content: /*
   * 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.asterix.external.library;
  
  import java.io.IOException;
  import java.lang.invoke.MethodHandle;
  import java.lang.invoke.MethodHandles;
  import java.lang.invoke.MethodType;
  import java.lang.invoke.VarHandle;
  import java.net.ProtocolFamily;
  import java.net.SocketAddress;
  import java.net.StandardProtocolFamily;
  import java.nio.channels.Channels;
  import java.nio.channels.SocketChannel;
  import java.nio.file.Path;
  
  import org.apache.asterix.common.exceptions.AsterixException;
  import org.apache.asterix.common.library.ILibraryManager;
  import org.apache.asterix.external.ipc.PythonDomainSocketProto;
  import org.apache.asterix.om.functions.IExternalFunctionInfo;
  import org.apache.hyracks.api.context.IHyracksTaskContext;
  import org.apache.hyracks.api.dataflow.TaskAttemptId;
  import org.apache.hyracks.api.exceptions.ErrorCode;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.IWarningCollector;
  import org.apache.hyracks.api.exceptions.SourceLocation;
  import org.apache.hyracks.api.job.JobId;
  import org.apache.hyracks.control.common.controllers.NCConfig;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  public class PythonLibraryDomainSocketEvaluator extends AbstractLibrarySocketEvaluator {
  
      private final ILibraryManager libMgr;
      private final Path sockPath;
      SocketChannel chan;
      ProcessHandle pid;
      private static final Logger LOGGER = LogManager.getLogger(ExternalLibraryManager.class);
  
      public PythonLibraryDomainSocketEvaluator(JobId jobId, PythonLibraryEvaluatorId evaluatorId, ILibraryManager libMgr,
              TaskAttemptId task, IWarningCollector warningCollector, SourceLocation sourceLoc, Path sockPath) {
          super(jobId, evaluatorId, task, warningCollector, sourceLoc);
          this.libMgr = libMgr;
          this.sockPath = sockPath;
      }
  
      public void start() throws IOException, AsterixException {
          PythonLibraryEvaluatorId fnId = (PythonLibraryEvaluatorId) id;
          PythonLibrary library = (PythonLibrary) libMgr.getLibrary(fnId.getLibraryNamespace(), fnId.getLibraryName());
          String wd = library.getFile().getAbsolutePath();
          MethodHandles.Lookup lookup = MethodHandles.lookup();
          SocketAddress sockAddr;
          try {
              VarHandle sockEnum = lookup.in(StandardProtocolFamily.class)
                      .findStaticVarHandle(StandardProtocolFamily.class, "UNIX", StandardProtocolFamily.class);
              Class domainSock = Class.forName("java.net.UnixDomainSocketAddress");
              MethodType unixDomainSockAddrType = MethodType.methodType(domainSock, Path.class);
              MethodHandle unixDomainSockAddr = lookup.findStatic(domainSock, "of", unixDomainSockAddrType);
              MethodType sockChanMethodType = MethodType.methodType(SocketChannel.class, ProtocolFamily.class);
              MethodHandle sockChanOpen = lookup.findStatic(SocketChannel.class, "open", sockChanMethodType);
              sockAddr = ((SocketAddress) unixDomainSockAddr.invoke(sockPath));
              chan = (SocketChannel) sockChanOpen.invoke(sockEnum.get());
          } catch (Throwable e) {
              throw HyracksDataException.create(ErrorCode.LOCAL_NETWORK_ERROR, e);
          }
          chan.connect(sockAddr);
          proto = new PythonDomainSocketProto(Channels.newOutputStream(chan), chan, wd);
          proto.start();
          proto.helo();
          this.pid = ((PythonDomainSocketProto) proto).getPid();
      }
  
      @Override
      public void deallocate() {
          try {
              if (proto != null) {
                  proto.quit();
              }
              if (chan != null) {
                  chan.close();
              }
          } catch (IOException e) {
              LOGGER.error("Caught exception exiting Python UDF:", e);
          }
          if (pid != null && pid.isAlive()) {
              LOGGER.error("Python UDF " + pid.pid() + " did not exit as expected.");
          }
      }
  
      static PythonLibraryDomainSocketEvaluator getInstance(IExternalFunctionInfo finfo, ILibraryManager libMgr,
              IHyracksTaskContext ctx, IWarningCollector warningCollector, SourceLocation sourceLoc)
              throws IOException, AsterixException {
          PythonLibraryEvaluatorId evaluatorId = new PythonLibraryEvaluatorId(finfo.getLibraryNamespace(),
                  finfo.getLibraryName(), Thread.currentThread());
          PythonLibraryDomainSocketEvaluator evaluator =
                  (PythonLibraryDomainSocketEvaluator) ctx.getStateObject(evaluatorId);
          if (evaluator == null) {
              Path sockPath = Path.of(ctx.getJobletContext().getServiceContext().getAppConfig()
                      .getString(NCConfig.Option.PYTHON_DS_PATH));
              evaluator = new PythonLibraryDomainSocketEvaluator(ctx.getJobletContext().getJobId(), evaluatorId, libMgr,
                      ctx.getTaskAttemptId(), warningCollector, sourceLoc, sockPath);
              ctx.getJobletContext().registerDeallocatable(evaluator);
              evaluator.start();
              ctx.setStateObject(evaluator);
          }
          return evaluator;
      }
  
  }
  