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Add CompressibleBytesOutputStream for compression (#24927)
This is a follow-up to #23941. Currently there are a number of complexities related to compression. The raw DeflaterOutputStream must be closed prior to sending bytes to ensure that EOS bytes are written. But the underlying ReleasableBytesStreamOutput cannot be closed until the bytes are sent to ensure that the bytes are not reused. Right now we have three different stream references hanging around in TCPTransport to handle this complexity. This commit introduces CompressibleBytesOutputStream to be one stream implemenation that will behave properly with or without compression enabled.
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core/src/main/java/org/elasticsearch/transport/CompressibleBytesOutputStream.java
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/* | ||
* Licensed to Elasticsearch under one or more contributor | ||
* license agreements. See the NOTICE file distributed with | ||
* this work for additional information regarding copyright | ||
* ownership. Elasticsearch 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. | ||
*/ | ||
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package org.elasticsearch.transport; | ||
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import org.apache.lucene.util.IOUtils; | ||
import org.elasticsearch.common.bytes.BytesReference; | ||
import org.elasticsearch.common.compress.CompressorFactory; | ||
import org.elasticsearch.common.io.Streams; | ||
import org.elasticsearch.common.io.stream.BytesStream; | ||
import org.elasticsearch.common.io.stream.StreamOutput; | ||
import org.elasticsearch.common.lease.Releasable; | ||
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import java.io.IOException; | ||
import java.util.zip.DeflaterOutputStream; | ||
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/** | ||
* This class exists to provide a stream with optional compression. This is useful as using compression | ||
* requires that the underlying {@link DeflaterOutputStream} be closed to write EOS bytes. However, the | ||
* {@link BytesStream} should not be closed yet, as we have not used the bytes. This class handles these | ||
* intricacies. | ||
* | ||
* {@link CompressibleBytesOutputStream#materializeBytes()} should be called when all the bytes have been | ||
* written to this stream. If compression is enabled, the proper EOS bytes will be written at that point. | ||
* The underlying {@link BytesReference} will be returned. | ||
* | ||
* {@link CompressibleBytesOutputStream#close()} should be called when the bytes are no longer needed and | ||
* can be safely released. | ||
*/ | ||
final class CompressibleBytesOutputStream extends StreamOutput implements Releasable { | ||
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private final StreamOutput stream; | ||
private final BytesStream bytesStreamOutput; | ||
private final boolean shouldCompress; | ||
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CompressibleBytesOutputStream(BytesStream bytesStreamOutput, boolean shouldCompress) throws IOException { | ||
this.bytesStreamOutput = bytesStreamOutput; | ||
this.shouldCompress = shouldCompress; | ||
if (shouldCompress) { | ||
this.stream = CompressorFactory.COMPRESSOR.streamOutput(Streams.flushOnCloseStream(bytesStreamOutput)); | ||
} else { | ||
this.stream = bytesStreamOutput; | ||
} | ||
} | ||
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/** | ||
* This method ensures that compression is complete and returns the underlying bytes. | ||
* | ||
* @return bytes underlying the stream | ||
* @throws IOException if an exception occurs when writing or flushing | ||
*/ | ||
BytesReference materializeBytes() throws IOException { | ||
// If we are using compression the stream needs to be closed to ensure that EOS marker bytes are written. | ||
// The actual ReleasableBytesStreamOutput will not be closed yet as it is wrapped in flushOnCloseStream when | ||
// passed to the deflater stream. | ||
if (shouldCompress) { | ||
stream.close(); | ||
} | ||
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return bytesStreamOutput.bytes(); | ||
} | ||
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@Override | ||
public void writeByte(byte b) throws IOException { | ||
stream.write(b); | ||
} | ||
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@Override | ||
public void writeBytes(byte[] b, int offset, int length) throws IOException { | ||
stream.writeBytes(b, offset, length); | ||
} | ||
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@Override | ||
public void flush() throws IOException { | ||
stream.flush(); | ||
} | ||
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@Override | ||
public void close() { | ||
if (stream == bytesStreamOutput) { | ||
assert shouldCompress == false : "If the streams are the same we should not be compressing"; | ||
IOUtils.closeWhileHandlingException(stream); | ||
} else { | ||
assert shouldCompress : "If the streams are different we should be compressing"; | ||
IOUtils.closeWhileHandlingException(stream, bytesStreamOutput); | ||
} | ||
} | ||
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@Override | ||
public void reset() throws IOException { | ||
