| /** |
| * 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.avro.ipc; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.avro.AvroRuntimeException; |
| import org.apache.avro.UnresolvedUnionException; |
| import org.apache.avro.Protocol; |
| import org.apache.avro.Schema; |
| import org.apache.avro.Protocol.Message; |
| import org.apache.avro.util.ByteBufferInputStream; |
| import org.apache.avro.util.ByteBufferOutputStream; |
| import org.apache.avro.util.Utf8; |
| import org.apache.avro.generic.GenericDatumReader; |
| import org.apache.avro.generic.GenericDatumWriter; |
| import org.apache.avro.io.DecoderFactory; |
| import org.apache.avro.io.BinaryEncoder; |
| import org.apache.avro.io.Decoder; |
| import org.apache.avro.io.Encoder; |
| import org.apache.avro.io.EncoderFactory; |
| import org.apache.avro.specific.SpecificDatumReader; |
| import org.apache.avro.specific.SpecificDatumWriter; |
| |
| /** Base class for the server side of a protocol interaction. */ |
| public abstract class Responder { |
| private static final Logger LOG = LoggerFactory.getLogger(Responder.class); |
| |
| private static final Schema META = |
| Schema.createMap(Schema.create(Schema.Type.BYTES)); |
| private static final GenericDatumReader<Map<CharSequence,ByteBuffer>> |
| META_READER = new GenericDatumReader<Map<CharSequence,ByteBuffer>>(META); |
| private static final GenericDatumWriter<Map<CharSequence,ByteBuffer>> |
| META_WRITER = new GenericDatumWriter<Map<CharSequence,ByteBuffer>>(META); |
| |
| private static final ThreadLocal<Protocol> REMOTE = |
| new ThreadLocal<Protocol>(); |
| |
| private Map<MD5,Protocol> protocols |
| = Collections.synchronizedMap(new HashMap<MD5,Protocol>()); |
| |
| private Protocol local; |
| private MD5 localHash; |
| protected List<RPCPlugin> rpcMetaPlugins; |
| |
| protected Responder(Protocol local) { |
| this.local = local; |
| this.localHash = new MD5(); |
| localHash.bytes(local.getMD5()); |
| protocols.put(localHash, local); |
| this.rpcMetaPlugins = |
| Collections.synchronizedList(new ArrayList<RPCPlugin>()); |
| } |
| |
| /** Return the remote protocol. Accesses a {@link ThreadLocal} that's set |
| * around calls to {@link #respond(Protocol.Message, Object)}. */ |
| public static Protocol getRemote() { return REMOTE.get(); } |
| |
| /** Return the local protocol. */ |
| public Protocol getLocal() { return local; } |
| |
| /** |
| * Adds a new plugin to manipulate per-call metadata. Plugins |
| * are executed in the order that they are added. |
| * @param plugin a plugin that will manipulate RPC metadata |
| */ |
| public void addRPCPlugin(RPCPlugin plugin) { |
| rpcMetaPlugins.add(plugin); |
| } |
| |
| /** Called by a server to deserialize a request, compute and serialize |
| * a response or error. */ |
| public List<ByteBuffer> respond(List<ByteBuffer> buffers) throws IOException { |
| return respond(buffers, null); |
| } |
| |
| /** Called by a server to deserialize a request, compute and serialize a |
| * response or error. Transciever is used by connection-based servers to |
| * track handshake status of connection. */ |
| public List<ByteBuffer> respond(List<ByteBuffer> buffers, |
| Transceiver connection) throws IOException { |
| Decoder in = DecoderFactory.get().binaryDecoder( |
| new ByteBufferInputStream(buffers), null); |
| ByteBufferOutputStream bbo = new ByteBufferOutputStream(); |
| BinaryEncoder out = EncoderFactory.get().binaryEncoder(bbo, null); |
| Exception error = null; |
| RPCContext context = new RPCContext(); |
| List<ByteBuffer> payload = null; |
| List<ByteBuffer> handshake = null; |
| boolean wasConnected = connection != null && connection.isConnected(); |
| try { |
| Protocol remote = handshake(in, out, connection); |
| out.flush(); |
| if (remote == null) // handshake failed |
| return bbo.getBufferList(); |
| handshake = bbo.getBufferList(); |
| |
| // read request using remote protocol specification |
| context.setRequestCallMeta(META_READER.read(null, in)); |
| String messageName = in.readString(null).toString(); |
| Message rm = remote.getMessages().get(messageName); |
| if (rm == null) |
| throw new AvroRuntimeException("No such remote message: "+messageName); |
| Message m = getLocal().getMessages().get(messageName); |
