org.apache.kafka.connect.source.SourceConnector Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.kafka.connect.source;
import org.apache.kafka.connect.connector.Connector;
import java.util.Map;
/**
* SourceConnectors implement the connector interface to pull data from another system and send
* it to Kafka.
* Kafka Connect may discover implementations of this interface using the Java {@link java.util.ServiceLoader} mechanism.
* To support this, implementations of this interface should also contain a service provider configuration file in
* {@code META-INF/services/org.apache.kafka.connect.source.SourceConnector}.
*/
public abstract class SourceConnector extends Connector {
@Override
protected SourceConnectorContext context() {
return (SourceConnectorContext) context;
}
/**
* Signals whether the connector supports exactly-once semantics with a proposed configuration.
* Connector authors can assume that worker-level exactly-once support is enabled when this method is invoked.
*
*
For backwards compatibility, the default implementation will return {@code null}, but connector authors are
* strongly encouraged to override this method to return a non-null value such as
* {@link ExactlyOnceSupport#SUPPORTED SUPPORTED} or {@link ExactlyOnceSupport#UNSUPPORTED UNSUPPORTED}.
*
*
Similar to {@link #validate(Map) validate}, this method may be called by the runtime before the
* {@link #start(Map) start} method is invoked when the connector will be run with exactly-once support.
*
* @param connectorConfig the configuration that will be used for the connector.
* @return {@link ExactlyOnceSupport#SUPPORTED} if the connector can provide exactly-once support with the given
* configuration, and {@link ExactlyOnceSupport#UNSUPPORTED} if it cannot. If this method is overridden by a
* connector, should not be {@code null}, but if {@code null}, it will be assumed that the connector cannot provide
* exactly-once semantics.
* @since 3.3
*/
public ExactlyOnceSupport exactlyOnceSupport(Map connectorConfig) {
return null;
}
/**
* Signals whether the connector implementation is capable of defining the transaction boundaries for a
* connector with the given configuration. This method is called before {@link #start(Map)}, only when the
* runtime supports exactly-once and the connector configuration includes {@code transaction.boundary=connector}.
*
* This method need not be implemented if the connector implementation does not support defining
* transaction boundaries.
*
* @param connectorConfig the configuration that will be used for the connector
* @return {@link ConnectorTransactionBoundaries#SUPPORTED} if the connector will define its own transaction boundaries,
* or {@link ConnectorTransactionBoundaries#UNSUPPORTED} otherwise; may never be {@code null}. The default implementation
* returns {@link ConnectorTransactionBoundaries#UNSUPPORTED}.
* @since 3.3
* @see TransactionContext
*/
public ConnectorTransactionBoundaries canDefineTransactionBoundaries(Map connectorConfig) {
return ConnectorTransactionBoundaries.UNSUPPORTED;
}
/**
* Invoked when users request to manually alter/reset the offsets for this connector via the Connect worker's REST
* API. Connectors that manage offsets externally can propagate offset changes to their external system in this
* method. Connectors may also validate these offsets to ensure that the source partitions and source offsets are
* in a format that is recognizable to them.
*
* Connectors that neither manage offsets externally nor require custom offset validation need not implement this
* method beyond simply returning {@code true}.
*
* User requests to alter/reset offsets will be handled by the Connect runtime and will be reflected in the offsets
* returned by any {@link org.apache.kafka.connect.storage.OffsetStorageReader OffsetStorageReader instances}
* provided to this connector and its tasks.
*
* Note that altering / resetting offsets is expected to be an idempotent operation and this method should be able
* to handle being called more than once with the same arguments (which could occur if a user retries the request
* due to a failure in writing the new offsets to the offsets store, for example).
*
* Similar to {@link #validate(Map) validate}, this method may be called by the runtime before the
* {@link #start(Map) start} method is invoked.
*
* @param connectorConfig the configuration of the connector
* @param offsets a map from source partition to source offset, containing the offsets that the user has requested
* to alter/reset. For any source partitions whose offsets are being reset instead of altered, their
* corresponding source offset value in the map will be {@code null}. This map may be empty, but
* never null. An empty offsets map could indicate that the offsets were reset previously or that no
* offsets have been committed yet.
* @return whether this method has been overridden by the connector; the default implementation returns
* {@code false}, and all other implementations (that do not unconditionally throw exceptions) should return
* {@code true}
* @throws UnsupportedOperationException if it is impossible to alter/reset the offsets for this connector
* @throws org.apache.kafka.connect.errors.ConnectException if the offsets for this connector cannot be
* reset for any other reason (for example, they have failed custom validation logic specific to this connector)
* @since 3.6
*/
public boolean alterOffsets(Map connectorConfig, Map, Map> offsets) {
return false;
}
}