jsancio commented on a change in pull request #9512: URL: https://github.com/apache/kafka/pull/9512#discussion_r535474040
########## File path: raft/src/main/java/org/apache/kafka/snapshot/FileRawSnapshotWriter.java ########## @@ -0,0 +1,108 @@ +/* + * 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.snapshot; + +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.channels.FileChannel; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.StandardCopyOption; +import java.nio.file.StandardOpenOption; +import org.apache.kafka.common.utils.Utils; +import org.apache.kafka.raft.OffsetAndEpoch; + +public final class FileRawSnapshotWriter implements RawSnapshotWriter { + private final Path tempSnapshotPath; + private final FileChannel channel; + private final OffsetAndEpoch snapshotId; + private boolean frozen = false; + + private FileRawSnapshotWriter( + Path tempSnapshotPath, + FileChannel channel, + OffsetAndEpoch snapshotId + ) { + this.tempSnapshotPath = tempSnapshotPath; + this.channel = channel; + this.snapshotId = snapshotId; + } + + @Override + public OffsetAndEpoch snapshotId() { + return snapshotId; + } + + @Override + public long sizeInBytes() throws IOException { + return channel.size(); + } + + @Override + public void append(ByteBuffer buffer) throws IOException { + if (frozen) { + throw new IllegalStateException( + String.format("Append not supported. Snapshot is already frozen: id = %s; temp path = %s", snapshotId, tempSnapshotPath) + ); + } + + Utils.writeFully(channel, buffer); + } + + @Override + public boolean isFrozen() { + return frozen; + } + + @Override + public void freeze() throws IOException { + channel.close(); + frozen = true; + + // Set readonly and ignore the result + if (!tempSnapshotPath.toFile().setReadOnly()) { + throw new IOException(String.format("Unable to set file (%s) as read-only", tempSnapshotPath)); + } + + Path destination = Snapshots.moveRename(tempSnapshotPath, snapshotId); + Files.move(tempSnapshotPath, destination, StandardCopyOption.ATOMIC_MOVE); Review comment: I investigated the issue a bit. It look like this utility was introduce to replace these lines in `OffsetCheckpoint.scala`: ```scala // swap new offset checkpoint file with previous one if(!temp.renameTo(file)) { // renameTo() fails on Windows if the destination file exists. file.delete() if(!temp.renameTo(file)) throw new IOException(...) } ``` Looking at the JDK implementation in Windows, `ATOMIC_MOVE` should work in Windows if the target file exists: https://github.com/openjdk/jdk/blob/master/src/java.base/windows/classes/sun/nio/fs/WindowsFileCopy.java#L298-L312 In other words, I think we can keep the code as is in this PR. cc @ijuma ---------------------------------------------------------------- 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
