#!/bin/bash
#
# (c) Copyright 2011 Cloudera, Inc.
#
# init script for the Cloudera SCM Server.
#
# chkconfig: 2345 90 10
# description: Cloudera SCM Server.

### BEGIN INIT INFO
# Provides: cloudera-scm-server
# Required-Start: $local_fs $network $remote_fs $syslog +cloudera-scm-server-db +mysql +postgresql
# Should-Start:
# Required-Stop:
# Default-Start: 3 4 5
# Default-Stop: 0 1 2 6
# Short-Description: Cloudera SCM Server
# Description: Cloudera SCM Server
### END INIT INFO

# Lockable script
LOCKFILE="/tmp/$(basename $0).lock"
LOCKFD=99

lock() {
  flock -$1 $LOCKFD;
}

unlock() {
  lock u;
}

no_more_locking() {
  unlock;
  lock xn && rm -f $LOCKFILE;
}

prepare_locking() {
  eval "exec $LOCKFD>\"$LOCKFILE\"";
  trap no_more_locking EXIT;
}

# Obtain an exclusive lock immediately or fail
exlock_now() {
  lock xn;
}

# Error handling on lock acquisition failure
lock_failure_handler() {
  echo "This script is being executed in another terminal. Exit."
  exit 1
}

# Source function library.
if [ -f /etc/rc.d/init.d/functions ]; then
  . /etc/rc.d/init.d/functions
elif [ -f /lib/lsb/init-functions ]; then
  . /lib/lsb/init-functions
  . /etc/rc.status
  rc_reset
fi

prepare_locking
exlock_now || lock_failure_handler

prog="cloudera-scm-server"
start_timeout=5
kill_timeout=5

# Source defaults file.
CMF_DEFAULTS=$(readlink -e $(dirname ${BASH_SOURCE-$0})/../default)
CMF_DEFAULTS=${CMF_DEFAULTS:-/etc/default}

[ -e $CMF_DEFAULTS/$prog ] && . $CMF_DEFAULTS/$prog

# Paths to configuration, binaries, etc
SERVER_SCRIPT=${CMF_SBINDIR:-/usr/sbin}/cmf-server

SERVER_OUT="${CMF_VAR:-/var}/log/$prog/$prog.out"
USER=cloudera-scm
GROUP=cloudera-scm
MAX_PERMGEN=256
MAX_HEAP=2048

CMF_SUDO_CMD=${CMF_SUDO_CMD:-"su $USER -s"}

# The binary to pass to checkpid and killproc on SuSE
# depends on whether a CMF_SUDO_CMD was used. If not,
# then the real binary is passed, otherwise it has
# to be the CMF_SUDO_CMD binary.
if [ "$CMF_SUDO_CMD" = " " ]; then
  binary="java"
else
  binary=$(echo $CMF_SUDO_CMD | cut -d ' ' -f 1)
fi

if [ ! -f $SERVER_SCRIPT ]; then
  echo "File not found: $SERVER_SCRIPT"
  exit 1
fi

#pid file
pidfile=${PIDFILE-${CMF_VAR:-/var}/run/$prog.pid}

forcefile=${CMF_VAR:-/var}/run/$prog/force_next_start

is_suse=`[ -e /etc/SuSE-release ] && echo 1 || echo 0`

is_systemd=`pstree -p | head -1 | grep 'systemd(1)' -q && echo 1 || echo 0`

RETVAL=0

# Check if a given process (based on the pidfile) is running.
# Return 0 if the process is running, other value if not.
local_checkpid() {
  if [ ! -f $pidfile ]; then
    return 1
  fi

  if [ $is_suse -eq 1 ]; then
    pidofproc -p $pidfile $binary > /dev/null
  else
    checkpid `cat $pidfile`
  fi

  RETVAL=$?
  if [ $RETVAL != 0 ]; then
    ps ax | awk '{print $1}' | grep -Fx `cat $pidfile` > /dev/null
    if [ $? = 1 ]; then
      return $RETVAL;
    else
      return 0
    fi
  fi
  return 0
}

local_killproc() {
  local pid=`cat $pidfile`

  if [ $is_suse -eq 1 ]; then
    killproc -t $kill_timeout -p $pidfile $binary
  else
    killproc -p $pidfile -d $kill_timeout $prog
  fi
  RETVAL=$?
  if [ $RETVAL == 0 ]; then
    ps ax | awk '{print $1}' | grep -Fx $pid > /dev/null
    if [ $? = 1 ]; then
      return 0
    else
      echo $pid > $pidfile
      return 1
    fi
  fi
  return $RETVAL
}

local_check_start() {
  if [ $is_suse -eq 1 ]; then
    local_checkpid && log_success_msg || log_failure_msg
  else
    local_checkpid && echo_success || echo_failure
  fi
  return $RETVAL
}

local_print_stop() {
  if [ $is_suse -eq 1 ]; then
    [ $RETVAL = 0 ] && log_success_msg || log_failure_msg
  else
    # killproc prints on Redhat.
    echo
  fi
}

local_check_success() {
  if [ $is_suse -eq 1 ]; then
    [ $RETVAL = 0 ] && log_success_msg || log_failure_msg
  else
    [ $RETVAL = 0 ] && echo_success || echo_failure
  fi
}

