me.tfeng.playmods.avro.d2.AvroD2ProtocolVersionResolver Maven / Gradle / Ivy

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/**
 * Copyright 2016 Thomas Feng
 *
 * 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 me.tfeng.playmods.avro.d2;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

import javax.xml.bind.DatatypeConverter;

import org.apache.avro.Protocol;
import org.apache.avro.io.Decoder;
import org.apache.avro.io.Encoder;
import org.apache.avro.ipc.HandshakeMatch;
import org.apache.avro.ipc.HandshakeRequest;
import org.apache.avro.ipc.HandshakeResponse;
import org.apache.avro.ipc.MD5;
import org.apache.avro.ipc.RPCContext;
import org.apache.avro.ipc.Responder;
import org.apache.avro.ipc.Transceiver;
import org.apache.zookeeper.KeeperException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.Maps;

import me.tfeng.playmods.avro.AvroConstants;
import me.tfeng.playmods.avro.ProtocolVersionResolver;
import play.Logger;
import play.Logger.ALogger;

/**
 * @author Thomas Feng ([email protected])
 */
@Component("play-mods.avro-d2.protocol-version-resolver")
public class AvroD2ProtocolVersionResolver implements ProtocolVersionResolver {

  private static final ALogger LOG = Logger.of(AvroD2ProtocolVersionResolver.class);

  @Autowired
  @Qualifier("play-mods.avro-d2.component")
  private AvroD2Component avroD2Component;

  private final Map, Protocol> protocolCache = Maps.newHashMap();

  @Override
  public Protocol resolve(Responder responder, Decoder in, Encoder out, Transceiver connection) throws IOException {
    Protocol serverProtocol = responder.getLocal();
    byte[] serverMD5 = serverProtocol.getMD5();
    String namespace = serverProtocol.getNamespace();
    String name = serverProtocol.getName();
    HandshakeRequest request = AvroConstants.HANDSHAKE_REQUEST_READER.read(null, in);
    MD5 clientHash = request.getClientHash();
    HandshakeResponse response = new HandshakeResponse();
    Protocol protocol = null;
    if (clientHash == null) {
      LOG.error("Client protocol MD5 is missing from request (namespace=" + namespace + ", name=" + name + ")");
    } else {
      byte[] clientMD5 = clientHash.bytes();
      if (Arrays.equals(clientMD5, serverMD5)) {
        protocol = serverProtocol;
        response.setMatch(HandshakeMatch.BOTH);
      } else {
        String clientMD5String = DatatypeConverter.printHexBinary(clientMD5);
        protocol = getProtocol(namespace, name, clientMD5String);
        if (protocol == null) {
          try {
            protocol = AvroD2Helper.readProtocolFromZk(avroD2Component.getZooKeeper(), namespace, name,
                clientMD5String);
            response.setMatch(HandshakeMatch.CLIENT);
            setProtocol(namespace, name, clientMD5String, protocol);
          } catch (InterruptedException | KeeperException e) {
            LOG.error("Unable to read schema from ZooKeeper for protocol (namespace=" + namespace + ", name=" + name
                + ", MD5=" + clientMD5String + ")", e);
          }
        } else {
          response.setMatch(HandshakeMatch.CLIENT);
        }
      }
    }

    if (protocol == null) {
      response.setMatch(HandshakeMatch.NONE);
    }

    if (response.getMatch() != HandshakeMatch.BOTH) {
      // Do not return the server protocol, because it is already in ZooKeeper.
      // See AvroD2ResponseProcessor.
      // response.setServerProtocol(serverProtocol.toString());
      response.setServerHash(new MD5(serverMD5));
    }

    RPCContext context = new RPCContext();
    context.setHandshakeRequest(request);
    context.setHandshakeResponse(response);
    AvroConstants.HANDSHAKE_RESPONSE_WRITER.write(response, out);

    return protocol;
  }

  private synchronized Protocol getProtocol(String namespace, String name, String md5) {
    return protocolCache.get(ImmutableList.of(namespace, name, md5));
  }

  private synchronized Protocol setProtocol(String namespace, String name, String md5, Protocol protocol) {
    return protocolCache.put(ImmutableList.of(namespace, name, md5), protocol);
  }
}