¡¾kafka¡¿Ê¹ÓÃKafka Connect API´´½¨Apache KafkaÁ¬½ÓÆ÷µÄ4¸ö²½Öè

name=local-file-source
connector.class=FileStreamSource
tasks.max=1
file=test.txt
topic=connect-test

name=local-file-sink
connector.class=FileStreamSink
tasks.max=1
file=test.sink.txt
topics=connect-test

bootstrap.servers=localhost:9092
key.converter=org.apache.kafka.connect.json.JsonConverter
value.converter=org.apache.kafka.connect.json.JsonConverter
key.converter.schemas.enable=true
value.converter.schemas.enable=trueinternal.key.converter=org.apache.kafka.connect.json.JsonConverter
internal.value.converter=org.apache.kafka.connect.json.JsonConverter
internal.key.converter.schemas.enable=false
internal.value.converter.schemas.enable=false
offset.storage.file.filename=/tmp/connect.offsets
offset.flush.interval.ms=10000

Æô¶¯Kafka Broker
ÏÈÔËÐÐzookeeper
[root@localhost kafka_2.11-0.11.0.0]# ./bin/zookeeper-server-start.sh ./config/zookeeper.properties &
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[root@localhost kafka_2.11-0.11.0.0]# ./bin/kafka-server-start.sh ./config/server.properties &

[root@localhost kafka_2.11-0.11.0.0]# ./bin/connect-standalone.sh config/connect-standalone.properties config/connect-file-source.properties config/connect-file-sink.properties

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./kafka-console-consumer.sh --bootstrap-server 192.168.137.121:9092 --topic connect-test  --from-beginning

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[root@Server4 kafka_2.12-0.11.0.0]# echo 'firest line' >> test.txt
[root@Server4 kafka_2.12-0.11.0.0]# echo 'second line' >> test.txt

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{"schema":{"type":"string","optional":false},"payload":"firest line"}
{"schema":{"type":"string","optional":false},"payload":"second line"}

²é¿´test.sink.txt
[root@Server4 kafka_2.12-0.11.0.0]# cat test.sink.txt 
firest line
second line

http://kafka.apache.org/documentation/#connect

https://docs.confluent.io/current/connect/index.html

https://www.confluent.io/blog/create-dynamic-kafka-connect-source-connectors/

https://github.com/apache/kafka/tree/trunk/connect

http://www.itrensheng.com/archives/apache-kafka-kafka-connectfileconnector

https://github.com/apache/kafka/tree/trunk/connect/file/src/main/java/org/apache/kafka/connect/file

// ¿ª·¢×Ô¼ºµÄconnect
https://www.jdon.com/54527
https://www.cnblogs.com/laoqing/p/11927958.html
https://www.orchome.com/345
// debezium ¿ªÔ´ÊµÏֱȽϺõÄ
https://github.com/debezium/debezium 

 <!-- https://mvnrepository.com/artifact/org.apache.kafka/connect-api -->
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>connect-api</artifactId>
            <version>2.6.0</version>
        </dependency>

/*
 * 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.connector;

import java.util.Map;

/**
 * <p>
 * Tasks contain the code that actually copies data to/from another system. They receive
 * a configuration from their parent Connector, assigning them a fraction of a Kafka Connect job's work.
 * The Kafka Connect framework then pushes/pulls data from the Task. The Task must also be able to
 * respond to reconfiguration requests.
 * </p>
 * <p>
 * Task only contains the minimal shared functionality between
 * {@link org.apache.kafka.connect.source.SourceTask} and
 * {@link org.apache.kafka.connect.sink.SinkTask}.
 * </p>
 */
public interface Task {
    /**
     * Get the version of this task. Usually this should be the same as the corresponding {@link Connector} class's version.
     *
     * @return the version, formatted as a String
     */
    String version();

    /**
     * Start the Task
     * @param props initial configuration
     */
    void start(Map<String, String> props);

    /**
     * Stop this task.
     */
    void stop();
}

/*
 * 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.source;

import org.apache.kafka.connect.connector.Task;
import org.apache.kafka.clients.producer.RecordMetadata;

import java.util.List;
import java.util.Map;

/**
 * SourceTask is a Task that pulls records from another system for storage in Kafka.
 */
public abstract class SourceTask implements Task {

    protected SourceTaskContext context;

    /**
     * Initialize this SourceTask with the specified context object.
     */
    public void initialize(SourceTaskContext context) {
        this.context = context;
    }

    /**
     * Start the Task. This should handle any configuration parsing and one-time setup of the task.
     * @param props initial configuration
     */
    @Override
    public abstract void start(Map<String, String> props);

