/**
* 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.hadoop.raid;
import java.io.IOException;
import java.io.Serializable;
import java.lang.IllegalArgumentException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.ReflectionUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
/**
* A class with the information of a raid codec.
* A raid codec has the information of
* 1. Which ErasureCode used
* 2. Stripe and parity length
* 3. Parity directory location
* 4. Codec priority
*/
public class Codec implements Serializable {
public static final Log LOG = LogFactory.getLog(Codec.class);
public static final String ERASURE_CODE_KEY_PREFIX = "hdfs.raid.erasure.code.";
/**
* Used by ErasureCode.init() to get Code specific extra parameters.
*/
public final String jsonStr;
/**
* id of the codec. Used by policy in raid.xml
*/
public final String id;
/**
* Number of blocks in one stripe
*/
public final int stripeLength;
/**
* Number of parity blocks of the codec for one stripe
*/
public final int parityLength;
/**
* The full class name of the ErasureCode used
*/
public final String erasureCodeClass;
/**
* Human readable description of the codec
*/
public final String description;
/**
* Where to store the parity files
*/
public final String parityDirectory;
public String parityDirectoryPS;
/**
* Where to store the temp parity files
*/
public final String tmpParityDirectory;
public String tmpParityDirectoryPS;
/**
* Where to store the temp har files
*/
public final String tmpHarDirectory;
public String tmpHarDirectoryPS;
/**
* Simulate the block fix or not
*/
public boolean simulateBlockFix;
/**
* Priority of the codec.
*
* Purge parity files:
* When parity files of two Codecs exists, the parity files of the lower
* priority codec will be purged.
*
* Generating parity files:
* When a source files are under two policies, the policy with a higher
* codec priority will be triggered.
*/
public final int priority;
/**
* Is file-level raiding or directory-level raiding
*/
public boolean isDirRaid;
private static List<Codec> codecs;
private static Map<String, Codec> idToCodec;
/**
* Get single instantce of the list of codecs ordered by priority.
*/
public static List<Codec> getCodecs() {
return Codec.codecs;
}
/**
* Get the instance of the codec by id
*/
public static Codec getCodec(String id) {
return idToCodec.get(id);
}
static {
try {
Configuration.addDefaultResource("hdfs-default.xml");
Configuration.addDefaultResource("raid-default.xml");
Configuration.addDefaultResource("hdfs-site.xml");
Configuration.addDefaultResource("raid-site.xml");
initializeCodecs(new Configuration());
} catch (Exception e) {
LOG.fatal("Fail initialize Raid codecs", e);
System.exit(-1);
}
}
public static void initializeCodecs(Configuration conf) throws IOException {
try {
String source = conf.get("raid.codecs.json");
if (source == null) {
codecs = Collections.emptyList();
idToCodec = Collections.emptyMap();
if (LOG.isDebugEnabled()) {
LOG.debug("None Codec is specified");
}
return;
}
JSONArray jsonArray = new JSONArray(source);
List<Codec> localCodecs = new ArrayList<Codec>();
Map<String, Codec> localIdToCodec = new HashMap<String, Codec>();
for (int i = 0; i < jsonArray.length(); ++i) {
Codec codec = new Codec(jsonArray.getJSONObject(i));
localIdToCodec.put(codec.id, codec);
localCodecs.add(codec);
}
Collections.sort(localCodecs, new Comparator<Codec>() {
@Override
public int compare(Codec c1, Codec c2) {
// Higher priority on top
return c2.priority - c1.priority;
}
});
codecs = Collections.unmodifiableList(localCodecs);
idToCodec = Collections.unmodifiableMap(localIdToCodec);
