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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.ipc;
import java.io.Closeable;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import javax.net.SocketFactory;
import org.apache.avro.ipc.Responder;
import org.apache.avro.ipc.Transceiver;
import org.apache.avro.ipc.reflect.ReflectRequestor;
import org.apache.avro.ipc.reflect.ReflectResponder;
import org.apache.avro.ipc.specific.SpecificRequestor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.token.SecretManager;
import org.apache.hadoop.security.token.TokenIdentifier;
/** Tunnel Avro-format RPC requests over a Hadoop {@link RPC} connection. This
* does not give cross-language wire compatibility, since the Hadoop RPC wire
* format is non-standard, but it does permit use of Avro's protocol versioning
* features for inter-Java RPCs. */
@InterfaceStability.Evolving
public class AvroRpcEngine implements RpcEngine {
private static final Log LOG = LogFactory.getLog(RPC.class);
private static int VERSION = 0;
// the implementation we tunnel through
private static final RpcEngine ENGINE = new WritableRpcEngine();
/** Tunnel an Avro RPC request and response through Hadoop's RPC. */
private static interface TunnelProtocol extends VersionedProtocol {
/** All Avro methods and responses go through this. */
BufferListWritable call(BufferListWritable request) throws IOException;
}
/** A Writable that holds a List, The Avro RPC Transceiver's
* basic unit of data transfer.*/
private static class BufferListWritable implements Writable {
private List buffers;
public BufferListWritable() {} // required for RPC Writables
public BufferListWritable(List buffers) {
this.buffers = buffers;
}
public void readFields(DataInput in) throws IOException {
int size = in.readInt();
buffers = new ArrayList(size);
for (int i = 0; i < size; i++) {
int length = in.readInt();
ByteBuffer buffer = ByteBuffer.allocate(length);
in.readFully(buffer.array(), 0, length);
buffers.add(buffer);
}
}
public void write(DataOutput out) throws IOException {
out.writeInt(buffers.size());
for (ByteBuffer buffer : buffers) {
out.writeInt(buffer.remaining());
out.write(buffer.array(), buffer.position(), buffer.remaining());
}
}
}
/** An Avro RPC Transceiver that tunnels client requests through Hadoop
* RPC. */
private static class ClientTransceiver extends Transceiver {
private TunnelProtocol tunnel;
private InetSocketAddress remote;
public ClientTransceiver(InetSocketAddress addr,
UserGroupInformation ticket,
Configuration conf, SocketFactory factory,
int rpcTimeout)
throws IOException {
this.tunnel =
(TunnelProtocol)ENGINE.getProxy(TunnelProtocol.class, VERSION,
addr, ticket, conf, factory,
rpcTimeout);
this.remote = addr;
}
public String getRemoteName() { return remote.toString(); }
public List transceive(List request)
throws IOException {
return tunnel.call(new BufferListWritable(request)).buffers;
}
public List readBuffers() throws IOException {
throw new UnsupportedOperationException();
}
public void writeBuffers(List buffers) throws IOException {
throw new UnsupportedOperationException();
}
public void close() throws IOException {
ENGINE.stopProxy(tunnel);
}
}
/** Construct a client-side proxy object that implements the named protocol,
* talking to a server at the named address. */
public Object getProxy(Class protocol, long clientVersion,
InetSocketAddress addr, UserGroupInformation ticket,
Configuration conf, SocketFactory factory,
int rpcTimeout)
throws IOException {
return Proxy.newProxyInstance
(protocol.getClassLoader(),
new Class[] { protocol },
new Invoker(protocol, addr, ticket, conf, factory, rpcTimeout));
}
/** Stop this proxy. */
public void stopProxy(Object proxy) {
try {
((Invoker)Proxy.getInvocationHandler(proxy)).close();
} catch (IOException e) {
LOG.warn("Error while stopping "+proxy, e);
}
}
private class Invoker implements InvocationHandler, Closeable {
private final ClientTransceiver tx;
private final SpecificRequestor requestor;
public Invoker(Class protocol, InetSocketAddress addr,
UserGroupInformation ticket, Configuration conf,
SocketFactory factory,
int rpcTimeout) throws IOException {
this.tx = new ClientTransceiver(addr, ticket, conf, factory, rpcTimeout);
this.requestor = createRequestor(protocol, tx);
}
@Override public Object invoke(Object proxy, Method method, Object[] args)
throws Throwable {
return requestor.invoke(proxy, method, args);
}
public void close() throws IOException {
tx.close();
}
}
protected SpecificRequestor createRequestor(Class protocol,
Transceiver transeiver) throws IOException {
return new ReflectRequestor(protocol, transeiver);
}
protected Responder createResponder(Class iface, Object impl) {
return new ReflectResponder(iface, impl);
}
/** An Avro RPC Responder that can process requests passed via Hadoop RPC. */
private class TunnelResponder implements TunnelProtocol {
private Responder responder;
public TunnelResponder(Class iface, Object impl) {
responder = createResponder(iface, impl);
}
public long getProtocolVersion(String protocol, long version)
throws IOException {
return VERSION;
}
public BufferListWritable call(final BufferListWritable request)
throws IOException {
return new BufferListWritable(responder.respond(request.buffers));
}
}
public Object[] call(Method method, Object[][] params,
InetSocketAddress[] addrs, UserGroupInformation ticket,
Configuration conf) throws IOException {
throw new UnsupportedOperationException();
}
/** Construct a server for a protocol implementation instance listening on a
* port and address. */
public RPC.Server getServer(Class iface, Object impl, String bindAddress,
int port, int numHandlers, boolean verbose,
Configuration conf,
SecretManager secretManager
) throws IOException {
return ENGINE.getServer(TunnelProtocol.class,
new TunnelResponder(iface, impl),
bindAddress, port, numHandlers, verbose, conf,
secretManager);
}
}