tzulitai commented on a change in pull request #8861: [FLINK-12963][state-processor-api] Add savepoint writer for bootstrapping new savepoints URL: https://github.com/apache/flink/pull/8861#discussion_r300132825
########## File path: flink-libraries/flink-state-processing-api/src/main/java/org/apache/flink/state/api/WritableSavepoint.java ########## @@ -0,0 +1,129 @@ +/* + * 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.flink.state.api; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.api.java.DataSet; +import org.apache.flink.core.fs.Path; +import org.apache.flink.runtime.checkpoint.OperatorState; +import org.apache.flink.runtime.state.StateBackend; +import org.apache.flink.state.api.output.MergeOperatorStates; +import org.apache.flink.state.api.output.SavepointOutputFormat; +import org.apache.flink.state.api.runtime.metadata.ModifiableSavepointMetadata; +import org.apache.flink.util.Preconditions; + +import java.util.List; +import java.util.stream.Collectors; + +/** + * Any savepoint that can be written to from a batch context. + * @param <F> The implementation type. + */ +@PublicEvolving +@SuppressWarnings("WeakerAccess") +public abstract class WritableSavepoint<F extends WritableSavepoint> { + + protected final ModifiableSavepointMetadata metadata; + + protected final StateBackend stateBackend; + + WritableSavepoint(ModifiableSavepointMetadata metadata, StateBackend stateBackend) { + Preconditions.checkNotNull(metadata, "The savepoint metadata must not be null"); + Preconditions.checkNotNull(stateBackend, "The state backend must not be null"); + this.metadata = metadata; + this.stateBackend = stateBackend; + } + + /** + * Drop an existing operator from the savepoint. + * @param uid The uid of the operator. + * @return A modified savepoint. + */ + @SuppressWarnings("unchecked") + public F removeOperator(String uid) { + metadata.removeOperator(uid); + return (F) this; + } + + /** + * Adds a new operator to the savepoint. + * @param uid The uid of the operator. + * @param transformation The operator to be included. + * @return The modified savepoint. + */ + @SuppressWarnings("unchecked") + public <T> F withOperator(String uid, BootstrapTransformation<T> transformation) { + metadata.addOperator(uid, transformation); + return (F) this; + } + + /** + * Write out a new or updated savepoint. + * @param path The path to where the savepoint should be written. + */ + public final void write(String path) { + final Path savepointPath = new Path(path); + + DataSet<OperatorState> newOperatorStates = getOperatorStates(savepointPath); + + List<OperatorState> existingOperators = getExistingOperatorStates(); + + DataSet<OperatorState> finalOperatorStates = unionOperatorStates(newOperatorStates, existingOperators); + + finalOperatorStates + .reduceGroup(new MergeOperatorStates(metadata)) + .name("reduce(OperatorState)") + .output(new SavepointOutputFormat(savepointPath)) + .name(path); + } + + private DataSet<OperatorState> unionOperatorStates(DataSet<OperatorState> newOperatorStates, List<OperatorState> existingOperators) { + DataSet<OperatorState> finalOperatorStates; + if (existingOperators.isEmpty()) { + finalOperatorStates = newOperatorStates; + } else { + DataSet<OperatorState> wrappedCollection = newOperatorStates + .getExecutionEnvironment() + .fromCollection(existingOperators); + + finalOperatorStates = newOperatorStates.union(wrappedCollection); + } + return finalOperatorStates; + } + + private List<OperatorState> getExistingOperatorStates() { Review comment: I think this method as well as `getOperatorStates(Path)` should be refactored into `ModifiableSavepointMetadata`. The concern of filtering out the operator state index to return only the existing / new operator states can be encapsulated there. ---------------------------------------------------------------- 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: [email protected] With regards, Apache Git Services