} catch (JSONException e) {
throw new IOException(e);
}
}
private Codec(JSONObject json) throws JSONException {
this.jsonStr = json.toString();
this.id = json.getString("id");
this.parityLength = json.getInt("parity_length");
this.stripeLength = json.getInt("stripe_length");
this.erasureCodeClass = json.getString("erasure_code");
this.parityDirectory = json.getString("parity_dir");
this.priority = json.getInt("priority");
this.description = getJSONString(json, "description", "");
this.isDirRaid = Boolean.parseBoolean(getJSONString(json, "dir_raid", "false"));
this.tmpParityDirectory = getJSONString(
json, "tmp_parity_dir", "/tmp" + this.parityDirectory);
this.tmpHarDirectory = getJSONString(
json, "tmp_har_dir", "/tmp" + this.parityDirectory + "_har");
this.simulateBlockFix = json.getBoolean("simulate_block_fix");
checkDirectory(parityDirectory);
checkDirectory(tmpParityDirectory);
checkDirectory(tmpHarDirectory);
setPathSeparatorDirectories();
}
/**
* Make sure the direcotry string has the format "/a/b/c"
*/
private void checkDirectory(String d) {
if (!d.startsWith(Path.SEPARATOR)) {
throw new IllegalArgumentException("Bad directory:" + d);
}
if (d.endsWith(Path.SEPARATOR)) {
throw new IllegalArgumentException("Bad directory:" + d);
}
}
static private String getJSONString(
JSONObject json, String key, String defaultResult) {
String result = defaultResult;
try {
result = json.getString(key);
} catch (JSONException e) {
}
return result;
}
public ErasureCode createErasureCode(Configuration conf) {
// Create the scheduler
Class<?> erasureCode = null;
try {
erasureCode = conf.getClass(ERASURE_CODE_KEY_PREFIX + this.id,
conf.getClassByName(this.erasureCodeClass));
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
ErasureCode code = (ErasureCode) ReflectionUtils.newInstance(erasureCode,
conf);
code.init(this.stripeLength, this.parityLength);
return code;
}
@Override
public String toString() {
if (jsonStr == null) {
return "Test codec " + id;
} else {
return jsonStr;
}
}
public String getParityPrefix() {
String prefix = this.parityDirectory;
if (!prefix.endsWith(Path.SEPARATOR)) {
prefix += Path.SEPARATOR;
}
return prefix;
}
/**
* Used by unit test only
*/
static void addCodec(Codec codec) {
List<Codec> newCodecs = new ArrayList<Codec>();
newCodecs.addAll(codecs);
newCodecs.add(codec);
codecs = Collections.unmodifiableList(newCodecs);
Map<String, Codec> newIdToCodec = new HashMap<String, Codec>();
newIdToCodec.putAll(idToCodec);
newIdToCodec.put(codec.id, codec);
idToCodec = Collections.unmodifiableMap(newIdToCodec);
}
/**
* Used by unit test only
*/
static void clearCodecs() {
codecs = Collections.emptyList();
idToCodec = Collections.emptyMap();
}
/**
* Used by unit test only
*/
Codec(String id,
int parityLength,
int stripeLength,
String erasureCodeClass,
String parityDirectory,
int priority,
String description,
String tmpParityDirectory,
String tmpHarDirectory,
boolean isDirRaid,
boolean simulateBlockFix) {
this.jsonStr = null;
this.id = id;
this.parityLength = parityLength;
this.stripeLength = stripeLength;
this.erasureCodeClass = erasureCodeClass;
this.parityDirectory = parityDirectory;
this.priority = priority;
this.description = description;
this.tmpParityDirectory = tmpParityDirectory;
this.tmpHarDirectory = tmpHarDirectory;
this.isDirRaid = isDirRaid;
this.simulateBlockFix = simulateBlockFix;
setPathSeparatorDirectories();
}
private void setPathSeparatorDirectories() {
parityDirectoryPS = parityDirectory + Path.SEPARATOR;
tmpParityDirectoryPS = tmpParityDirectory + Path.SEPARATOR;
tmpHarDirectoryPS = tmpHarDirectory + Path.SEPARATOR;
}
}