README.md

Avro Netty ByteBuf Encoder/Decoder

Simple Apache Avro Encoder/Decoder implemented using netty.io byte buffers ( io.netty.buffer.ByteBuf ). The main motivation for this implementation is to utilize Netty's powerful ButeBuf pooling.

How to use?

To use Encoder just create new instance:

// GenericRecord record - record to encode 
final ByteBuf buffer = ByteBufAllocator.DEFAULT.buffer(1024);
final ByteBufEncoder encoder = new ByteBufEncoder();
encoder.setBuffer(buffer); // buffer to be used to store serialized object 
final DatumWriter<GenericRecord> writer = new GenericDatumWriter<GenericRecord>(record.getSchema());

try {
    writer.write(record, encoder);
    final ByteBuf result = encoder.getBuffer(); // return the buffer with the serialized object
	// do something with result, but don't forget to release it 
} catch (final Exception e) {
    throw new RuntimeException(e);
} 

Decoder has similar api:

// ByteBuf buffer - buffer to decode
final ByteBufDecoder decoder = new ByteBufDecoder();
decoder.setBuffer(buffer);
final GenericDatumReader<GenericRecord> reader = new GenericDatumReader<GenericRecord>(record.getSchema());
try {
    final GenericRecord record = reader.read(null, decoder);
    // do something with record
} catch (final IOException e) {
    throw new RuntimeException(e);
}

Encoder/Decoder Note

To get best performance from decoder don't forget to use pooled buffers and turn leak detection off!

$java -Dio.netty.leakDetectionLevel=DISABLED -Dio.netty.allocator.type=pooled  ...

Encoder/Decoder is not thread safe, developer should ensure thread safety if needed.

NettyGenericDatumWriter

Default DatumWriter implementation GenericDatumWriter expects java.nio.ByteBuffer for byte array properties, which may not be optimal for all use cases especially if powerful netty pooled buffer allocator is used. NettyGenericDatumWriter has ability to write io.netty.buffer.ByteBuf if used for byte array properties.

byte[] value = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
final GenericRecord record = new GenericData.Record(E_BYTES.SCHEMA$);
// use ByteBuf for byte array propertie
record.put("f_value", ByteBufAllocator.DEFAULT.buffer(value.length).writeBytes(value));

final ByteBuf buffer = ByteBufAllocator.DEFAULT.buffer(64);
final ByteBufEncoder encoder = new ByteBufEncoder();
encoder.setBuffer(buffer);

final DatumWriter<GenericRecord> writer = new NettyGenericDatumWriter<GenericRecord>(record.getSchema());
writer.write(record, encoder);

Note that if you use ByteBuf as a generic record property you'll have to release it manually, NettyGenericDatumWriter wont release it for you.

schema used:

{"namespace": "com.github.milenkovicm.avro.test.event",
 "type": "record",
 "name": "E_BYTES",     
  "fields": [
 
      {"name": "f_value",   "type": "bytes"}
      ]
}

NettyGenericDatumReader

Default DatumReader implementation GenericDatumReader uses java.nio.ByteBuffer for byte array properties, which may not be optimal for all use cases especially if powerful netty pooled buffer allocator is used. NettyGenericDatumReader has ability to read byte arrays as io.netty.buffer.ByteBuf. Be careful as ByteBuf properties should be released when not needed.

final ByteBufDecoder decoder = new ByteBufDecoder();
decoder.setBuffer(buffer);
final GenericDatumReader<GenericRecord> reader = new NettyGenericDatumReader<GenericRecord>(schema);
GenericRecord record =  reader.read(null, decoder);

Don't forget!

Don't forget two things:

1. to release ByteBuf when not needed anymore.
2. implementations are not thread safe.

that's it!