/*
* Copyright (C) 2012 Facebook, Inc.
*
* Licensed 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 com.facebook.swift.service;
import com.facebook.nifty.core.RequestContext;
import com.facebook.nifty.processor.NiftyProcessor;
import com.facebook.swift.codec.ThriftCodecManager;
import com.facebook.swift.service.metadata.ThriftMethodMetadata;
import com.facebook.swift.service.metadata.ThriftServiceMetadata;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.SettableFuture;
import org.apache.thrift.TApplicationException;
import org.apache.thrift.TException;
import org.apache.thrift.protocol.TMessage;
import org.apache.thrift.protocol.TMessageType;
import org.apache.thrift.protocol.TProtocol;
import org.apache.thrift.protocol.TProtocolUtil;
import org.apache.thrift.protocol.TType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.List;
import java.util.Map;
import javax.annotation.concurrent.ThreadSafe;
import static org.apache.thrift.TApplicationException.INVALID_MESSAGE_TYPE;
import static org.apache.thrift.TApplicationException.UNKNOWN_METHOD;
/**
* Example TProcessor that wraps a Thrift service. This should only be considered an example, and
* is not production ready. For example, this class makes assumptions about the thrift id of
* method parameters, and does not support Thrift exceptions properly.
*/
@ThreadSafe
public class ThriftServiceProcessor implements NiftyProcessor
{
private static final Logger LOG = LoggerFactory.getLogger(ThriftServiceProcessor.class);
private final Map<String, ThriftMethodProcessor> methods;
private final List<ThriftEventHandler> eventHandlers;
/**
* @param eventHandlers event handlers to attach to services
* @param services the services to expose; services must be thread safe
*/
public ThriftServiceProcessor(ThriftCodecManager codecManager, List<? extends ThriftEventHandler> eventHandlers, Object... services)
{
this(codecManager, eventHandlers, ImmutableList.copyOf(services));
}
public ThriftServiceProcessor(ThriftCodecManager codecManager, List<? extends ThriftEventHandler> eventHandlers, List<?> services)
{
Preconditions.checkNotNull(codecManager, "codecManager is null");
Preconditions.checkNotNull(services, "service is null");
Preconditions.checkArgument(!services.isEmpty(), "services is empty");
// NOTE: ImmutableMap enforces that we don't have duplicate method names
ImmutableMap.Builder<String, ThriftMethodProcessor> processorBuilder = ImmutableMap.builder();
for (Object service : services) {
ThriftServiceMetadata serviceMetadata = new ThriftServiceMetadata(service.getClass(), codecManager.getCatalog());
for (ThriftMethodMetadata methodMetadata : serviceMetadata.getMethods().values()) {
ThriftMethodProcessor methodProcessor = new ThriftMethodProcessor(service,
serviceMetadata.getName(), methodMetadata, codecManager);
processorBuilder.put(methodMetadata.getName(), methodProcessor);
}
}
methods = processorBuilder.build();
this.eventHandlers = ImmutableList.copyOf(eventHandlers);
}
public Map<String, ThriftMethodProcessor> getMethods()
{
return methods;
}
@Override
@SuppressWarnings("PMD.EmptyCatchBlock")
public ListenableFuture<Boolean> process(final TProtocol in, TProtocol out, RequestContext requestContext)
throws TException
{
try {
final SettableFuture<Boolean> resultFuture = SettableFuture.create();
TMessage message = in.readMessageBegin();
String methodName = message.name;
int sequenceId = message.seqid;
// lookup method
ThriftMethodProcessor method = methods.get(methodName);
if (method == null) {
TProtocolUtil.skip(in, TType.STRUCT);
writeApplicationException(out, methodName, sequenceId, UNKNOWN_METHOD, "Invalid method name: '" + methodName + "'", null);
return Futures.immediateFuture(true);
}
switch (message.type) {
case TMessageType.CALL:
case TMessageType.ONEWAY:
// Ideally we'd check the message type here to make the presence/absence of
// the "oneway" keyword annotating the method matches the message type.
// Unfortunately most clients send both one-way and two-way messages as CALL
// message type instead of using ONEWAY message type, and servers ignore the
// difference.
break;
default:
TProtocolUtil.skip(in, TType.STRUCT);
writeApplicationException(out, methodName, sequenceId, INVALID_MESSAGE_TYPE, "Received invalid message type " + message.type + " from client", null);
return Futures.immediateFuture(true);
}
// invoke method
final ContextChain context = new ContextChain(eventHandlers, method.getQualifiedName(), requestContext);
ListenableFuture<Boolean> processResult = method.process(in, out, sequenceId, context);
Futures.addCallback(
processResult,
new FutureCallback<Boolean>()
{
@Override
public void onSuccess(Boolean result)
{
context.done();
resultFuture.set(result);
}
@Override
public void onFailure(Throwable t)
{
context.done();
resultFuture.setException(t);
}
});
return resultFuture;
}
catch (Exception e) {
return Futures.immediateFailedFuture(e);
}
}
public static TApplicationException writeApplicationException(
TProtocol outputProtocol,
String methodName,
int sequenceId,
int errorCode,
String errorMessage,
Throwable cause)
throws TException
{
// unexpected exception
TApplicationException applicationException = new TApplicationException(errorCode, errorMessage);
if (cause != null) {
applicationException.initCause(cause);
}
LOG.error(errorMessage, applicationException);
// Application exceptions are sent to client, and the connection can be reused
outputProtocol.writeMessageBegin(new TMessage(methodName, TMessageType.EXCEPTION, sequenceId));
applicationException.write(outputProtocol);
outputProtocol.writeMessageEnd();
outputProtocol.getTransport().flush();
return applicationException;
}
}