/*
    * 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.hadoop.hbase.util;
  
  import java.io.IOException;
  import java.lang.management.ManagementFactory;
  import java.util.List;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  
  /**
   * Process related utilities.
   */
  @InterfaceAudience.Private
  public final class ProcessUtils {
    private static Log LOG = LogFactory.getLog(ProcessUtils.class);
  
    private ProcessUtils() { }
  
    public static Integer getPid() {
      // JVM_PID is exported by bin/hbase run script
      String pidStr = System.getenv("JVM_PID");
  
      // in case if it is not set correctly used fallback from mxbean which is implementation specific
      if (pidStr == null || pidStr.trim().isEmpty()) {
        String name = ManagementFactory.getRuntimeMXBean().getName();
        if (name != null) {
          int idx = name.indexOf("@");
          if (idx != -1) {
            pidStr = name.substring(0, name.indexOf("@"));
          }
        }
      }
      try {
        if (pidStr != null) {
          return Integer.valueOf(pidStr);
        }
      } catch (NumberFormatException nfe) {
        // ignore
      }
      return null;
    }
  
    public static Process runCmdAsync(List<String> cmd) {
      try {
        LOG.info("Running command async: " + cmd);
        return new ProcessBuilder(cmd).inheritIO().start();
      } catch (IOException ex) {
        throw new IllegalStateException(ex);
      }
    }
  }