stream.reset(); | ||
} | ||
} |
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core/src/test/java/org/elasticsearch/transport/CompressibleBytesOutputStreamTests.java
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/* | ||
* Licensed to Elasticsearch under one or more contributor | ||
* license agreements. See the NOTICE file distributed with | ||
* this work for additional information regarding copyright | ||
* ownership. Elasticsearch 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. | ||
*/ | ||
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package org.elasticsearch.transport; | ||
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import org.elasticsearch.common.bytes.BytesReference; | ||
import org.elasticsearch.common.compress.CompressorFactory; | ||
import org.elasticsearch.common.io.stream.BytesStream; | ||
import org.elasticsearch.common.io.stream.BytesStreamOutput; | ||
import org.elasticsearch.common.io.stream.StreamInput; | ||
import org.elasticsearch.test.ESTestCase; | ||
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import java.io.EOFException; | ||
import java.io.IOException; | ||
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public class CompressibleBytesOutputStreamTests extends ESTestCase { | ||
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public void testStreamWithoutCompression() throws IOException { | ||
BytesStream bStream = new ZeroOutOnCloseStream(); | ||
CompressibleBytesOutputStream stream = new CompressibleBytesOutputStream(bStream, false); | ||
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byte[] expectedBytes = randomBytes(randomInt(30)); | ||
stream.write(expectedBytes); | ||
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BytesReference bytesRef = stream.materializeBytes(); | ||
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assertFalse(CompressorFactory.COMPRESSOR.isCompressed(bytesRef)); | ||
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StreamInput streamInput = bytesRef.streamInput(); | ||
byte[] actualBytes = new byte[expectedBytes.length]; | ||
streamInput.readBytes(actualBytes, 0, expectedBytes.length); | ||
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assertEquals(-1, streamInput.read()); | ||
assertArrayEquals(expectedBytes, actualBytes); | ||
stream.close(); | ||
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// The bytes should be zeroed out on close | ||
for (byte b : bytesRef.toBytesRef().bytes) { | ||
assertEquals((byte) 0, b); | ||
} | ||
} | ||
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public void testStreamWithCompression() throws IOException { | ||
BytesStream bStream = new ZeroOutOnCloseStream(); | ||
CompressibleBytesOutputStream stream = new CompressibleBytesOutputStream(bStream, true); | ||
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byte[] expectedBytes = randomBytes(randomInt(30)); | ||
stream.write(expectedBytes); | ||
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BytesReference bytesRef = stream.materializeBytes(); | ||
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assertTrue(CompressorFactory.COMPRESSOR.isCompressed(bytesRef)); | ||
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StreamInput streamInput = CompressorFactory.COMPRESSOR.streamInput(bytesRef.streamInput()); | ||
byte[] actualBytes = new byte[expectedBytes.length]; | ||
streamInput.readBytes(actualBytes, 0, expectedBytes.length); | ||
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assertEquals(-1, streamInput.read()); | ||
assertArrayEquals(expectedBytes, actualBytes); | ||
stream.close(); | ||
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// The bytes should be zeroed out on close | ||
for (byte b : bytesRef.toBytesRef().bytes) { | ||
assertEquals((byte) 0, b); | ||
} | ||
} | ||
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public void testCompressionWithCallingMaterializeFails() throws IOException { | ||
BytesStream bStream = new ZeroOutOnCloseStream(); | ||
CompressibleBytesOutputStream stream = new CompressibleBytesOutputStream(bStream, true); | ||
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byte[] expectedBytes = randomBytes(randomInt(30)); | ||
stream.write(expectedBytes); | ||
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StreamInput streamInput = CompressorFactory.COMPRESSOR.streamInput(bStream.bytes().streamInput()); | ||
byte[] actualBytes = new byte[expectedBytes.length]; | ||
EOFException e = expectThrows(EOFException.class, () -> streamInput.readBytes(actualBytes, 0, expectedBytes.length)); | ||
assertEquals("Unexpected end of ZLIB input stream", e.getMessage()); | ||
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stream.close(); | ||
} | ||
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private static byte[] randomBytes(int length) { | ||
byte[] bytes = new byte[length]; | ||
for (int i = 0; i < bytes.length; ++i) { | ||
bytes[i] = randomByte(); | ||
} | ||
return bytes; | ||
} | ||
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private static class ZeroOutOnCloseStream extends BytesStreamOutput { | ||
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@Override | ||
public void close() { | ||
int size = (int) bytes.size(); | ||
bytes.set(0, new byte[size], 0, size); | ||
} | ||
} | ||
} |