Package org.apache.kafka.connect.source

Class SourceTask

  • All Implemented Interfaces:
    Task
    public abstract class SourceTask
extends Object
implements Task
    SourceTask is a Task that pulls records from another system for storage in Kafka.

    • Constructor Detail

      • SourceTask

        public SourceTask()

    • Method Detail

      • initialize

        public void initialize​(SourceTaskContext context)
        Initialize this SourceTask with the specified context object.

      • start

        public abstract void start​(Map<String,​String> props)
        Start the Task. This should handle any configuration parsing and one-time setup of the task.
        Specified by:
        start in interface Task
        Parameters:
        props - initial configuration

      • poll

        public abstract List<SourceRecord> poll()
                                 throws InterruptedException

        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 null) in order for the task to transition to the PAUSED state if requested to do so.

        The task will be stopped on a separate thread, and when that happens this method is expected to unblock, quickly finish up any remaining processing, and return.

        Returns:
        a list of source records
        Throws:
        InterruptedException

      • commit

        public void commit()
            throws InterruptedException

        Commit the offsets, up to the offsets that have been returned by poll(). This method should block until the commit is complete.

        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.

        Throws:
        InterruptedException

      • stop

        public abstract void stop()
        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 poll() and commit(). For example, if a task uses a Selector to receive data over the network, this method could set a flag that will force poll() to exit immediately and invoke wakeup() to interrupt any ongoing requests.
        Specified by:
        stop in interface Task

      • commitRecord

        public void commitRecord​(SourceRecord record,
                         RecordMetadata metadata)
                  throws InterruptedException

        Commit an individual 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 metadata will be null.

        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.

        The default implementation just calls commitRecord(SourceRecord), which is a nop by default. It is not necessary to implement both methods.

        Parameters:
        record - SourceRecord that was successfully sent via the producer or filtered by a transformation
        metadata - RecordMetadata record metadata returned from the broker, or null if the record was filtered
        Throws:
        InterruptedException