    /**
     * <p>
     * Poll this source task for new records. If no data is currently available, this method
     * should block but return control to the caller regularly (by returning {@code null}) in
     * order for the task to transition to the {@code PAUSED} state if requested to do so.
     * </p>
     * <p>
     * The task will be {@link #stop() stopped} on a separate thread, and when that happens
     * this method is expected to unblock, quickly finish up any remaining processing, and
     * return.
     * </p>
     *
     * @return a list of source records
     */
    public abstract List<SourceRecord> poll() throws InterruptedException;

    /**
     * <p>
     * Commit the offsets, up to the offsets that have been returned by {@link #poll()}. This
     * method should block until the commit is complete.
     * </p>
     * <p>
     * SourceTasks are not required to implement this functionality; Kafka Connect will record offsets
     * automatically. This hook is provided for systems that also need to store offsets internally
     * in their own system.
     * </p>
     */
    public void commit() throws InterruptedException {
        // This space intentionally left blank.
    }

    /**
     * Signal this SourceTask to stop. In SourceTasks, this method only needs to signal to the task that it should stop
     * trying to poll for new data and interrupt any outstanding poll() requests. It is not required that the task has
     * fully stopped. Note that this method necessarily may be invoked from a different thread than {@link #poll()} and
     * {@link #commit()}.
     *
     * For example, if a task uses a {@link java.nio.channels.Selector} to receive data over the network, this method
     * could set a flag that will force {@link #poll()} to exit immediately and invoke
     * {@link java.nio.channels.Selector#wakeup() wakeup()} to interrupt any ongoing requests.
     */
    @Override
    public abstract void stop();

    /**
     * <p>
     * Commit an individual {@link SourceRecord} when the callback from the producer client is received. This method is
     * also called when a record is filtered by a transformation, and thus will never be ACK'd by a broker.
     * </p>
     * <p>
     * This is an alias for {@link #commitRecord(SourceRecord, RecordMetadata)} for backwards compatibility. The default
     * implementation of {@link #commitRecord(SourceRecord, RecordMetadata)} just calls this method. It is not necessary
     * to override both methods.
     * </p>
     * <p>
     * SourceTasks are not required to implement this functionality; Kafka Connect will record offsets
     * automatically. This hook is provided for systems that also need to store offsets internally
     * in their own system.
     * </p>
     *
     * @param record {@link SourceRecord} that was successfully sent via the producer or filtered by a transformation
     * @throws InterruptedException
     * @deprecated Use {@link #commitRecord(SourceRecord, RecordMetadata)} instead.
     */
    @Deprecated
    public void commitRecord(SourceRecord record) throws InterruptedException {
        // This space intentionally left blank.
    }

    /**
     * <p>
     * Commit an individual {@link SourceRecord} when the callback from the producer client is received. This method is
     * also called when a record is filtered by a transformation, and thus will never be ACK'd by a broker. In this case
     * {@code metadata} will be null.
     * </p>
     * <p>
     * SourceTasks are not required to implement this functionality; Kafka Connect will record offsets
     * automatically. This hook is provided for systems that also need to store offsets internally
     * in their own system.
     * </p>
     * <p>
     * The default implementation just calls {@link #commitRecord(SourceRecord)}, which is a nop by default. It is
     * not necessary to implement both methods.
     * </p>
     *
     * @param record {@link SourceRecord} that was successfully sent via the producer or filtered by a transformation
     * @param metadata {@link RecordMetadata} record metadata returned from the broker, or null if the record was filtered
     * @throws InterruptedException
     */
    public void commitRecord(SourceRecord record, RecordMetadata metadata)
            throws InterruptedException {
        // by default, just call other method for backwards compatibility
        commitRecord(record);
    }
}

/*
 * 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.sink;

import org.apache.kafka.clients.consumer.OffsetAndMetadata;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.connect.connector.Task;

import java.util.Collection;
import java.util.Map;

/**
 * SinkTask is a Task that takes records loaded from Kafka and sends them to another system. Each task
 * instance is assigned a set of partitions by the Connect framework and will handle all records received
 * from those partitions. As records are fetched from Kafka, they will be passed to the sink task using the
 * {@link #put(Collection)} API, which should either write them to the downstream system or batch them for
 * later writing. Periodically, Connect will call {@link #flush(Map)} to ensure that batched records are
 * actually pushed to the downstream system..
 *
 * Below we describe the lifecycle of a SinkTask.
 *
 * <ol>
 *     <li><b>Initialization:</b> SinkTasks are first initialized using {@link #initialize(SinkTaskContext)}
 *     to prepare the task's context and {@link #start(Map)} to accept configuration and start any services
 *     needed for processing.</li>
 *     <li><b>Partition Assignment:</b> After initialization, Connect will assign the task a set of partitions
 *     using {@link #open(Collection)}. These partitions are owned exclusively by this task until they
 *     have been closed with {@link #close(Collection)}.</li>
 *     <li><b>Record Processing:</b> Once partitions have been opened for writing, Connect will begin forwarding
 *     records from Kafka using the {@link #put(Collection)} API. Periodically, Connect will ask the task
 *     to flush records using {@link #flush(Map)} as described above.</li>
 *     <li><b>Partition Rebalancing:</b> Occasionally, Connect will need to change the assignment of this task.
 *     When this happens, the currently assigned partitions will be closed with {@link #close(Collection)} and
 *     the new assignment will be opened using {@link #open(Collection)}.</li>
 *     <li><b>Shutdown:</b> When the task needs to be shutdown, Connect will close active partitions (if there
 *     are any) and stop the task using {@link #stop()}</li>
  * </ol>
 *
 */
public abstract class SinkTask implements Task {

