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package org.apache.kafka.server.policy;
/**
* An interface for enforcing a policy on create topics requests.
*
* Common use cases are requiring that the replication factor, min.insync.replicas and/or retention settings for a
* topic are within an allowable range.
*
* If <code>create.topic.policy.class.name</code> is defined, Kafka will create an instance of the specified class
* using the default constructor and will then pass the broker configs to its <code>configure()</code> method. During
* broker shutdown, the <code>close()</code> method will be invoked so that resources can be released (if necessary).
*/
public interface CreateTopicPolicy extends Configurable, AutoCloseable {
/**
* Class containing the create request parameters.
*/
class RequestMetadata {
private final String topic;
private final Integer numPartitions;
private final Short replicationFactor;
private final Map<Integer, List<Integer>> replicasAssignments;
private final Map<String, String> configs;
/**
* Create an instance of this class with the provided parameters.
*
* This constructor is public to make testing of <code>CreateTopicPolicy</code> implementations easier.
*
* @param topic the name of the topic to created.
* @param numPartitions the number of partitions to create or null if replicasAssignments is set.
* @param replicationFactor the replication factor for the topic or null if replicaAssignments is set.
* @param replicasAssignments replica assignments or null if numPartitions and replicationFactor is set. The
* assignment is a map from partition id to replica (broker) ids.
* @param configs topic configs for the topic to be created, not including broker defaults. Broker configs are
* passed via the {@code configure()} method of the policy implementation.
*/
public RequestMetadata(String topic, Integer numPartitions, Short replicationFactor,
Map<Integer, List<Integer>> replicasAssignments, Map<String, String> configs) {
this.topic = topic;
this.numPartitions = numPartitions;
this.replicationFactor = replicationFactor;
this.replicasAssignments = replicasAssignments == null ? null : Collections.unmodifiableMap(replicasAssignments);
this.configs = Collections.unmodifiableMap(configs);
}
/**
* Return the name of the topic to create.
*/
public String topic() {
return topic;
}
/**
* Return the number of partitions to create or null if replicaAssignments is not null.
*/
public Integer numPartitions() {
return numPartitions;
}
/**
* Return the number of replicas to create or null if replicaAssignments is not null.
*/
public Short replicationFactor() {
return replicationFactor;
}
/**
* Return a map from partition id to replica (broker) ids or null if numPartitions and replicationFactor are
* set instead.
*/
public Map<Integer, List<Integer>> replicasAssignments() {
return replicasAssignments;
}
/**
* Return topic configs in the request, not including broker defaults. Broker configs are passed via
* the {@code configure()} method of the policy implementation.
*/
public Map<String, String> configs() {
return configs;
}
@Override
public String toString() {
return "RequestMetadata(topic=" + topic +
", numPartitions=" + numPartitions +
", replicationFactor=" + replicationFactor +
", replicasAssignments=" + replicasAssignments +
", configs=" + configs + ")";
}
}
/**
* Validate the request parameters and throw a <code>PolicyViolationException</code> with a suitable error
* message if the create request parameters for the provided topic do not satisfy this policy.
*
* Clients will receive the POLICY_VIOLATION error code along with the exception's message. Note that validation
* failure only affects the relevant topic, other topics in the request will still be processed.
*
* @param requestMetadata the create request parameters for the provided topic.
* @throws PolicyViolationException if the request parameters do not satisfy this policy.
*/
void validate(RequestMetadata requestMetadata) throws PolicyViolationException;
} |
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