/**
* 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.zookeeper.server.persistence;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.zip.Adler32;
import java.util.zip.Checksum;
import org.apache.jute.BinaryInputArchive;
import org.apache.jute.BinaryOutputArchive;
import org.apache.jute.InputArchive;
import org.apache.jute.OutputArchive;
import org.apache.jute.Record;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.zookeeper.server.util.SerializeUtils;
import org.apache.zookeeper.txn.TxnHeader;
/**
* This class implements the TxnLog interface. It provides api's
* to access the txnlogs and add entries to it.
* <p>
* The format of a Transactional log is as follows:
* <blockquote><pre>
* LogFile:
* FileHeader TxnList ZeroPad
*
* FileHeader: {
* magic 4bytes (ZKLG)
* version 4bytes
* dbid 8bytes
* }
*
* TxnList:
* Txn || Txn TxnList
*
* Txn:
* checksum Txnlen TxnHeader Record 0x42
*
* checksum: 8bytes Adler32 is currently used
* calculated across payload -- Txnlen, TxnHeader, Record and 0x42
*
* Txnlen:
* len 4bytes
*
* TxnHeader: {
* sessionid 8bytes
* cxid 4bytes
* zxid 8bytes
* time 8bytes
* type 4bytes
* }
*
* Record:
* See Jute definition file for details on the various record types
*
* ZeroPad:
* 0 padded to EOF (filled during preallocation stage)
* </pre></blockquote>
*/
public class FileTxnLog implements TxnLog {
private static final Logger LOG;
static long preAllocSize = 65536 * 1024;
public final static int TXNLOG_MAGIC =
ByteBuffer.wrap("ZKLG".getBytes()).getInt();
public final static int VERSION = 2;
static {
LOG = LoggerFactory.getLogger(FileTxnLog.class);
String size = System.getProperty("zookeeper.preAllocSize");
if (size != null) {
try {
preAllocSize = Long.parseLong(size) * 1024;
} catch (NumberFormatException e) {
LOG.warn(size + " is not a valid value for preAllocSize");
}
}
}
long lastZxidSeen;
volatile BufferedOutputStream logStream = null;
volatile OutputArchive oa;
volatile FileOutputStream fos = null;
File logDir;
private final boolean forceSync = !System.getProperty("zookeeper.forceSync", "yes").equals("no");;
long dbId;
private LinkedList<FileOutputStream> streamsToFlush =
new LinkedList<FileOutputStream>();
long currentSize;
File logFileWrite = null;
/**
* constructor for FileTxnLog. Take the directory
* where the txnlogs are stored
* @param logDir the directory where the txnlogs are stored
*/
public FileTxnLog(File logDir) {
this.logDir = logDir;
}
/**
* method to allow setting preallocate size
* of log file to pad the file.
* @param size the size to set to in bytes
*/
public static void setPreallocSize(long size) {
preAllocSize = size;
}
/**
* creates a checksum alogrithm to be used
* @return the checksum used for this txnlog
*/
protected Checksum makeChecksumAlgorithm(){
return new Adler32();
}
/**
* rollover the current log file to a new one.
* @throws IOException
*/
public synchronized void rollLog() throws IOException {
if (logStream != null) {
this.logStream.flush();
this.logStream = null;
oa = null;
}
}
/**
* close all the open file handles
* @throws IOException
*/
public synchronized void close() throws IOException {
if (logStream != null) {
logStream.close();
}
for (FileOutputStream log : streamsToFlush) {
log.close();
}
}
/**
* append an entry to the transaction log
* @param hdr the header of the transaction
* @param txn the transaction part of the entry
* returns true iff something appended, otw false
*/
public synchronized boolean append(TxnHeader hdr, Record txn)
throws IOException
{
if (hdr != null) {
if (hdr.getZxid() <= lastZxidSeen) {
LOG.warn("Current zxid " + hdr.getZxid()
+ " is <= " + lastZxidSeen + " for "
+ hdr.getType());
}
if (logStream==null) {
if(LOG.isInfoEnabled()){
LOG.info("Creating new log file: log." +
Long.toHexString(hdr.getZxid()));
}
logFileWrite = new File(logDir, ("log." +
Long.toHexString(hdr.getZxid())));
fos = new FileOutputStream(logFileWrite);
logStream=new BufferedOutputStream(fos);
oa = BinaryOutputArchive.getArchive(logStream);
FileHeader fhdr = new FileHeader(TXNLOG_MAGIC,VERSION, dbId);
fhdr.serialize(oa, "fileheader");
// Make sure that the magic number is written before padding.
logStream.flush();
currentSize = fos.getChannel().position();
streamsToFlush.add(fos);
}
padFile(fos);
byte[] buf = Util.marshallTxnEntry(hdr, txn);
if (buf == null || buf.length == 0) {
throw new IOException("Faulty serialization for header " +
"and txn");
}
Checksum crc = makeChecksumAlgorithm();
crc.update(buf, 0, buf.length);
oa.writeLong(crc.getValue(), "txnEntryCRC");
Util.writeTxnBytes(oa, buf);
return true;
}
return false;
}
/**
* pad the current file to increase its size
* @param out the outputstream to be padded
* @throws IOException
*/
private void padFile(FileOutputStream out) throws IOException {
currentSize = Util.padLogFile(out, currentSize, preAllocSize);
}
/**
* Find the log file that starts at, or just before, the snapshot. Return
* this and all subsequent logs. Results are ordered by zxid of file,
* ascending order.
