org.apache.kafka.connect.runtime.Herder 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.connect.runtime;
import org.apache.kafka.connect.runtime.rest.entities.ConnectorInfo;
import org.apache.kafka.connect.runtime.rest.entities.TaskInfo;
import org.apache.kafka.connect.util.Callback;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
/**
*
* The herder interface tracks and manages workers and connectors. It is the main interface for external components
* to make changes to the state of the cluster. For example, in distributed mode, an implementation of this class
* knows how to accept a connector configuration, may need to route it to the current leader worker for the cluster so
* the config can be written to persistent storage, and then ensures the new connector is correctly instantiated on one
* of the workers.
*
*
* This class must implement all the actions that can be taken on the cluster (add/remove connectors, pause/resume tasks,
* get state of connectors and tasks, etc). The non-Java interfaces to the cluster (REST API and CLI) are very simple
* wrappers of the functionality provided by this interface.
*
*
* In standalone mode, this implementation of this class will be trivial because no coordination is needed. In that case,
* the implementation will mainly be delegating tasks directly to other components. For example, when creating a new
* connector in standalone mode, there is no need to persist the config and the connector and its tasks must run in the
* same process, so the standalone herder implementation can immediately instantiate and start the connector and its
* tasks.
*
*/
public interface Herder {
void start();
void stop();
/**
* Get a list of connectors currently running in this cluster. This is a full list of connectors in the cluster gathered
* from the current configuration. However, note
*
* @returns A list of connector names
* @throws org.apache.kafka.connect.runtime.distributed.NotLeaderException if this node can not resolve the request
* (e.g., because it has not joined the cluster or does not have configs in sync with the group) and it is
* also not the leader
* @throws ConnectException if this node is the leader, but still cannot resolve the
* request (e.g., it is not in sync with other worker's config state)
*/
void connectors(Callback> callback);
/**
* Get the definition and status of a connector.
*/
void connectorInfo(String connName, Callback callback);
/**
* Get the configuration for a connector.
* @param connName name of the connector
* @param callback callback to invoke with the configuration
*/
void connectorConfig(String connName, Callback> callback);
/**
* Set the configuration for a connector. This supports creation, update, and deletion.
* @param connName name of the connector
* @param config the connectors configuration, or null if deleting the connector
* @param allowReplace if true, allow overwriting previous configs; if false, throw AlreadyExistsException if a connector
* with the same name already exists
* @param callback callback to invoke when the configuration has been written
*/
void putConnectorConfig(String connName, Map config, boolean allowReplace, Callback> callback);
/**
* Requests reconfiguration of the task. This should only be triggered by
* {@link HerderConnectorContext}.
*
* @param connName name of the connector that should be reconfigured
*/
void requestTaskReconfiguration(String connName);
/**
* Get the configurations for the current set of tasks of a connector.
* @param connName connector to update
* @param callback callback to invoke upon completion
*/
void taskConfigs(String connName, Callback> callback);
/**
* Set the configurations for the tasks of a connector. This should always include all tasks in the connector; if
* there are existing configurations and fewer are provided, this will reduce the number of tasks, and if more are
* provided it will increase the number of tasks.
* @param connName connector to update
* @param configs list of configurations
* @param callback callback to invoke upon completion
*/
void putTaskConfigs(String connName, List> configs, Callback callback);
class Created {
private final boolean created;
private final T result;
public Created(boolean created, T result) {
this.created = created;
this.result = result;
}
public boolean created() {
return created;
}
public T result() {
return result;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Created created1 = (Created) o;
return Objects.equals(created, created1.created) &&
Objects.equals(result, created1.result);
}
@Override
public int hashCode() {
return Objects.hash(created, result);
}
}
}