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.kafka.trogdor.fault;
  
  import org.apache.kafka.common.internals.KafkaFutureImpl;
  import org.apache.kafka.trogdor.common.Platform;
  import org.apache.kafka.trogdor.task.TaskWorker;
  import org.apache.kafka.trogdor.task.WorkerStatusTracker;
  
  import com.fasterxml.jackson.databind.node.TextNode;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.stream.Collectors;
  
  public class ProcessStopFaultWorker implements TaskWorker {
      private static final Logger log = LoggerFactory.getLogger(ProcessStopFaultWorker.class);
  
      private final String id;
  
      private final String javaProcessName;
  
      private WorkerStatusTracker status;
  
      public ProcessStopFaultWorker(String id, String javaProcessName) {
          this.id = id;
          this.javaProcessName = javaProcessName;
      }
  
      @Override
      public void start(Platform platform, WorkerStatusTracker status,
                        KafkaFutureImpl<String> errorFuture) throws Exception {
          this.status = status;
          log.info("Activating ProcessStopFault {}.", id);
          this.status.update(new TextNode("stopping " + javaProcessName));
          sendSignals(platform, "SIGSTOP");
          this.status.update(new TextNode("stopped " + javaProcessName));
      }
  
      @Override
      public void stop(Platform platform) throws Exception {
          log.info("Deactivating ProcessStopFault {}.", id);
          this.status.update(new TextNode("resuming " + javaProcessName));
          sendSignals(platform, "SIGCONT");
          this.status.update(new TextNode("resumed " + javaProcessName));
      }
  
      private void sendSignals(Platform platform, String signalName) throws Exception {
          String jcmdOutput = platform.runCommand(new String[] {"jcmd"});
          String[] lines = jcmdOutput.split("\n");
          List<Integer> pids = new ArrayList<>();
          for (String line : lines) {
              if (line.contains(javaProcessName)) {
                  String[] components = line.split(" ");
                  try {
                      pids.add(Integer.parseInt(components[0]));
                  } catch (NumberFormatException e) {
                      log.error("Failed to parse process ID from line", e);
                  }
              }
          }
          if (pids.isEmpty()) {
              log.error("{}: no processes containing {} found to send {} to.",
                  id, javaProcessName, signalName);
          } else {
              log.info("{}: sending {} to {} pid(s) {}",
                  id, signalName, javaProcessName, pids.stream().map(Object::toString).collect(Collectors.joining(",")));
              for (Integer pid : pids) {
                  platform.runCommand(new String[] {"kill", "-" + signalName, pid.toString()});
              }
          }
      }
  }
  