cmccabe commented on code in PR #12513: URL: https://github.com/apache/kafka/pull/12513#discussion_r949679883
########## metadata/src/main/java/org/apache/kafka/metadata/util/BatchFileReader.java: ########## @@ -0,0 +1,183 @@ +/* + * 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.metadata.util; + +import org.apache.kafka.common.message.LeaderChangeMessage; +import org.apache.kafka.common.message.SnapshotFooterRecord; +import org.apache.kafka.common.message.SnapshotHeaderRecord; +import org.apache.kafka.common.protocol.ByteBufferAccessor; +import org.apache.kafka.common.record.ControlRecordType; +import org.apache.kafka.common.record.FileLogInputStream.FileChannelRecordBatch; +import org.apache.kafka.common.record.FileRecords; +import org.apache.kafka.common.record.Record; +import org.apache.kafka.common.utils.Utils; +import org.apache.kafka.metadata.MetadataRecordSerde; +import org.apache.kafka.raft.Batch; +import org.apache.kafka.server.common.ApiMessageAndVersion; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.File; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Iterator; +import java.util.List; + + +/** + * Reads a log file containing KRaft record batches. + */ +public final class BatchFileReader implements Iterator<BatchFileReader.BatchAndType>, AutoCloseable { + private static final Logger log = LoggerFactory.getLogger(BatchFileReader.class); + + public static class Builder { + private String path = null; + + public Builder setPath(String path) { + this.path = path; + return this; + } + + public BatchFileReader build() throws Exception { + if (path == null) { + throw new RuntimeException("You must specify a path."); + } + FileRecords fileRecords = FileRecords.open(new File(path), false); + try { + return new BatchFileReader(fileRecords); + } catch (Throwable e) { + Utils.closeQuietly(fileRecords, "fileRecords"); + throw e; + } + } + } + + public static class BatchAndType { + private final Batch<ApiMessageAndVersion> batch; + private final boolean isControl; + + public BatchAndType(Batch<ApiMessageAndVersion> batch, boolean isControl) { + this.batch = batch; + this.isControl = isControl; + } + + public Batch<ApiMessageAndVersion> batch() { + return batch; + } + + public boolean isControl() { + return isControl; + } + } + + private final FileRecords fileRecords; + private Iterator<FileChannelRecordBatch> batchIterator; + private final MetadataRecordSerde serde; + + private BatchFileReader(FileRecords fileRecords) { + this.fileRecords = fileRecords; + this.batchIterator = fileRecords.batchIterator(); + this.serde = new MetadataRecordSerde(); + } + + @Override + public boolean hasNext() { + return this.batchIterator.hasNext(); + } + + @Override + public BatchAndType next() { + FileChannelRecordBatch input = batchIterator.next(); + if (input.isControlBatch()) { + return nextControlBatch(input); + } else { + return nextMetadataBatch(input); + } + } + + private BatchAndType nextControlBatch(FileChannelRecordBatch input) { + List<ApiMessageAndVersion> messages = new ArrayList<>(); + for (Iterator<Record> iter = input.iterator(); iter.hasNext(); ) { + Record record = iter.next(); + try { + short typeId = ControlRecordType.parseTypeId(record.key()); + ControlRecordType type = ControlRecordType.fromTypeId(typeId); + switch (type) { + case LEADER_CHANGE: { + LeaderChangeMessage message = new LeaderChangeMessage(); + message.read(new ByteBufferAccessor(record.value()), (short) 0); + messages.add(new ApiMessageAndVersion(message, (short) 0)); + break; + } + case SNAPSHOT_HEADER: { + SnapshotHeaderRecord message = new SnapshotHeaderRecord(); + message.read(new ByteBufferAccessor(record.value()), (short) 0); + messages.add(new ApiMessageAndVersion(message, (short) 0)); + break; + } + case SNAPSHOT_FOOTER: { + SnapshotFooterRecord message = new SnapshotFooterRecord(); + message.read(new ByteBufferAccessor(record.value()), (short) 0); + messages.add(new ApiMessageAndVersion(message, (short) 0)); + break; + } + default: + throw new RuntimeException("Unsupported control record type " + type + " at offset " + + record.offset()); + } + } catch (Throwable e) { + throw new RuntimeException("Unable to read control record at offset " + record.offset(), e); + } + } + return new BatchAndType(Batch.data( + input.baseOffset(), + input.partitionLeaderEpoch(), + input.maxTimestamp(), + input.sizeInBytes(), + messages), true); + } + + private BatchAndType nextMetadataBatch(FileChannelRecordBatch input) { + List<ApiMessageAndVersion> messages = new ArrayList<>(); + for (Record record : input) { + ByteBufferAccessor accessor = new ByteBufferAccessor(record.value()); + try { + ApiMessageAndVersion messageAndVersion = serde.read(accessor, record.valueSize()); + messages.add(messageAndVersion); + } catch (Throwable e) { + log.error("unable to read metadata record at offset {}", record.offset(), e); + } + } + return new BatchAndType(Batch.data( + input.baseOffset(), + input.partitionLeaderEpoch(), + input.maxTimestamp(), + input.sizeInBytes(), + messages), false); + } + + @Override + public void close() { + try { + fileRecords.closeHandlers(); Review Comment: `FileRecords#close` tries to do a flush and trim, which fails because the file descriptor was opened read-only. `FileRecords#close` probably should be fixed to remove the assumption that all files are writable, but I didn't want to expand the scope of this change even more. -- This is an automated message from the Apache Git Service. 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