/**
* 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 com.twitter.distributedlog.metadata;
import com.twitter.distributedlog.DistributedLogConfiguration;
import com.twitter.distributedlog.util.Utils;
import com.twitter.distributedlog.ZooKeeperClient;
import com.twitter.distributedlog.ZooKeeperClientBuilder;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;
import java.net.URI;
import static com.google.common.base.Charsets.UTF_8;
/**
* Metadata of a given DL instance.
*/
public class DLMetadata {
static final Logger LOG = LoggerFactory.getLogger(DLMetadata.class);
static final String LINE_SPLITTER = "\n";
static final String BK_DL_TYPE = "BKDL";
static final int METADATA_FORMAT_VERSION = 1;
// metadata format version
private int metadataFormatVersion = 0;
// underlying dl type
private String dlType;
// underlying dl config
private DLConfig dlConfig;
public DLMetadata(String dlType, DLConfig dlConfig) {
this(dlType, dlConfig, METADATA_FORMAT_VERSION);
}
DLMetadata(String dlType, DLConfig dlConfig, int metadataFormatVersion) {
this.dlType = dlType;
this.dlConfig = dlConfig;
this.metadataFormatVersion = metadataFormatVersion;
}
/**
* @return DL type
*/
public String getDLType() {
return dlType;
}
/**
* @return DL Config
*/
public DLConfig getDLConfig() {
return dlConfig;
}
/**
* Serialize the DL metadata into bytes array.
*
* @return bytes of DL metadata.
*/
public byte[] serialize() {
StringBuilder sb = new StringBuilder();
sb.append(metadataFormatVersion).append(LINE_SPLITTER);
sb.append(dlType).append(LINE_SPLITTER);
sb.append(dlConfig.serialize());
LOG.debug("Serialized dl metadata {}.", sb);
return sb.toString().getBytes(UTF_8);
}
@Override
public int hashCode() {
return dlType.hashCode() * 13 + dlConfig.hashCode();
}
@Override
public String toString() {
return new String(serialize(), UTF_8);
}
public void update(URI uri) throws IOException {
DistributedLogConfiguration conf = new DistributedLogConfiguration();
ZooKeeperClient zkc = ZooKeeperClientBuilder.newBuilder()
.sessionTimeoutMs(conf.getZKSessionTimeoutMilliseconds())
.retryThreadCount(conf.getZKClientNumberRetryThreads())
.requestRateLimit(conf.getZKRequestRateLimit())
.zkAclId(conf.getZkAclId())
.uri(uri)
.build();
byte[] data = serialize();
try {
zkc.get().setData(uri.getPath(), data, -1);
} catch (KeeperException e) {
throw new IOException("Fail to update dl metadata " + new String(data, UTF_8)
+ " to uri " + uri, e);
} catch (InterruptedException e) {
throw new IOException("Interrupted when updating dl metadata "
+ new String(data, UTF_8) + " to uri " + uri, e);
} finally {
zkc.close();
}
}
@Override
public boolean equals(Object o) {
if (!(o instanceof DLMetadata)) {
return false;
}
DLMetadata other = (DLMetadata) o;
return dlType.equals(other.dlType) && dlConfig.equals(other.dlConfig);
}
public void create(URI uri) throws IOException {
DistributedLogConfiguration conf = new DistributedLogConfiguration();
ZooKeeperClient zkc = ZooKeeperClientBuilder.newBuilder()
.sessionTimeoutMs(conf.getZKSessionTimeoutMilliseconds())
.retryThreadCount(conf.getZKClientNumberRetryThreads())
.requestRateLimit(conf.getZKRequestRateLimit())
.zkAclId(conf.getZkAclId())
.uri(uri)
.build();
byte[] data = serialize();
try {
Utils.zkCreateFullPathOptimistic(zkc, uri.getPath(), data,
zkc.getDefaultACL(), CreateMode.PERSISTENT);
} catch (KeeperException e) {
throw new IOException("Fail to write dl metadata " + new String(data, UTF_8)
+ " to uri " + uri, e);
} catch (InterruptedException e) {
throw new IOException("Interrupted when writing dl metadata " + new String(data, UTF_8)
+ " to uri " + uri, e);
} finally {
zkc.close();
}
}
public static void unbind(URI uri) throws IOException {
DistributedLogConfiguration conf = new DistributedLogConfiguration();
ZooKeeperClient zkc = ZooKeeperClientBuilder.newBuilder()
.sessionTimeoutMs(conf.getZKSessionTimeoutMilliseconds())
.retryThreadCount(conf.getZKClientNumberRetryThreads())
.requestRateLimit(conf.getZKRequestRateLimit())
.zkAclId(conf.getZkAclId())
.uri(uri)
.build();
byte[] data = new byte[0];
try {
zkc.get().setData(uri.getPath(), data, -1);
} catch (KeeperException ke) {
throw new IOException("Fail to unbound dl metadata on uri " + uri, ke);
} catch (InterruptedException ie) {
throw new IOException("Interrupted when unbinding dl metadata on uri " + uri, ie);
} finally {
zkc.close();
}
}
/**
* Deserialize dl metadata of given <i>uri</i> from a given bytes array.
*
* @param uri
* uri that stored dl metadata bindings
* @param data
* bytes of dl metadata
* @return dl metadata
* @throws IOException if failed to parse the bytes array
*/
public static DLMetadata deserialize(URI uri, byte[] data) throws IOException {
String metadata = new String(data, UTF_8);
LOG.debug("Parsing dl metadata {}.", metadata);
BufferedReader br = new BufferedReader(new StringReader(metadata));
String versionLine = br.readLine();
if (null == versionLine) {
throw new IOException("Empty DL Metadata.");
}
int version;
try {
version = Integer.parseInt(versionLine);
} catch (NumberFormatException nfe) {
version = -1;
}
if (METADATA_FORMAT_VERSION != version) {
throw new IOException("Metadata version not compatible. Expected "
+ METADATA_FORMAT_VERSION + " but got " + version);
}
String type = br.readLine();
if (!BK_DL_TYPE.equals(type)) {
throw new IOException("Invalid DL type : " + type);
}
DLConfig dlConfig = new BKDLConfig(uri);
StringBuilder sb = new StringBuilder();
String line;
while (null != (line = br.readLine())) {
sb.append(line);
}
dlConfig.deserialize(sb.toString().getBytes(UTF_8));
return new DLMetadata(type, dlConfig, version);
}
public static DLMetadata create(BKDLConfig bkdlConfig) {
return new DLMetadata(BK_DL_TYPE, bkdlConfig);
}
}