#!/bin/bash
#
# 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.

# This is a poor man's templating engine for generating init.d scripts to
# support all the Apache services that Bigtop distro has. An actual init.d
# script gets generate via running this script under bash and giving it
# a mandatory argument of a file containing the configuration for the service. 
# The argument file should be a valid piece of bash code since it gets directly
# source into this template. E.g.
#    $ bash ./init.d.tmpl hadoop-hdfs-namenode.svc rpm hadoop-hdfs-namenode
# 
# You must declare the following in your .svc configuration file:
#     DAEMON="name of the resulting init.d script"
#     DESC="Free form human readable description of the service"
#     EXEC_PATH="path to the upstream daemon management script"
#     SVC_USER="user to run this service as"
#     DAEMON_FLAGS="flags to be passed to the $EXEC_PATH"
#     WORKING_DIR="working directory to cd into before starting the daemon"
#     CONF_DIR="path to the configuration directory"
#     PIDFILE="file holding a PID of the running daemon"
#     LOCKFILE="file signifying the service lock"
#
#     CHKCONFIG="chkconfig(8) registration signature"
#     INIT_DEFAULT_START="run levels to use"
#     INIT_DEFAULT_STOP="run levels not to use ;-)"
# 
# You can, also, override parts of the generated init.d script by providing
# function definitions for: generate_start, generate_stop, generate_functions, and generate_extra_commands.
# See the default implemenations below and feel free to customize. Also look
# for exising .svc files in common to see how different services are tweaking
# the defaults.
#
# Of course, if this whole templating thing grows too big we might need to
# consider a real templating engine (I have played with m4, but it seems
# qutie brittle when used for manipulating pieces of the shell code -- think
# $0 the like).

if [ $# -lt 3 ] ; then
  echo "Usage: ${BASH_SOURCE-0} service.definition.svc rpm|deb init.d.script"
  exit 1
fi

# Override anything necessary for supported systems
case "$2" in
  "deb" )
    # The defaults will work well on Debian-based systems
    ;;
  "rpm" )
    # On RedHat, SuSE and Mageia run-level 2 is networkless, hence excluding it
    CHKCONFIG="345 85 15"
    INIT_DEFAULT_START="3 4 5"
    INIT_DEFAULT_STOP="0 1 2 6"
    ;;
  "*" )
    ;;
esac

# Create the init script, make it executable, and send stdout to it
mkdir -p `dirname $3`
touch $3
chmod 0755 $3
exec > $3

generate_start() {

cat <<'__EOT__'

start() {
  [ -x $EXEC_PATH ] || exit $ERROR_PROGRAM_NOT_INSTALLED
  [ -d $CONF_DIR ] || exit $ERROR_PROGRAM_NOT_CONFIGURED

  su -s /bin/bash $SVC_USER -c "cd $WORKING_DIR && $EXEC_PATH --config '$CONF_DIR' start $DAEMON_FLAGS"

  # Some processes are slow to start
  sleep $SLEEP_TIME
  checkstatusofproc
  RETVAL=$?

  if [ $RETVAL -eq $STATUS_RUNNING ]; then
    touch $LOCKFILE
    log_success_msg "Started ${DESC}: "
  else
	log_failure_msg "Failed to start ${DESC}. Return value: $RETVAL"
  fi
  return $RETVAL
}

__EOT__

}

generate_stop() {

cat <<'__EOT__'

stop() {
  start_daemon $EXEC_PATH --config "$CONF_DIR" stop $DAEMON_FLAGS
  RETVAL=$?

  if [ $RETVAL -eq $RETVAL_SUCCESS ]; then
	 log_success_msg "Stopped ${DESC}: "
	 rm -f $LOCKFILE $PIDFILE
 else
	 log_failure_msg "Failed to stop ${DESC}. Return value: $RETVAL."
 fi
}

__EOT__

}

generate_functions() {
    :
}

generate_extra_commands() {

cat <<'__EOT__'
    *)
      echo $"Usage: $0 {start|stop|status|restart|try-restart|condrestart}"
      exit 1
__EOT__

}

###################################################################
# Some reasonable defaults for the run-level settings, these are
# tweaked on a per-OS basis from the SPEC/rules files that call us
# and can be further tweaked inside of individual .svc templates
CHKCONFIG=${CHKCONFIG:-"2345 85 15"}
INIT_DEFAULT_START=${INIT_DEFAULT_START:-"2 3 4 5"}
INIT_DEFAULT_STOP=${INIT_DEFAULT_STOP:-"0 1 6"}

