector extends SourceConnector {
    public static final String TOPIC_CONFIG = "topic";
    public static final String FILE_CONFIG = "file";

    private static final ConfigDef CONFIG_DEF = new ConfigDef()
        .define(FILE_CONFIG, Type.STRING, Importance.HIGH, "Source filename.")
        .define(TOPIC_CONFIG, Type.STRING, Importance.HIGH, "The topic to publish data to");

    private String filename;
    private String topic;

    @Override
    public String version() {
        return AppInfoParser.getVersion();
    }

    @Override
    public void start(Map<String, String> props) {
        filename = props.get(FILE_CONFIG);
        topic = props.get(TOPIC_CONFIG);
        if (topic == null || topic.isEmpty())
            throw new ConnectException("FileStreamSourceConnector configuration must include 'topic' setting");
        if (topic.contains(","))
            throw new ConnectException("FileStreamSourceConnector should only have a single topic when used as a source.");
    }

    @Override
    public Class<? extends Task> taskClass() {
        return FileStreamSourceTask.class;
    }

    @Override
    public List<Map<String, String>> taskConfigs(int maxTasks) {
        ArrayList<Map<String, String>> configs = new ArrayList<>();
        // Only one input stream makes sense.
        Map<String, String> config = new HashMap<>();
        if (filename != null)
            config.put(FILE_CONFIG, filename);
        config.put(TOPIC_CONFIG, topic);
        configs.add(config);
        return configs;
    }

    @Override
    public void stop() {
        // Nothing to do since FileStreamSourceConnector has no background monitoring.
    }

    @Override
    public ConfigDef config() {
        return CONFIG_DEF;
    }
}