    /**
     * <p>
     * The configuration key that provides the list of topics that are inputs for this
     * SinkTask.
     * </p>
     */
    public static final String TOPICS_CONFIG = "topics";

    /**
     * <p>
     * The configuration key that provides a regex specifying which topics to include as inputs
     * for this SinkTask.
     * </p>
     */
    public static final String TOPICS_REGEX_CONFIG = "topics.regex";

    protected SinkTaskContext context;

    /**
     * Initialize the context of this task. Note that the partition assignment will be empty until
     * Connect has opened the partitions for writing with {@link #open(Collection)}.
     * @param context The sink task's context
     */
    public void initialize(SinkTaskContext context) {
        this.context = context;
    }

    /**
     * Start the Task. This should handle any configuration parsing and one-time setup of the task.
     * @param props initial configuration
     */
    @Override
    public abstract void start(Map<String, String> props);

    /**
     * Put the records in the sink. Usually this should send the records to the sink asynchronously
     * and immediately return.
     *
     * If this operation fails, the SinkTask may throw a {@link org.apache.kafka.connect.errors.RetriableException} to
     * indicate that the framework should attempt to retry the same call again. Other exceptions will cause the task to
     * be stopped immediately. {@link SinkTaskContext#timeout(long)} can be used to set the maximum time before the
     * batch will be retried.
     *
     * @param records the set of records to send
     */
    public abstract void put(Collection<SinkRecord> records);

    /**
     * Flush all records that have been {@link #put(Collection)} for the specified topic-partitions.
     *
     * @param currentOffsets the current offset state as of the last call to {@link #put(Collection)}},
     *                       provided for convenience but could also be determined by tracking all offsets included in the {@link SinkRecord}s
     *                       passed to {@link #put}.
     */
    public void flush(Map<TopicPartition, OffsetAndMetadata> currentOffsets) {
    }

    /**
     * Pre-commit hook invoked prior to an offset commit.
     *
     * The default implementation simply invokes {@link #flush(Map)} and is thus able to assume all {@code currentOffsets} are safe to commit.
     *
     * @param currentOffsets the current offset state as of the last call to {@link #put(Collection)}},
     *                       provided for convenience but could also be determined by tracking all offsets included in the {@link SinkRecord}s
     *                       passed to {@link #put}.
     *
     * @return an empty map if Connect-managed offset commit is not desired, otherwise a map of offsets by topic-partition that are safe to commit.
     */
    public Map<TopicPartition, OffsetAndMetadata> preCommit(Map<TopicPartition, OffsetAndMetadata> currentOffsets) {
        flush(currentOffsets);
        return currentOffsets;
    }

    /**
     * The SinkTask use this method to create writers for newly assigned partitions in case of partition
     * rebalance. This method will be called after partition re-assignment completes and before the SinkTask starts
     * fetching data. Note that any errors raised from this method will cause the task to stop.
     * @param partitions The list of partitions that are now assigned to the task (may include
     *                   partitions previously assigned to the task)
     */
    public void open(Collection<TopicPartition> partitions) {
        this.onPartitionsAssigned(partitions);
    }

    /**
     * @deprecated Use {@link #open(Collection)} for partition initialization.
     */
    @Deprecated
    public void onPartitionsAssigned(Collection<TopicPartition> partitions) {
    }

    /**
     * The SinkTask use this method to close writers for partitions that are no
     * longer assigned to the SinkTask. This method will be called before a rebalance operation starts
     * and after the SinkTask stops fetching data. After being closed, Connect will not write
     * any records to the task until a new set of partitions has been opened. Note that any errors raised
     * from this method will cause the task to stop.
     * @param partitions The list of partitions that should be closed
     */
    public void close(Collection<TopicPartition> partitions) {
        this.onPartitionsRevoked(partitions);
    }

    /**
     * @deprecated Use {@link #close(Collection)} instead for partition cleanup.
     */
    @Deprecated
    public void onPartitionsRevoked(Collection<TopicPartition> partitions) {
    }

