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HADOOP-11643. Define EC schema API for ErasureCodec. Contributed by Kai Zheng

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drankye 2015-03-05 22:51:52 +08:00 committed by Zhe Zhang
parent 1e1e930407
commit c0945a8971
3 changed files with 261 additions and 0 deletions
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4
hadoop-common-project/hadoop-common/CHANGES-HDFS-EC-7285.txt
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HADOOP-11542. Raw Reed-Solomon coder in pure Java. Contributed by Kai Zheng HADOOP-11542. Raw Reed-Solomon coder in pure Java. Contributed by Kai Zheng
( Kai Zheng ) ( Kai Zheng )
HADOOP-11643. Define EC schema API for ErasureCodec. Contributed by Kai Zheng
( Kai Zheng )

203
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/erasurecode/ECSchema.java Normal file
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/**
* 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.io.erasurecode;
import java.util.Collections;
import java.util.Map;
/**
* Erasure coding schema to housekeeper relevant information.
*/
public class ECSchema {
public static final String NUM_DATA_UNITS_KEY = "k";
public static final String NUM_PARITY_UNITS_KEY = "m";
public static final String CODEC_NAME_KEY = "codec";
public static final String CHUNK_SIZE_KEY = "chunkSize";
public static final int DEFAULT_CHUNK_SIZE = 64 * 1024; // 64K
private String schemaName;
private String codecName;
private Map<String, String> options;
private int numDataUnits;
private int numParityUnits;
private int chunkSize;
/**
* Constructor with schema name and provided options. Note the options may
* contain additional information for the erasure codec to interpret further.
* @param schemaName schema name
* @param options schema options
*/
public ECSchema(String schemaName, Map<String, String> options) {
assert (schemaName != null && ! schemaName.isEmpty());
this.schemaName = schemaName;
if (options == null || options.isEmpty()) {
throw new IllegalArgumentException("No schema options are provided");
}
String codecName = options.get(CODEC_NAME_KEY);
if (codecName == null || codecName.isEmpty()) {
throw new IllegalArgumentException("No codec option is provided");
}
int dataUnits = 0, parityUnits = 0;
try {
if (options.containsKey(NUM_DATA_UNITS_KEY)) {
dataUnits = Integer.parseInt(options.get(NUM_DATA_UNITS_KEY));
}
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Option value " +
options.get(CHUNK_SIZE_KEY) + " for " + CHUNK_SIZE_KEY +
" is found. It should be an integer");
}
try {
if (options.containsKey(NUM_PARITY_UNITS_KEY)) {
parityUnits = Integer.parseInt(options.get(NUM_PARITY_UNITS_KEY));
}
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Option value " +
options.get(CHUNK_SIZE_KEY) + " for " + CHUNK_SIZE_KEY +
" is found. It should be an integer");
}
initWith(codecName, dataUnits, parityUnits, options);
}
/**
* Constructor with key parameters provided. Note the options may contain
* additional information for the erasure codec to interpret further.
* @param schemaName
* @param codecName
* @param numDataUnits
* @param numParityUnits
* @param options
*/
public ECSchema(String schemaName, String codecName,
int numDataUnits, int numParityUnits,
Map<String, String> options) {
assert (schemaName != null && ! schemaName.isEmpty());
assert (codecName != null && ! codecName.isEmpty());
this.schemaName = schemaName;
initWith(codecName, numDataUnits, numParityUnits, options);
}
private void initWith(String codecName, int numDataUnits, int numParityUnits,
Map<String, String> options) {
this.codecName = codecName;
this.numDataUnits = numDataUnits;
this.numParityUnits = numParityUnits;
this.options = options != null ? Collections.unmodifiableMap(options) :
Collections.EMPTY_MAP;
this.chunkSize = DEFAULT_CHUNK_SIZE;
try {
if (options.containsKey(CHUNK_SIZE_KEY)) {
this.chunkSize = Integer.parseInt(options.get(CHUNK_SIZE_KEY));
}
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Option value " +
options.get(CHUNK_SIZE_KEY) + " for " + CHUNK_SIZE_KEY +
" is found. It should be an integer");
}
boolean isFine = numDataUnits > 0 && numParityUnits > 0 && chunkSize > 0;
if (! isFine) {
throw new IllegalArgumentException("Bad codec options are found");
}
}
/**
* Get the schema name
* @return schema name
*/
public String getSchemaName() {
return schemaName;
}
/**
* Get the codec name
* @return codec name
*/
public String getCodecName() {
return codecName;
}
/**
* Get erasure coding options
* @return encoding options
*/
public Map<String, String> getOptions() {
return options;
}
/**
* Get required data units count in a coding group
* @return count of data units
*/
public int getNumDataUnits() {
return numDataUnits;
}
/**
* Get required parity units count in a coding group
* @return count of parity units
*/
public int getNumParityUnits() {
return numParityUnits;
}
/**
* Get chunk buffer size for the erasure encoding/decoding.
* @return chunk buffer size
*/
public int getChunkSize() {
return chunkSize;
}
/**
* Make a meaningful string representation for log output.
* @return string representation
*/
@Override
public String toString() {
StringBuilder sb = new StringBuilder("ECSchema=[");
sb.append("Name=" + schemaName + ",");
sb.append(NUM_DATA_UNITS_KEY + "=" + numDataUnits + ",");
sb.append(NUM_PARITY_UNITS_KEY + "=" + numParityUnits + ",");
sb.append(CHUNK_SIZE_KEY + "=" + chunkSize + ",");
for (String opt : options.keySet()) {
boolean skip = (opt.equals(NUM_DATA_UNITS_KEY) ||
opt.equals(NUM_PARITY_UNITS_KEY) ||
opt.equals(CHUNK_SIZE_KEY));
if (! skip) {
sb.append(opt + "=" + options.get(opt) + ",");
}
}
sb.append("]");
return sb.toString();
}
}

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hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/erasurecode/TestECSchema.java Normal file
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/**
* 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.io.erasurecode;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
import java.util.HashMap;
import java.util.Map;
public class TestECSchema {
@Test
public void testGoodSchema() {
String schemaName = "goodSchema";
int numDataUnits = 6;
int numParityUnits = 3;
int chunkSize = 64 * 1024 * 1024;
String codec = "rs";
String extraOption = "extraOption";
String extraOptionValue = "extraOptionValue";
Map<String, String> options = new HashMap<String, String>();
options.put(ECSchema.NUM_DATA_UNITS_KEY, String.valueOf(numDataUnits));
options.put(ECSchema.NUM_PARITY_UNITS_KEY, String.valueOf(numParityUnits));
options.put(ECSchema.CODEC_NAME_KEY, codec);
options.put(ECSchema.CHUNK_SIZE_KEY, String.valueOf(chunkSize));
options.put(extraOption, extraOptionValue);
ECSchema schema = new ECSchema(schemaName, options);
System.out.println(schema.toString());
assertEquals(schemaName, schema.getSchemaName());
assertEquals(numDataUnits, schema.getNumDataUnits());
assertEquals(numParityUnits, schema.getNumParityUnits());
assertEquals(chunkSize, schema.getChunkSize());
assertEquals(codec, schema.getCodecName());
assertEquals(extraOptionValue, schema.getOptions().get(extraOption));
}
}