/**
* Copyright 2013 Boundary, Inc.
*
* Licensed 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 com.boundary.zoocreeper;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
import com.google.common.base.Preconditions;
import com.google.common.io.Closeables;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Stat;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.CmdLineParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Collections;
import java.util.List;
import java.util.zip.GZIPOutputStream;
/**
* Backup command.
*/
public class Backup {
private static final Logger LOGGER = LoggerFactory.getLogger(Backup.class);
private static final JsonFactory JSON_FACTORY = new JsonFactory();
public static final String FIELD_AVERSION = "aversion";
public static final String FIELD_CTIME = "ctime";
public static final String FIELD_CVERSION = "cversion";
public static final String FIELD_CZXID = "czxid";
public static final String FIELD_EPHEMERAL_OWNER = "ephemeralOwner";
public static final String FIELD_MTIME = "mtime";
public static final String FIELD_MZXID = "mzxid";
public static final String FIELD_PZXID = "pzxid";
public static final String FIELD_VERSION = "version";
public static final String FIELD_DATA = "data";
public static final String FIELD_ACLS = "acls";
public static final String FIELD_ACL_ID = "id";
public static final String FIELD_ACL_SCHEME = "scheme";
public static final String FIELD_ACL_PERMS = "perms";
private final BackupOptions options;
public Backup(BackupOptions options) {
this.options = Preconditions.checkNotNull(options);
}
public void backup(OutputStream os) throws InterruptedException, IOException, KeeperException {
JsonGenerator jgen = null;
ZooKeeper zk = null;
try {
zk = options.createZooKeeper(LOGGER);
jgen = JSON_FACTORY.createGenerator(os);
if (options.prettyPrint) {
jgen.setPrettyPrinter(new DefaultPrettyPrinter());
}
jgen.writeStartObject();
if (zk.exists(options.rootPath, false) == null) {
LOGGER.warn("Root path not found: {}", options.rootPath);
} else {
doBackup(zk, jgen, options.rootPath);
}
jgen.writeEndObject();
} finally {
if (jgen != null) {
jgen.close();
}
if (zk != null) {
zk.close();
}
}
}
private static String createFullPath(String path, String childPath) {
final String fullChildPath;
if (path.endsWith("/")) {
fullChildPath = path + childPath;
} else {
fullChildPath = path + '/' + childPath;
}
return fullChildPath;
}
private static <T> List<T> nullToEmpty(List<T> original) {
return (original != null) ? original : Collections.<T> emptyList();
}
private void doBackup(ZooKeeper zk, JsonGenerator jgen, String path)
throws KeeperException, InterruptedException, IOException {
try {
final Stat stat = new Stat();
List<ACL> acls = nullToEmpty(zk.getACL(path, stat));
if (stat.getEphemeralOwner() != 0 && !options.backupEphemeral) {
LOGGER.debug("Skipping ephemeral node: {}", path);
return;
}
final Stat dataStat = new Stat();
byte[] data = zk.getData(path, false, dataStat);
for (int i = 0; stat.compareTo(dataStat) != 0 && i < options.numRetries; i++) {
LOGGER.warn("Retrying getACL / getData to read consistent state");
acls = zk.getACL(path, stat);
data = zk.getData(path, false, dataStat);
}
if (stat.compareTo(dataStat) != 0) {
throw new IllegalStateException("Unable to read consistent data for znode: " + path);
}
LOGGER.debug("Backing up node: {}", path);
dumpNode(jgen, path, stat, acls, data);
final List<String> childPaths = nullToEmpty(zk.getChildren(path, false, null));
Collections.sort(childPaths);
for (String childPath : childPaths) {
final String fullChildPath = createFullPath(path, childPath);
if (!this.options.isPathExcluded(LOGGER, fullChildPath)) {
if (this.options.isPathIncluded(LOGGER, fullChildPath)) {
doBackup(zk, jgen, fullChildPath);
}
}
}
} catch (NoNodeException e) {
LOGGER.warn("Node disappeared during backup: {}", path);
}
}
private void dumpNode(JsonGenerator jgen, String path, Stat stat, List<ACL> acls, byte[] data) throws IOException {
jgen.writeObjectFieldStart(path);
// The number of changes to the ACL of this znode.
jgen.writeNumberField(FIELD_AVERSION, stat.getAversion());
// The time in milliseconds from epoch when this znode was created.
jgen.writeNumberField(FIELD_CTIME, stat.getCtime());
// The number of changes to the children of this znode.
jgen.writeNumberField(FIELD_CVERSION, stat.getCversion());
// The zxid of the change that caused this znode to be created.
jgen.writeNumberField(FIELD_CZXID, stat.getCzxid());
// The length of the data field of this znode.
// jgen.writeNumberField("dataLength", stat.getDataLength());
// The session id of the owner of this znode if the znode is an ephemeral node. If it is not an ephemeral node,
// it will be zero.
jgen.writeNumberField(FIELD_EPHEMERAL_OWNER, stat.getEphemeralOwner());
// The time in milliseconds from epoch when this znode was last modified.
jgen.writeNumberField(FIELD_MTIME, stat.getMtime());
// The zxid of the change that last modified this znode.
jgen.writeNumberField(FIELD_MZXID, stat.getMzxid());
// The number of children of this znode.
jgen.writeNumberField("numChildren", stat.getNumChildren());
// last modified children?
jgen.writeNumberField(FIELD_PZXID, stat.getPzxid());
// The number of changes to the data of this znode.
jgen.writeNumberField(FIELD_VERSION, stat.getVersion());
if (data != null) {
jgen.writeBinaryField(FIELD_DATA, data);
} else {
jgen.writeNullField(FIELD_DATA);
}
jgen.writeArrayFieldStart(FIELD_ACLS);
for (ACL acl : acls) {
jgen.writeStartObject();
jgen.writeStringField(FIELD_ACL_ID, acl.getId().getId());
jgen.writeStringField(FIELD_ACL_SCHEME, acl.getId().getScheme());
jgen.writeNumberField(FIELD_ACL_PERMS, acl.getPerms());
jgen.writeEndObject();
}
jgen.writeEndArray();
jgen.writeEndObject();
}
private static void usage(CmdLineParser parser, int exitCode) {
System.err.println(Backup.class.getName() + " [options...] arguments...");
parser.printUsage(System.err);
System.exit(exitCode);
}
public static void main(String[] args) throws IOException, InterruptedException, KeeperException {
BackupOptions options = new BackupOptions();
CmdLineParser parser = new CmdLineParser(options);
try {
parser.parseArgument(args);
if (options.help) {
usage(parser, 0);
}
} catch (CmdLineException e) {
if (!options.help) {
System.err.println(e.getLocalizedMessage());
}
usage(parser, options.help ? 0 : 1);
}
if (options.verbose) {
LoggingUtils.enableDebugLogging(Backup.class.getPackage().getName());
}
Backup backup = new Backup(options);
OutputStream os;
if ("-".equals(options.outputFile)) {
os = System.out;
} else {
os = new BufferedOutputStream(new FileOutputStream(options.outputFile));
}
try {
if (options.compress) {
os = new GZIPOutputStream(os);
}
backup.backup(os);
} finally {
os.flush();
Closeables.close(os, true);
}
}
}