###################################################################
# NOTE how we are sourcing the argument here so that a user-defined
# settings have a chance to override the default values for 
# generate_start, generate_stop, generate_functions and generate_extra_commands. If you
# ever want to make this template even more flexible -- define the
# default values above this line
. $1

cat <<__EOT__
#!/bin/bash
#
# 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.
#
# Starts a $DESC
#
# chkconfig: $CHKCONFIG
# description: $DESC
#
### BEGIN INIT INFO
# Provides:          $DAEMON
# Short-Description: $DESC
# Default-Start:     $INIT_DEFAULT_START
# Default-Stop:      $INIT_DEFAULT_STOP
# Required-Start:    \$syslog \$remote_fs
# Required-Stop:     \$syslog \$remote_fs
# Should-Start:
# Should-Stop:
### END INIT INFO

. /lib/lsb/init-functions
BIGTOP_DEFAULTS_DIR=\${BIGTOP_DEFAULTS_DIR-/etc/default}
[ -n "\${BIGTOP_DEFAULTS_DIR}" -a -r \${BIGTOP_DEFAULTS_DIR}/hadoop ] && . \${BIGTOP_DEFAULTS_DIR}/hadoop
[ -n "\${BIGTOP_DEFAULTS_DIR}" -a -r \${BIGTOP_DEFAULTS_DIR}/$DAEMON ] && . \${BIGTOP_DEFAULTS_DIR}/$DAEMON

# Autodetect JAVA_HOME if not defined
. /usr/lib/bigtop-utils/bigtop-detect-javahome

RETVAL_SUCCESS=0

STATUS_RUNNING=0
STATUS_DEAD=1
STATUS_DEAD_AND_LOCK=2
STATUS_NOT_RUNNING=3
STATUS_OTHER_ERROR=102


ERROR_PROGRAM_NOT_INSTALLED=5
ERROR_PROGRAM_NOT_CONFIGURED=6


RETVAL=0
SLEEP_TIME=5
PROC_NAME="java"

DAEMON="$DAEMON"
DESC="$DESC"
EXEC_PATH="$EXEC_PATH"
SVC_USER="$SVC_USER"
DAEMON_FLAGS="$DAEMON_FLAGS"
CONF_DIR="$CONF_DIR"
PIDFILE="$PIDFILE"
LOCKDIR="/var/lock/subsys"
LOCKFILE="\$LOCKDIR/$DAEMON"
WORKING_DIR="${WORKING_DIR:-~/}"

install -d -m 0755 -o $SVC_USER -g $SVC_USER $(dirname $PIDFILE) 1>/dev/null 2>&1 || :
[ -d "\$LOCKDIR" ] || install -d -m 0755 \$LOCKDIR 1>/dev/null 2>&1 || :
__EOT__

generate_functions
generate_start
generate_stop

cat <<'__EOT__'
restart() {
  stop
  start
}

checkstatusofproc(){
  pidofproc -p $PIDFILE $PROC_NAME > /dev/null
}

checkstatus(){
  checkstatusofproc
  status=$?

  case "$status" in
    $STATUS_RUNNING)
      log_success_msg "${DESC} is running"
      ;;
    $STATUS_DEAD)
      log_failure_msg "${DESC} is dead and pid file exists"
      ;;
    $STATUS_DEAD_AND_LOCK)
      log_failure_msg "${DESC} is dead and lock file exists"
      ;;
    $STATUS_NOT_RUNNING)
      log_failure_msg "${DESC} is not running"
      ;;
    *)
      log_failure_msg "${DESC} status is unknown"
      ;;
  esac
  return $status
}

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

check_for_root() {
  if [ $(id -ur) -ne 0 ]; then
    echo 'Error: root user required'
    echo
    exit 1
  fi
}

service() {
  case "$1" in
    start)
      check_for_root
      start
      ;;
    stop)
      check_for_root
      stop
      ;;
    status)
      checkstatus
      RETVAL=$?
      ;;
    restart)
      check_for_root
      restart
      ;;
    condrestart|try-restart)
      check_for_root
      condrestart
      ;;
__EOT__

generate_extra_commands

cat <<'__EOT__'
  esac
}

service "$1"

exit $RETVAL
__EOT__