* @param logDirList array of files
* @param snapshotZxid return files at, or before this zxid
* @return
*/
public static File[] getLogFiles(File[] logDirList,long snapshotZxid) {
List<File> files = Util.sortDataDir(logDirList, "log", true);
long logZxid = 0;
// Find the log file that starts before or at the same time as the
// zxid of the snapshot
for (File f : files) {
long fzxid = Util.getZxidFromName(f.getName(), "log");
if (fzxid > snapshotZxid) {
continue;
}
// the files
// are sorted with zxid's
if (fzxid > logZxid) {
logZxid = fzxid;
}
}
List<File> v=new ArrayList<File>(5);
for (File f : files) {
long fzxid = Util.getZxidFromName(f.getName(), "log");
if (fzxid < logZxid) {
continue;
}
v.add(f);
}
return v.toArray(new File[0]);
}
/**
* get the last zxid that was logged in the transaction logs
* @return the last zxid logged in the transaction logs
*/
public long getLastLoggedZxid() {
File[] files = getLogFiles(logDir.listFiles(), 0);
long maxLog=files.length>0?
Util.getZxidFromName(files[files.length-1].getName(),"log"):-1;
// if a log file is more recent we must scan it to find
// the highest zxid
long zxid = maxLog;
try {
FileTxnLog txn = new FileTxnLog(logDir);
TxnIterator itr = txn.read(maxLog);
while (true) {
if(!itr.next())
break;
TxnHeader hdr = itr.getHeader();
zxid = hdr.getZxid();
}
} catch (IOException e) {
LOG.warn("Unexpected exception", e);
}
return zxid;
}
/**
* commit the logs. make sure that evertyhing hits the
* disk
*/
public synchronized void commit() throws IOException {
if (logStream != null) {
logStream.flush();
}
for (FileOutputStream log : streamsToFlush) {
log.flush();
if (forceSync) {
log.getChannel().force(false);
}
}
while (streamsToFlush.size() > 1) {
streamsToFlush.removeFirst().close();
}
}
/**
* start reading all the transactions from the given zxid
* @param zxid the zxid to start reading transactions from
* @return returns an iterator to iterate through the transaction
* logs
*/
public TxnIterator read(long zxid) throws IOException {
return new FileTxnIterator(logDir, zxid);
}
/**
* truncate the current transaction logs
* @param zxid the zxid to truncate the logs to
* @return true if successful false if not
*/
public boolean truncate(long zxid) throws IOException {
FileTxnIterator itr = new FileTxnIterator(this.logDir, zxid);
PositionInputStream input = itr.inputStream;
long pos = input.getPosition();
// now, truncate at the current position
RandomAccessFile raf=new RandomAccessFile(itr.logFile,"rw");
raf.setLength(pos);
raf.close();
while(itr.goToNextLog()) {
if (!itr.logFile.delete()) {
LOG.warn("Unable to truncate " + itr.logFile);
}
}
return true;
}
/**
* read the header of the transaction file
* @param file the transaction file to read
* @return header that was read fomr the file
* @throws IOException
*/
private static FileHeader readHeader(File file) throws IOException {
InputStream is =null;
try {
is = new BufferedInputStream(new FileInputStream(file));
InputArchive ia=BinaryInputArchive.getArchive(is);
FileHeader hdr = new FileHeader();
hdr.deserialize(ia, "fileheader");
return hdr;
} finally {
try {
if (is != null) is.close();
} catch (IOException e) {
LOG.warn("Ignoring exception during close", e);
}
}
}
/**
* the dbid of this transaction database
* @return the dbid of this database
*/
public long getDbId() throws IOException {
FileTxnIterator itr = new FileTxnIterator(logDir, 0);
FileHeader fh=readHeader(itr.logFile);
itr.close();
if(fh==null)
throw new IOException("Unsupported Format.");
return fh.getDbid();
}
/**
* the forceSync value. true if forceSync is enabled, false otherwise.
* @return the forceSync value
*/
public boolean isForceSync() {
return forceSync;
}
/**
* a class that keeps track of the position
* in the input stream. The position points to offset
* that has been consumed by the applications. It can
* wrap buffered input streams to provide the right offset
* for the application.
