content: /*
   * 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.policy;
  
  import org.apache.kafka.common.Configurable;
  import org.apache.kafka.common.config.ConfigValue;
  
  import java.util.List;
  
  /**
   * An interface for enforcing a policy on overriding of Kafka client configs via the connector configs.
   * <p>
   * Common use cases are ability to provide principal per connector, <code>sasl.jaas.config</code>
   * and/or enforcing that the producer/consumer configurations for optimizations are within acceptable ranges.
   * <p>Kafka Connect discovers 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.connector.policy.ConnectorClientConfigOverridePolicy}.
   * <p>
   * Implement {@link org.apache.kafka.common.metrics.Monitorable} to enable the policy to register metrics.
   * The following tags are automatically added to all metrics registered: <code>config</code> set to
   * <code>connector.client.config.override.policy</code>, and <code>class</code> set to the
   * ConnectorClientConfigOverridePolicy class name.
   */
  public interface ConnectorClientConfigOverridePolicy extends Configurable, AutoCloseable {
  
  
      /**
       * Workers will invoke this before configuring per-connector Kafka admin, producer, and consumer client instances
       * to validate if all the overridden client configurations are allowed per the policy implementation.
       * This would also be invoked during the validation of connector configs via the REST API.
       * <p>
       * If there are any policy violations, the connector will not be started.
       *
       * @param connectorClientConfigRequest an instance of {@link ConnectorClientConfigRequest} that provides the configs
       *                                     to be overridden and its context; never {@code null}
       * @return list of {@link ConfigValue} instances that describe each client configuration in the request and includes an 
                 {@link ConfigValue#errorMessages() error} if the configuration is not allowed by the policy; never null
       */
      List<ConfigValue> validate(ConnectorClientConfigRequest connectorClientConfigRequest);
  }
  