    /**
     * Perform any cleanup to stop this task. In SinkTasks, this method is invoked only once outstanding calls to other
     * methods have completed (e.g., {@link #put(Collection)} has returned) and a final {@link #flush(Map)} and offset
     * commit has completed. Implementations of this method should only need to perform final cleanup operations, such
     * as closing network connections to the sink system.
     */
    @Override
    public abstract void stop();
}

/*
 * 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.connector;

import org.apache.kafka.common.config.Config;
import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.common.config.ConfigValue;
import org.apache.kafka.connect.errors.ConnectException;
import org.apache.kafka.connect.components.Versioned;

import java.util.List;
import java.util.Map;

/**
 * <p>
 * Connectors manage integration of Kafka Connect with another system, either as an input that ingests
 * data into Kafka or an output that passes data to an external system. Implementations should
 * not use this class directly; they should inherit from {@link org.apache.kafka.connect.source.SourceConnector SourceConnector}
 * or {@link org.apache.kafka.connect.sink.SinkConnector SinkConnector}.
 * </p>
 * <p>
 * Connectors have two primary tasks. First, given some configuration, they are responsible for
 * creating configurations for a set of {@link Task}s that split up the data processing. For
 * example, a database Connector might create Tasks by dividing the set of tables evenly among
 * tasks. Second, they are responsible for monitoring inputs for changes that require
 * reconfiguration and notifying the Kafka Connect runtime via the {@link ConnectorContext}. Continuing the
 * previous example, the connector might periodically check for new tables and notify Kafka Connect of
 * additions and deletions. Kafka Connect will then request new configurations and update the running
 * Tasks.
 * </p>
 */
public abstract class Connector implements Versioned {

    protected ConnectorContext context;


    /**
     * Initialize this connector, using the provided ConnectorContext to notify the runtime of
     * input configuration changes.
     * @param ctx context object used to interact with the Kafka Connect runtime
     */
    public void initialize(ConnectorContext ctx) {
        context = ctx;
    }

    /**
     * <p>
     * Initialize this connector, using the provided ConnectorContext to notify the runtime of
     * input configuration changes and using the provided set of Task configurations.
     * This version is only used to recover from failures.
     * </p>
     * <p>
     * The default implementation ignores the provided Task configurations. During recovery, Kafka Connect will request
     * an updated set of configurations and update the running Tasks appropriately. However, Connectors should
     * implement special handling of this case if it will avoid unnecessary changes to running Tasks.
     * </p>
     *
     * @param ctx context object used to interact with the Kafka Connect runtime
     * @param taskConfigs existing task configurations, which may be used when generating new task configs to avoid
     *                    churn in partition to task assignments
     */
    public void initialize(ConnectorContext ctx, List<Map<String, String>> taskConfigs) {
        context = ctx;
        // Ignore taskConfigs. May result in more churn of tasks during recovery if updated configs
        // are very different, but reduces the difficulty of implementing a Connector
    }

    /**
     * Returns the context object used to interact with the Kafka Connect runtime.
     *
     * @return the context for this Connector.
     */
    protected ConnectorContext context() {
        return context;
    }

    /**
     * Start this Connector. This method will only be called on a clean Connector, i.e. it has
     * either just been instantiated and initialized or {@link #stop()} has been invoked.
     *
     * @param props configuration settings
     */
    public abstract void start(Map<String, String> props);

    /**
     * Reconfigure this Connector. Most implementations will not override this, using the default
     * implementation that calls {@link #stop()} followed by {@link #start(Map)}.
     * Implementations only need to override this if they want to handle this process more
     * efficiently, e.g. without shutting down network connections to the external system.
     *
     * @param props new configuration settings
     */
    public void reconfigure(Map<String, String> props) {
        stop();
        start(props);
    }

    /**
     * Returns the Task implementation for this Connector.
     */
    public abstract Class<? extends Task> taskClass();

    /**
     * Returns a set of configurations for Tasks based on the current configuration,
     * producing at most count configurations.
     *
     * @param maxTasks maximum number of configurations to generate
     * @return configurations for Tasks
     */
    public abstract List<Map<String, String>> taskConfigs(int maxTasks);

    /**
     * Stop this connector.
     */
    public abstract void stop();

    /**
     * Validate the connector configuration values against configuration definitions.
     * @param connectorConfigs the provided configuration values
     * @return List of Config, each Config contains the updated configuration information given
     * the current configuration values.
     */
    public Config validate(Map<String, String> connectorConfigs) {
        ConfigDef configDef = config();
        if (null == configDef) {
            throw new ConnectException(
                String.format("%s.config() must return a ConfigDef that is not null.", this.getClass().getName())
            );
        }
        List<ConfigValue> configValues = configDef.validate(connectorConfigs);
        return new Config(configValues);
    }

    /**
     * Define the configuration for the connector.
     * @return The ConfigDef for this connector; may not be null.
     */
    public abstract ConfigDef config();
}