/*
* 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.flume.channel.file;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.common.io.Files;
class EventQueueBackingStoreFactory {
private static final Logger LOG = LoggerFactory
.getLogger(EventQueueBackingStoreFactory.class);
private EventQueueBackingStoreFactory() {}
static EventQueueBackingStore get(File checkpointFile, int capacity,
String name) throws Exception {
return get(checkpointFile, capacity, name, true);
}
static EventQueueBackingStore get(File checkpointFile, int capacity,
String name, boolean upgrade) throws Exception {
return get(checkpointFile, null, capacity, name, upgrade, false);
}
static EventQueueBackingStore get(File checkpointFile,
File backupCheckpointDir, int capacity,String name,
boolean upgrade, boolean shouldBackup) throws Exception {
File metaDataFile = Serialization.getMetaDataFile(checkpointFile);
RandomAccessFile checkpointFileHandle = null;
try {
boolean checkpointExists = checkpointFile.exists();
boolean metaDataExists = metaDataFile.exists();
if(metaDataExists) {
// if we have a metadata file but no checkpoint file, we have a problem
// delete everything in the checkpoint directory and force
// a full replay.
if(!checkpointExists || checkpointFile.length() == 0) {
LOG.warn("MetaData file for checkpoint "
+ " exists but checkpoint does not. Checkpoint = " + checkpointFile
+ ", metaDataFile = " + metaDataFile);
throw new BadCheckpointException(
"The last checkpoint was not completed correctly, " +
"since Checkpoint file does not exist while metadata " +
"file does.");
}
}
// brand new, use v3
if(!checkpointExists) {
if(!checkpointFile.createNewFile()) {
throw new IOException("Cannot create " + checkpointFile);
}
return new EventQueueBackingStoreFileV3(checkpointFile,
capacity, name, backupCheckpointDir, shouldBackup);
}
// v3 due to meta file, version will be checked by backing store
if(metaDataExists) {
return new EventQueueBackingStoreFileV3(checkpointFile, capacity,
name, backupCheckpointDir, shouldBackup);
}
checkpointFileHandle = new RandomAccessFile(checkpointFile, "r");
int version = (int)checkpointFileHandle.readLong();
if(Serialization.VERSION_2 == version) {
if(upgrade) {
return upgrade(checkpointFile, capacity, name, backupCheckpointDir,
shouldBackup);
}
return new EventQueueBackingStoreFileV2(checkpointFile, capacity, name);
}
LOG.error("Found version " + Integer.toHexString(version) + " in " +
checkpointFile);
throw new BadCheckpointException("Checkpoint file exists with " +
Serialization.VERSION_3 + " but no metadata file found.");
} finally {
if(checkpointFileHandle != null) {
try {
checkpointFileHandle.close();
} catch(IOException e) {
LOG.warn("Unable to close " + checkpointFile, e);
}
}
}
}
private static EventQueueBackingStore upgrade(File checkpointFile,
int capacity, String name, File backupCheckpointDir,
boolean shouldBackup)
throws Exception {
LOG.info("Attempting upgrade of " + checkpointFile + " for " + name);
EventQueueBackingStoreFileV2 backingStoreV2 =
new EventQueueBackingStoreFileV2(checkpointFile, capacity, name);
String backupName = checkpointFile.getName() + "-backup-"
+ System.currentTimeMillis();
Files.copy(checkpointFile,
new File(checkpointFile.getParentFile(), backupName));
File metaDataFile = Serialization.getMetaDataFile(checkpointFile);
EventQueueBackingStoreFileV3.upgrade(backingStoreV2, checkpointFile,
metaDataFile);
return new EventQueueBackingStoreFileV3(checkpointFile, capacity, name,
backupCheckpointDir, shouldBackup);
}
}