org.apache.kafka.clients.MetadataUpdater Maven / Gradle / Ivy
/*
* 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 org.apache.kafka.common.KafkaException;
import org.apache.kafka.common.Node;
import org.apache.kafka.common.errors.AuthenticationException;
import org.apache.kafka.common.errors.UnsupportedVersionException;
import org.apache.kafka.common.requests.MetadataResponse;
import org.apache.kafka.common.requests.RequestHeader;
import java.io.Closeable;
import java.util.List;
import java.util.Optional;
/**
* The interface used by `NetworkClient` to request cluster metadata info to be updated and to retrieve the cluster nodes
* from such metadata. This is an internal class.
*
* This class is not thread-safe!
*/
public interface MetadataUpdater extends Closeable {
/**
* Gets the current cluster info without blocking.
*/
List fetchNodes();
/**
* Returns true if an update to the cluster metadata info is due.
*/
boolean isUpdateDue(long now);
/**
* Starts a cluster metadata update if needed and possible. Returns the time until the metadata update (which would
* be 0 if an update has been started as a result of this call).
*
* If the implementation relies on `NetworkClient` to send requests, `handleSuccessfulResponse` will be
* invoked after the metadata response is received.
*
* The semantics of `needed` and `possible` are implementation-dependent and may take into account a number of
* factors like node availability, how long since the last metadata update, etc.
*/
long maybeUpdate(long now);
/**
* Handle a server disconnect.
*
* This provides a mechanism for the `MetadataUpdater` implementation to use the NetworkClient instance for its own
* requests with special handling for disconnections of such requests.
*
* @param now Current time in milliseconds
* @param nodeId The id of the node that disconnected
* @param maybeAuthException Optional authentication error
*/
void handleServerDisconnect(long now, String nodeId, Optional maybeAuthException);
/**
* Handle a metadata request failure.
*
* @param now Current time in milliseconds
* @param maybeFatalException Optional fatal error (e.g. {@link UnsupportedVersionException})
*/
void handleFailedRequest(long now, Optional maybeFatalException);
/**
* Handle responses for metadata requests.
*
* This provides a mechanism for the `MetadataUpdater` implementation to use the NetworkClient instance for its own
* requests with special handling for completed receives of such requests.
*/
void handleSuccessfulResponse(RequestHeader requestHeader, long now, MetadataResponse metadataResponse);
/**
* Close this updater.
*/
@Override
void close();
}