#!/usr/bin/env bash
#/**
# *(C) Copyright 2014 Hewlett-Packard Development Company, L.P.
# *
# * Licensed 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.
# */
#
# Run a shell command on all backup master hosts.
#
# Environment Variables
#
#   DCS_BACKUP_MASTERS File naming remote hosts.
#     Default is ${DCS_CONF_DIR}/backup-masters
#   DCS_CONF_DIR  Alternate Dcs conf dir. Default is ${DCS_HOME}/conf.
#   DCS_SLAVE_SLEEP Seconds to sleep between spawning remote commands.
#   DCS_SSH_OPTS Options passed to ssh when running remote commands.
#
# Modelled after $HADOOP_HOME/bin/slaves.sh.

usage="Usage: $0 [--config <dcs-confdir>] command..."

# if no args specified, show usage
if [ $# -le 0 ]; then
  echo $usage
  exit 1
fi

bin=`dirname "${BASH_SOURCE-$0}"`
bin=`cd "$bin">/dev/null; pwd`

. "$bin"/dcs-config.sh

# If the master backup file is specified in the command line,
# then it takes precedence over the definition in 
# dcs-env.sh. Save it here.
HOSTLIST=$DCS_BACKUP_MASTERS

if [ "$HOSTLIST" = "" ]; then
  if [ "$DCS_BACKUP_MASTERS" = "" ]; then
    export HOSTLIST="${DCS_CONF_DIR}/backup-masters"
  else
    export HOSTLIST="${DCS_BACKUP_MASTERS}"
  fi
fi


args=${@// /\\ }
args=${args/master-backup/master}

instance=2

if [ -f $HOSTLIST ]; then
  while read master
  do
    if [ "$master" == "localhost" ] || [ "$master" == "$HOSTNAME" ] ; then
      eval $"$args $instance" 2>&1 | sed "s/^/$master: /" &
    else
      if ${DCS_SLAVE_PARALLEL:-true}; then
        ssh -n $DCS_SSH_OPTS $master $"$args $instance"\
          2>&1 | sed "s/^/$master: /" &
      else # run each command serially
        ssh -n $DCS_SSH_OPTS $master $"$args $instance" \
          2>&1 | sed "s/^/$master: /" &
      fi
    fi
  
    if [ "$DCS_SLAVE_SLEEP" != "" ]; then
      sleep $DCS_SLAVE_SLEEP
    fi
  
    let instance++

  done < "$HOSTLIST"
fi

wait