Zakelly commented on code in PR #22590: URL: https://github.com/apache/flink/pull/22590#discussion_r1223830277
########## flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/filemerging/LogicalFile.java: ########## @@ -0,0 +1,127 @@ +/* + * 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.runtime.checkpoint.filemerging; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.core.fs.Path; +import org.apache.flink.util.StringBasedID; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.UUID; + +import static org.apache.flink.runtime.checkpoint.filemerging.FileMergingSnapshotManager.SubtaskKey; + +/** An abstraction of logical files in file-merging checkpoints. */ +public class LogicalFile { Review Comment: Yes, I added some JavaDocs here. It actually does NOT need to record the offset and length (they are record in the corresponding State Handle), and the logical files are only used to track the usage of the physical by reference counting. However, for semantic integrity, I added the offset and length within `LogicalFile`. ########## flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/filemerging/FileMergingSnapshotManagerBase.java: ########## @@ -0,0 +1,282 @@ +/* + * 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.runtime.checkpoint.filemerging; + +import org.apache.flink.core.fs.EntropyInjector; +import org.apache.flink.core.fs.FSDataOutputStream; +import org.apache.flink.core.fs.FileStatus; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.OutputStreamAndPath; +import org.apache.flink.core.fs.Path; +import org.apache.flink.runtime.checkpoint.filemerging.LogicalFile.LogicalFileId; +import org.apache.flink.runtime.state.CheckpointedStateScope; +import org.apache.flink.util.FlinkRuntimeException; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nonnull; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.util.Map; +import java.util.UUID; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.Executor; + +/** Base implementation of {@link FileMergingSnapshotManager}. */ +public abstract class FileMergingSnapshotManagerBase implements FileMergingSnapshotManager { + + private static final Logger LOG = LoggerFactory.getLogger(FileMergingSnapshotManager.class); + + private final String id; + + protected final Executor ioExecutor; + + // file system and directories + protected FileSystem fs; + protected Path checkpointDir; + protected Path sharedStateDir; + protected Path taskOwnedStateDir; + + protected int writeBufferSize; + private boolean fileSystemInitiated = false; + + protected boolean syncAfterClosingLogicalFile; + + protected PhysicalFile.PhysicalFileDeleter physicalFileDeleter = this::deletePhysicalFile; + + private final Map<SubtaskKey, Path> managedSharedStateDir = new ConcurrentHashMap<>(); + + protected Path managedExclusiveStateDir; + + public FileMergingSnapshotManagerBase(String id, Executor ioExecutor) { + this.id = id; + this.ioExecutor = ioExecutor; + } + + @Override + public void initFileSystem( + FileSystem fileSystem, + Path checkpointBaseDir, + Path sharedStateDir, + Path taskOwnedStateDir) { + if (fileSystemInitiated) { + Preconditions.checkArgument( + checkpointBaseDir.equals(this.checkpointDir), + "The checkpoint base dir is not deterministic across subtasks."); + Preconditions.checkArgument( + sharedStateDir.equals(this.sharedStateDir), + "The shared checkpoint dir is not deterministic across subtasks."); + Preconditions.checkArgument( + taskOwnedStateDir.equals(this.taskOwnedStateDir), + "The task-owned checkpoint dir is not deterministic across subtasks."); + return; + } + this.fs = fileSystem; + this.checkpointDir = Preconditions.checkNotNull(checkpointBaseDir); + this.sharedStateDir = Preconditions.checkNotNull(sharedStateDir); + this.taskOwnedStateDir = Preconditions.checkNotNull(taskOwnedStateDir); + this.fileSystemInitiated = true; + this.syncAfterClosingLogicalFile = shouldSyncAfterClosingLogicalFile(checkpointBaseDir); + // Initialize the managed exclusive path using id as the child path name. + // Currently, we use the task-owned directory to place the merged private state. According + // to the FLIP-306, we later consider move these files to the new introduced + // task-manager-owned directory. + Path managedExclusivePath = new Path(taskOwnedStateDir, id); + createManagedDirectory(managedExclusivePath); + this.managedExclusiveStateDir = managedExclusivePath; + } + + @Override + public void registerSubtaskForSharedStates(SubtaskKey subtaskKey) { + String managedDirName = subtaskKey.getManagedDirName(); + Path managedPath = new Path(sharedStateDir, managedDirName); + if (!managedSharedStateDir.containsKey(subtaskKey)) { + createManagedDirectory(managedPath); + managedSharedStateDir.put(subtaskKey, managedPath); + } + } + + // ------------------------------------------------------------------------ + // logical & physical file + // ------------------------------------------------------------------------ + + protected LogicalFile createLogicalFile( + @Nonnull PhysicalFile physicalFile, @Nonnull SubtaskKey subtaskKey) { + LogicalFileId fileID = LogicalFileId.generateRandomId(); + return new LogicalFile(fileID, physicalFile, subtaskKey); + } + + @Nonnull + protected PhysicalFile createPhysicalFile(SubtaskKey subtaskKey, CheckpointedStateScope scope) + throws IOException { + PhysicalFile result; + Exception latestException = null; + + Path dirPath = getManagedDir(subtaskKey, scope); + + if (dirPath == null) { + throw