fredia commented on code in PR #25818: URL: https://github.com/apache/flink/pull/25818#discussion_r1900642660
########## flink-state-backends/flink-statebackend-forst/src/main/java/org/apache/flink/state/forst/fs/filemapping/FileMappingManager.java: ########## @@ -0,0 +1,252 @@ +/* + * 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.forst.fs.filemapping; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.core.fs.FileSystem; +import org.apache.flink.core.fs.Path; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * A manager to manage file mapping of forst file system, including misc file mapping (remote file + * -> local file) and linked mapping (remote file -> remote file). Note, the key/value of mapping + * table must be a file path, directories are maintained by file system itself, directories wouldn't + * be the key/value of mapping table. + */ +public class FileMappingManager { + + private static final Logger LOG = LoggerFactory.getLogger(FileMappingManager.class); + + public static final String SST_SUFFIX = ".sst"; + + private final FileSystem fileSystem; + + private final FileSystem localFileSystem; + + private final HashMap<String, MappingEntry> mappingTable; + + private final String remoteBase; + + private final String localBase; + + public FileMappingManager( + FileSystem fileSystem, + FileSystem localFileSystem, + String remoteBase, + String localBase) { + this.fileSystem = fileSystem; + this.localFileSystem = localFileSystem; + this.mappingTable = new HashMap<>(); + this.remoteBase = remoteBase; + this.localBase = localBase; + } + + /** Create a mapping entry for a file. */ + public RealPath createFile(Path file) { + String fileName = file.toString(); + Preconditions.checkState(!mappingTable.containsKey(fileName)); + if (!fileName.endsWith(SST_SUFFIX) && fileName.startsWith(remoteBase)) { + Path localFile = new Path(localBase, file.getName()); + mappingTable.put( + fileName, new MappingEntry(1, localFileSystem, localFile.toString(), false)); + return new RealPath(localFile, true); + } else { + mappingTable.put(fileName, new MappingEntry(1, fileSystem, fileName, false)); + return new RealPath(file, false); + } + } + + /** Called by link/copy. Directory link is not supported now. */ + public int link(String src, String dst) { + if (src.equals(dst)) { + return -1; + } + // if dst already exist, not allow + if (mappingTable.containsKey(dst)) { + return -1; + } + MappingEntry sourceEntry = mappingTable.get(src); + if (sourceEntry != null) { + sourceEntry.retain(); + mappingTable.putIfAbsent(dst, sourceEntry); + } else { + sourceEntry = new MappingEntry(0, fileSystem, src, false); + sourceEntry.retain(); + mappingTable.put(src, sourceEntry); + sourceEntry.retain(); + mappingTable.put(dst, sourceEntry); + } + LOG.trace("link: {} -> {}", dst, src); + return 0; + } + + /** Get the real path of a file, the real path maybe a local file or a remote file/dir. */ + public RealPath realPath(Path file) { + String fileName = file.toString(); + MappingEntry entry = mappingTable.getOrDefault(fileName, null); + if (!fileName.endsWith(SST_SUFFIX) && fileName.startsWith(remoteBase)) { + if (entry != null) { + return new RealPath(new Path(entry.sourcePath), true); + } + Path localFile = new Path(localBase, file.getName()); + return new RealPath(localFile, true); + } + if (entry != null) { + return new RealPath(new Path(entry.sourcePath), false); + } + return new RealPath(file, false); + } + + public List<String> listByPrefix(String path) { + List<String> linkedPaths = new ArrayList<>(); + for (Map.Entry<String, MappingEntry> entry : mappingTable.entrySet()) { + if (entry.getKey().startsWith(path) && !entry.getValue().isDirectory) { + linkedPaths.add(entry.getKey()); + } + } + return linkedPaths; + } + + /** + * 1. If src can match any key, we only `mark rename`, no physical file would be renamed. 2. If + * src is a directory, all files under src will be renamed, including linked files and local + * files, the directory also would be renamed in file system physically. + * + * @param src the source path + * @param dst the destination path + * @return always return true except for IOException + */ + public boolean renameFile(String src, String dst) throws IOException { + MappingEntry srcEntry = mappingTable.get(src); + if (srcEntry != null) { // rename file + if (mappingTable.containsKey(dst)) { + MappingEntry dstEntry = mappingTable.remove(dst); + dstEntry.release(); + } + mappingTable.remove(src); + mappingTable.put(dst, srcEntry); + } else { // rename directory + // 1. rename file in old directory + List<String> toRename = new ArrayList<>(); + for (String key : mappingTable.keySet()) { + if (isParentDir(key, src) || key.equals(src)) { + toRename.add(key); + } + } + if (!toRename.isEmpty()) { + for (String key : toRename) { + MappingEntry sourceEntry = mappingTable.remove(key); + String renamedDst = key.replace(src, dst); + LOG.trace("rename: {} -> {}", key, renamedDst); + sourceEntry.sourcePath = sourceEntry.sourcePath.replace(src, dst); Review Comment: After discussing offline, we use `link to dst dir + create dst dir + delete src dir` to implement `rename`, the changes of `sourceEntry.sourcePath` have been removed. -- This is an automated message from the Apache Git Service. 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