hachikuji commented on a change in pull request #10275: URL: https://github.com/apache/kafka/pull/10275#discussion_r597064897
########## File path: clients/src/main/java/org/apache/kafka/clients/admin/internals/AdminApiLookupStrategy.java ########## @@ -0,0 +1,94 @@ +/* + * 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.admin.internals; + +import org.apache.kafka.common.requests.AbstractRequest; +import org.apache.kafka.common.requests.AbstractResponse; + +import java.util.Collections; +import java.util.Map; +import java.util.OptionalInt; +import java.util.Set; + +public interface AdminApiLookupStrategy<T> { + + /** + * Define the scope of a given key for lookup. Key lookups are complicated + * by the need to accommodate different batching mechanics. For example, + * a `Metadata` request supports arbitrary batching of topic partitions in + * order to discover partitions leaders. This can be supported by returning + * a single scope object for all keys. + * + * On the other hand, `FindCoordinator` request only supports lookup of a + * single key. This can be supported by returning a different scope object + * for each lookup key. + * + * @param key the lookup key + * + * @return request scope indicating how lookup requests can be batched together + */ + RequestScope lookupScope(T key); + + /** + * Build the lookup request for a set of keys. The grouping of the keys is controlled + * through {@link #lookupScope(Object)}. In other words, each set of keys that map + * to the same request scope object will be sent to this method. + * + * @param keys the set of keys that require lookup + * + * @return a builder for the lookup request + */ + AbstractRequest.Builder<?> buildRequest(Set<T> keys); + + /** + * Callback that is invoked when a lookup request returns successfully. The handler + * should parse the response, check for errors, and return a result indicating + * which keys were mapped to a brokerId successfully and which keys received + * a fatal error (e.g. a topic authorization failure). + * + * Note that keys which receive a retriable error should be left out of the + * result. They will be retried automatically. For example, if the response of + * `FindCoordinator` request indicates an unavailable coordinator, then the key + * should be left out of the result so that the request will be retried. + * + * @param keys the set of keys from the associated request + * @param response the response received from the broker + * + * @return a result indicating which keys mapped successfully to a brokerId and + * which encountered a fatal error + */ + LookupResult<T> handleResponse(Set<T> keys, AbstractResponse response); + + class LookupResult<K> { + public final Map<K, Integer> mappedKeys; + public final Map<K, Throwable> failedKeys; + + public LookupResult( + Map<K, Throwable> failedKeys, + Map<K, Integer> mappedKeys + ) { + this.failedKeys = Collections.unmodifiableMap(failedKeys); + this.mappedKeys = Collections.unmodifiableMap(mappedKeys); + } + } + + interface RequestScope { + default OptionalInt destinationBrokerId() { + return OptionalInt.empty(); + } + } Review comment: Let me think about it. I wasn't entirely happy with this location either. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