*/
static class PositionInputStream extends FilterInputStream {
long position;
protected PositionInputStream(InputStream in) {
super(in);
position = 0;
}
@Override
public int read() throws IOException {
int rc = super.read();
if (rc > -1) {
position++;
}
return rc;
}
public int read(byte[] b) throws IOException {
int rc = super.read(b);
if (rc > 0) {
position += rc;
}
return rc;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
int rc = super.read(b, off, len);
if (rc > 0) {
position += rc;
}
return rc;
}
@Override
public long skip(long n) throws IOException {
long rc = super.skip(n);
if (rc > 0) {
position += rc;
}
return rc;
}
public long getPosition() {
return position;
}
@Override
public boolean markSupported() {
return false;
}
@Override
public void mark(int readLimit) {
throw new UnsupportedOperationException("mark");
}
@Override
public void reset() {
throw new UnsupportedOperationException("reset");
}
}
/**
* this class implements the txnlog iterator interface
* which is used for reading the transaction logs
*/
public static class FileTxnIterator implements TxnLog.TxnIterator {
File logDir;
long zxid;
TxnHeader hdr;
Record record;
File logFile;
InputArchive ia;
static final String CRC_ERROR="CRC check failed";
PositionInputStream inputStream=null;
//stored files is the list of files greater than
//the zxid we are looking for.
private ArrayList<File> storedFiles;
/**
* create an iterator over a transaction database directory
* @param logDir the transaction database directory
* @param zxid the zxid to start reading from
* @throws IOException
*/
public FileTxnIterator(File logDir, long zxid) throws IOException {
this.logDir = logDir;
this.zxid = zxid;
init();
}
/**
* initialize to the zxid specified
* this is inclusive of the zxid
* @throws IOException
*/
void init() throws IOException {
storedFiles = new ArrayList<File>();
List<File> files = Util.sortDataDir(FileTxnLog.getLogFiles(logDir.listFiles(), 0), "log", false);
for (File f: files) {
if (Util.getZxidFromName(f.getName(), "log") >= zxid) {
storedFiles.add(f);
}
// add the last logfile that is less than the zxid
else if (Util.getZxidFromName(f.getName(), "log") < zxid) {
storedFiles.add(f);
break;
}
}
goToNextLog();
if (!next())
return;
while (hdr.getZxid() < zxid) {
if (!next())
return;
}
}
/**
* go to the next logfile
* @return true if there is one and false if there is no
* new file to be read
* @throws IOException
*/
private boolean goToNextLog() throws IOException {
if (storedFiles.size() > 0) {
this.logFile = storedFiles.remove(storedFiles.size()-1);
ia = createInputArchive(this.logFile);
return true;
}
return false;
}
/**
* read the header from the inputarchive
* @param ia the inputarchive to be read from
* @param is the inputstream
* @throws IOException
*/
protected void inStreamCreated(InputArchive ia, InputStream is)
throws IOException{
FileHeader header= new FileHeader();
header.deserialize(ia, "fileheader");
if (header.getMagic() != FileTxnLog.TXNLOG_MAGIC) {
throw new IOException("Transaction log: " + this.logFile + " has invalid magic number "
+ header.getMagic()
+ " != " + FileTxnLog.TXNLOG_MAGIC);
}
}
/**
* Invoked to indicate that the input stream has been created.
* @param ia input archive
* @param is file input stream associated with the input archive.
* @throws IOException
**/
protected InputArchive createInputArchive(File logFile) throws IOException {
if(inputStream==null){
inputStream= new PositionInputStream(new BufferedInputStream(new FileInputStream(logFile)));
LOG.debug("Created new input stream " + logFile);
ia = BinaryInputArchive.getArchive(inputStream);
inStreamCreated(ia,inputStream);
LOG.debug("Created new input archive " + logFile);
}
return ia;
}
/**
* create a checksum algorithm
* @return the checksum algorithm
*/
protected Checksum makeChecksumAlgorithm(){
return new Adler32();
}
/**
* the iterator that moves to the next transaction
* @return true if there is more transactions to be read
* false if not.
*/
public boolean next() throws IOException {
if (ia == null) {
return false;
}
try {
long crcValue = ia.readLong("crcvalue");
byte[] bytes = Util.readTxnBytes(ia);
// Since we preallocate, we define EOF to be an
if (bytes == null || bytes.length==0)
throw new EOFException("Failed to read");
// EOF or corrupted record
// validate CRC
Checksum crc = makeChecksumAlgorithm();
crc.update(bytes, 0, bytes.length);
if (crcValue != crc.getValue())
throw new IOException(CRC_ERROR);
if (bytes == null || bytes.length == 0)
return false;
hdr = new TxnHeader();
record = SerializeUtils.deserializeTxn(bytes, hdr);
} catch (EOFException e) {
LOG.debug("EOF excepton " + e);
inputStream.close();
inputStream = null;
ia = null;
hdr = null;
// this means that the file has ended
// we shoud go to the next file
if (!goToNextLog()) {
return false;
}
// if we went to the next log file, we should call next() again
return next();
}
return true;
}
/**
* reutrn the current header
* @return the current header that
* is read
*/
public TxnHeader getHeader() {
return hdr;
}
/**
* return the current transaction
* @return the current transaction
* that is read
*/
public Record getTxn() {
return record;
}
/**
* close the iterator
* and release the resources.
*/
public void close() throws IOException {
inputStream.close();
}
}
}