# This method is used to check if the JVM Max Heap or PermGen space is above
# the minimum limit for the SCM server. Each release we perf test SCM and change
# the minimum requirement if needed. This check ensures that we emit an error
# message if customers are running with a lower memory setting. We then exit
# and don't start CM server, letting user fix the issues instead of continuing
# with a broken configuration.
#
# param 1: regex to use to find the memory setting in java commnad line
# param 2: minimum memory limit, value should be in MiB.
# param 3: warning to emit if the value is below specified limit
check_jvm_memory() {
  regex=$1
  limit=$2
  message=$3
  memory=0
  if [[ "$CMF_JAVA_OPTS" =~ $regex ]]; then
    memory=${BASH_REMATCH[1]}
    unit=${BASH_REMATCH[2]}
    unit=$(echo $unit | tr "[:upper:]" "[:lower:]")
    if [[ "$unit" = "g" ]]; then
      memory=$((memory*1024))
    fi
  fi

  if [[ "$memory" -lt "$limit" ]]; then
    echo $message | tee -a $SERVER_OUT
    exit 1
  fi
}

# Checks various parameters to make sure that we are starting CM with
# sane values. Currently checking only JVM memory parameters.
sanity_check() {
  # check if the java perm gen is set to 256m or above, if not generate a warning
  permgen_regex="MaxPermSize=([0-9]+)([mMgG])"
  check_jvm_memory $permgen_regex $MAX_PERMGEN "[error] JVM PermGen is set less than 256m, CM server may run out of PermGen space. Update CMF_JAVA_OPTS in $CMF_DEFAULTS/$prog to fix this."

  # check if the java max heap is set to 2G or above, if not generate a warning
  maxheap_regex="Xmx([0-9]+)([mMgG])"
  check_jvm_memory $maxheap_regex $MAX_HEAP "[error] JVM MaxHeap is set less than 2G, CM server may run out of Heap space. Update CMF_JAVA_OPTS in $CMF_DEFAULTS/$prog to fix this."
}

start() {
  # check to see if the server is already running
  local_checkpid
  if [ $? = 0 ]; then
    echo "$prog is already running"
    exit 0
  fi

  install -d -o $USER -g $GROUP ${CMF_VAR:-/var}/run/cloudera-scm-server

  cat < /dev/null > $SERVER_OUT
  sanity_check
  echo -n "Starting $prog: "

  if [ -e $forcefile ]; then
    CMF_SERVER_ARGS="$CMF_SERVER_ARGS -hard-stop-commands"
    rm -f $forcefile
  fi

  $CMF_SUDO_CMD /bin/bash -c "nohup $SERVER_SCRIPT $CMF_SERVER_ARGS" >> $SERVER_OUT 2>&1 </dev/null &
  # pid is technically su's but it will die when the server dies.
  server_pid=$!
  echo $server_pid > $pidfile
  # sleep so the process can make its way to the process table - and out again
  # if it fails at startup - which could take a while.
  sleep $start_timeout
  disown -ar
  # print status information.
  local_check_start
  RETVAL=$?
  echo
  return $RETVAL
}

force_start() {
  CMF_SERVER_ARGS="$CMF_SERVER_ARGS -hard-stop-commands"
  start
}

# Stop the given process and remove the pidfile if the process has been stopped
# Return 0 if operation succeeds, 1 otherwise.
stop() {
  local_checkpid
  if [ $? != 0 ]; then
    echo "$prog is already stopped"
    return 0
  fi

  echo -n $"Stopping $prog: "
  local_killproc
  local kill_retval=$?
  local_print_stop
  if [ $kill_retval = 0 ]; then
    # Since the process has been terminated, safely remove its pid file.
    rm -f ${pidfile}
    return 0
  else
    return 1
  fi
}

status_fn() {
  if [ $is_suse -eq 1 ]; then
    echo -n "Checking for service $prog"
    local_checkpid
    rc_status -v
  else
    status -p $pidfile $prog
  fi
  RETVAL=$?
}

condrestart() {
  [ -e ${pidfile} ] && restart || :
}

restart() {
  stop
  if [ $? != 0 ]; then
    return 1
  fi
  start
}

force_start_warning() {
  echo "The 'force_start' command is not supported on systemd based distros." \
       "Please separately invoke the 'force_next_start' and 'start' commands instead."
  # Return a failure code so this doesn't become a silent no-op in an
  # automation script.
  RETVAL=-1
}

force_next_start() {
  touch $forcefile
  RETVAL=$?
}

try_restart() {
  local_checkpid
  if [ $? !=0 ];then
    echo "$prog is not running"
    return 1
  fi
  restart
}

case "$1" in
  start)
    start
    ;;
  force_start)
    if [ $is_systemd -eq 1 ]; then
      force_start_warning
    else
      force_start
    fi
    ;;
  force_next_start)
    force_next_start
    ;;
  stop)
    stop
    ;;
  status)
    status_fn
    ;;
  restart)
    restart
    ;;
  condrestart)
    condrestart
    ;;
  *)
    if [ $is_systemd -eq 1 ]; then
      echo $"Usage: $prog {start|force_next_start|stop|restart|status|condrestart}"
    else
      echo $"Usage: $prog {start|force_start|stop|restart|status|condrestart}"
    fi
    RETVAL=3
esac

exit $RETVAL