new IOException( + "Could not get " + + scope + + " path for subtask " + + subtaskKey + + ", the directory may have not been created."); + } + + for (int attempt = 0; attempt < 10; attempt++) { + try { + OutputStreamAndPath streamAndPath = + EntropyInjector.createEntropyAware( + fs, + createPhysicalFilePath(dirPath), + FileSystem.WriteMode.NO_OVERWRITE); + FSDataOutputStream outputStream = streamAndPath.stream(); + Path filePath = streamAndPath.path(); + result = new PhysicalFile(outputStream, filePath, this.physicalFileDeleter, scope); + updateFileCreationMetrics(filePath); + return result; + } catch (Exception e) { + latestException = e; + } + } + + throw new IOException( + "Could not open output stream for state file merging.", latestException); + } + + private void updateFileCreationMetrics(Path path) { + // TODO: FLINK- add io metrics + LOG.debug("Create a new physical file {} for checkpoint file merging.", path); + } + + protected Path createPhysicalFilePath(Path dirPath) { + // this must be called after initFileSystem() is called + // so the checkpoint directories must be not null if we reach here + final String fileName = UUID.randomUUID().toString(); + return new Path(dirPath, fileName); + } + + protected final void deletePhysicalFile(FSDataOutputStream outputStream, Path filePath) { + + if (outputStream != null) { + try { + outputStream.close(); + } catch (IOException e) { + LOG.warn("Fail to close output stream when deleting file: {}", filePath); + } + } + ioExecutor.execute( + () -> { + try { + fs.delete(filePath, false); + LOG.debug("Physical file deleted: {}.", filePath); + } catch (IOException e) { + LOG.warn("Fail to delete file: {}", filePath); + } + }); + } + + // ------------------------------------------------------------------------ + // abstract methods + // ------------------------------------------------------------------------ + + /** + * Get a reused physical file or create one. This will be called in stream creation logic. + * + * <p>Basic logic of file reusing: whenever a physical is needed, this method is called with + * necessary information provided for acquiring a file. The file will not be reused until it is + * written and returned to the reused pool by calling {@link #returnPhysicalFileForNextReuse}. + * + * @param subtaskKey the subtask key for the caller + * @param checkpointId the checkpoint id + * @param scope checkpoint scope + * @return the requested physical file. + * @throws IOException thrown if anything goes wrong with file system. + */ + @Nonnull + protected abstract PhysicalFile getOrCreatePhysicalFileForCheckpoint( + SubtaskKey subtaskKey, long checkpointId, CheckpointedStateScope scope) + throws IOException; + + /** + * Try to return an existing physical file to the manager for next reuse. Delete if needed. + * + * <p>Basic logic of file reusing, see {@link #getOrCreatePhysicalFileForCheckpoint}. + * + * @param subtaskKey the subtask key for the caller + * @param checkpointId in which checkpoint this physical is requested. + * @param physicalFile the returning checkpoint + * @throws IOException thrown if anything goes wrong with file system. + * @see #getOrCreatePhysicalFileForCheckpoint(SubtaskKey, long, CheckpointedStateScope) + */ + protected abstract void returnPhysicalFileForNextReuse( Review Comment: Actually it is used in the tests. It is an essential method working together with `#getOrCreatePhysicalFileForCheckpoint` to implement the file reusing. After FLINK-32073 they will be used in the OutputStream for checkpoint data creation logic. ########## flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/filemerging/FileMergingSnapshotManagerBuilder.java: ########## @@ -0,0 +1,64 @@ +/* + * 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.runtime.checkpoint.filemerging; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.concurrent.Executor; + +/** A builder that builds the {@link FileMergingSnapshotManager}. */ +public class FileMergingSnapshotManagerBuilder { + + private final String id; + + @Nullable private Executor ioExecutor = null; + + /** + * Initialize the builder. + * + * @param id the id of the manager. + */ + public FileMergingSnapshotManagerBuilder(String id) { + this.id = id; + } + + /** + * Set the executor for io operation in manager. If null(default), all io operation will be + * executed synchronously. + */ + public FileMergingSnapshotManagerBuilder setIoExecutor(@Nullable Executor ioExecutor) { + this.ioExecutor = ioExecutor; + return this; + } + + /** + * Create file-merging snapshot manager based on configuration. + * + * <p>TODO (FLINK-32072): Create manager during the initialization of task manager services. + * + * <p>TODO (FLINK-32074): Support another type of FileMergingSnapshotManager that merges files + * across differnet checkpoints. + * + * @return the created manager. + */ + public FileMergingSnapshotManager build() throws IOException { + return new WithinCheckpointFileMergingSnapshotManager( Review Comment: Yes, it is currently a simple builder. But considering we have different types of `FileMergingSnapshotManager` later, this builder will be a unified building entry for different managers. So yes, it have to (better to) be a builder. This PR builds basic framework for the following PRs, so I'd like to put a builder here. -- 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. To unsubscribe, e-mail: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