| if (m == null) |
| throw new AvroRuntimeException("No message named "+messageName |
| +" in "+getLocal()); |
| |
| Object request = readRequest(rm.getRequest(), m.getRequest(), in); |
| |
| context.setMessage(rm); |
| for (RPCPlugin plugin : rpcMetaPlugins) { |
| plugin.serverReceiveRequest(context); |
| } |
| |
| // create response using local protocol specification |
| if ((m.isOneWay() != rm.isOneWay()) && wasConnected) |
| throw new AvroRuntimeException("Not both one-way: "+messageName); |
| |
| Object response = null; |
| |
| try { |
| REMOTE.set(remote); |
| response = respond(m, request); |
| context.setResponse(response); |
| } catch (Exception e) { |
| error = e; |
| context.setError(error); |
| LOG.warn("user error", e); |
| } finally { |
| REMOTE.set(null); |
| } |
| |
| if (m.isOneWay() && wasConnected) // no response data |
| return null; |
| |
| out.writeBoolean(error != null); |
| if (error == null) |
| writeResponse(m.getResponse(), response, out); |
| else |
| try { |
| writeError(m.getErrors(), error, out); |
| } catch (UnresolvedUnionException e) { // unexpected error |
| throw error; |
| } |
| } catch (Exception e) { // system error |
| LOG.warn("system error", e); |
| context.setError(e); |
| bbo = new ByteBufferOutputStream(); |
| out = EncoderFactory.get().binaryEncoder(bbo, null); |
| out.writeBoolean(true); |
| writeError(Protocol.SYSTEM_ERRORS, new Utf8(e.toString()), out); |
| if (null == handshake) { |
| handshake = new ByteBufferOutputStream().getBufferList(); |
| } |
| } |
| out.flush(); |
| payload = bbo.getBufferList(); |
| |
| // Grab meta-data from plugins |
| context.setResponsePayload(payload); |
| for (RPCPlugin plugin : rpcMetaPlugins) { |
| plugin.serverSendResponse(context); |
| } |
| META_WRITER.write(context.responseCallMeta(), out); |
| out.flush(); |
| // Prepend handshake and append payload |
| bbo.prepend(handshake); |
| bbo.append(payload); |
| |
| return bbo.getBufferList(); |
| } |
| |
| private SpecificDatumWriter<HandshakeResponse> handshakeWriter = |
| new SpecificDatumWriter<HandshakeResponse>(HandshakeResponse.class); |
| private SpecificDatumReader<HandshakeRequest> handshakeReader = |
| new SpecificDatumReader<HandshakeRequest>(HandshakeRequest.class); |
| |
| private Protocol handshake(Decoder in, Encoder out, Transceiver connection) |
| throws IOException { |
| if (connection != null && connection.isConnected()) |
| return connection.getRemote(); |
| HandshakeRequest request = (HandshakeRequest)handshakeReader.read(null, in); |
| Protocol remote = protocols.get(request.clientHash); |
| if (remote == null && request.clientProtocol != null) { |
| remote = Protocol.parse(request.clientProtocol.toString()); |
| protocols.put(request.clientHash, remote); |
| } |
| HandshakeResponse response = new HandshakeResponse(); |
| if (localHash.equals(request.serverHash)) { |
| response.match = |
| remote == null ? HandshakeMatch.NONE : HandshakeMatch.BOTH; |
| } else { |
| response.match = |
| remote == null ? HandshakeMatch.NONE : HandshakeMatch.CLIENT; |
| } |
| if (response.match != HandshakeMatch.BOTH) { |
| response.serverProtocol = new Utf8(local.toString()); |
| response.serverHash = localHash; |
| } |
| |
| RPCContext context = new RPCContext(); |
| context.setHandshakeRequest(request); |
| context.setHandshakeResponse(response); |
| for (RPCPlugin plugin : rpcMetaPlugins) { |
| plugin.serverConnecting(context); |
| } |
| handshakeWriter.write(response, out); |
| |
| if (connection != null && response.match != HandshakeMatch.NONE) |
| connection.setRemote(remote); |
| |
| return remote; |
| } |
| |
| /** Computes the response for a message. */ |
| public abstract Object respond(Message message, Object request) |
| throws Exception; |
| |
| /** Reads a request message. */ |
| public abstract Object readRequest(Schema actual, Schema expected, Decoder in) |
| throws IOException; |
| |
| /** Writes a response message. */ |
| public abstract void writeResponse(Schema schema, Object response, |
| Encoder out) throws IOException; |
| |
| /** Writes an error message. */ |
| public abstract void writeError(Schema schema, Object error, |
| Encoder out) throws IOException; |
| |
| } |
| |