jolshan commented on code in PR #15685: URL: https://github.com/apache/kafka/pull/15685#discussion_r1603378178
########## server-common/src/main/java/org/apache/kafka/server/common/FeatureVersion.java: ########## @@ -0,0 +1,137 @@ +/* + * 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.server.common; + +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; +import java.util.Map; +import java.util.Optional; +import java.util.stream.Collectors; + +/** + * This is enum for the various features implemented for Kafka clusters. + * KIP-584: Versioning Scheme for Features introduced the idea of various features, but only added one feature -- MetadataVersion. + * KIP-1022: Formatting and Updating Features allowed for more features to be added. In order to set and update features, + * they need to be specified via the StorageTool or FeatureCommand tools. + * <br> + * Having a unified enum for the features that will use a shared type in the API used to set and update them + * makes it easier to process these features. + */ +public enum FeatureVersion { + + /** + * Features defined. If a feature is included in this list, and marked to be used in production they will also be specified when + * formatting a cluster via the StorageTool. MetadataVersion is handled separately, so it is not included here. + * + * See {@link TestFeatureVersion} as an example. See {@link FeatureVersionUtils.FeatureVersionImpl} when implementing a new feature. + */ + TEST_VERSION("test.feature.version", TestFeatureVersion.values(), TestFeatureVersion::fromFeatureLevel, false); + + public static final FeatureVersion[] FEATURES; + public static final List<FeatureVersion> PRODUCTION_FEATURES; + private final String name; + private final FeatureVersionUtils.FeatureVersionImpl[] features; + private final FeatureVersionUtils.CreateMethod createFeatureVersionMethod; + private final boolean usedInProduction; + + FeatureVersion(String name, + FeatureVersionUtils.FeatureVersionImpl[] features, + FeatureVersionUtils.CreateMethod createMethod, + boolean usedInProduction) { + this.name = name; + this.features = features; + this.createFeatureVersionMethod = createMethod; + this.usedInProduction = usedInProduction; + } + + static { + FeatureVersion[] enumValues = FeatureVersion.values(); + FEATURES = Arrays.copyOf(enumValues, enumValues.length); + + PRODUCTION_FEATURES = Arrays.stream(FEATURES).filter(feature -> + feature.usedInProduction).collect(Collectors.toList()); + } + + public String featureName() { + return name; + } + + /** + * Creates a FeatureVersion from a given name and level with the correct feature object underneath. + * + * @param level the level of the feature + * @returns the FeatureVersionUtils.FeatureVersionImpl for the feature the enum is based on. + * @throws IllegalArgumentException if the feature name is not valid (not implemented for this method) + */ + public FeatureVersionUtils.FeatureVersionImpl fromFeatureLevel(short level) { + return createFeatureVersionMethod.fromFeatureLevel(level); + } + + /** + * A method to validate the feature can be set. If a given feature relies on another feature, the dependencies should be + * captured in {@link FeatureVersionUtils.FeatureVersionImpl#dependencies()} + * <p> + * For example, say feature X level x relies on feature Y level y: + * if feature X >= x then throw an error if feature Y < y. + * + * All feature levels above 0 require metadata.version=4 (IBP_3_3_IV0) in order to write the feature records to the cluster. + * + * @param feature the feature we are validating + * @param metadataVersion the metadata version we have (or want to set) + * @param features the feature versions (besides MetadataVersion) we have (or want to set) + * @throws IllegalArgumentException if the feature is not valid + */ + public static void validateVersion(FeatureVersionUtils.FeatureVersionImpl feature, MetadataVersion metadataVersion, Map<String, Short> features) { + if (feature.featureLevel() >= 1 && metadataVersion.isLessThan(MetadataVersion.IBP_3_3_IV0)) + throw new IllegalArgumentException(feature.featureName() + " could not be set to " + feature.featureLevel() + + " because it depends on metadata.version=14 (" + MetadataVersion.IBP_3_3_IV0 + ")"); + + for (Map.Entry<String, Short> dependency: feature.dependencies().entrySet()) { + Short featureLevel = features.get(dependency.getKey()); + + if (featureLevel == null || featureLevel < dependency.getValue()) { + throw new IllegalArgumentException(feature.featureName() + " could not be set to " + feature.featureLevel() + + " because it depends on " + dependency.getKey() + " level " + dependency.getValue()); + } + } + } + + /** + * A method to return the default version level of a feature. If metadataVersionOpt is not empty, the default is based on + * the metadataVersion. If not, use the latest production version for the given feature. + * + * Every time a new feature is added, it should create a mapping from metadata version to feature version + * with {@link FeatureVersionUtils.FeatureVersionImpl#metadataVersionMapping()} + * + * @param metadataVersionOpt the metadata version we want to use to set the default, or None if the latest production version is desired + * @return the default version level for the feature and potential metadata version + */ + public short defaultValue(Optional<MetadataVersion> metadataVersionOpt) { + MetadataVersion mv = metadataVersionOpt.orElse(MetadataVersion.LATEST_PRODUCTION); Review Comment: Semantically they didn't pass any value, but sure, I can move this logic to be right before I call the method. -- This is an automated message from the Apache Git Service. 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