#!/bin/bash
#
# (c) Copyright 2011-2012 Cloudera, Inc.
#
# Init script for the Cloudera SCM Server's Embedded Database (postgresql).
#
# chkconfig: 2345 79 11
# description: Cloudera SCM Server Embedded DB.

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

DATA_DIR=/var/lib/cloudera-scm-server-db/data

# Source function library.
# This not only pulls in functions that we don't use,
# but it also sanitizes the environment a bit
# by setting standard umask, PATH, etc.
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

# For SELinux we need to use 'runuser' not 'su'
USER=cloudera-scm
if [ -x /sbin/runuser ]; then
    SU="runuser -s /bin/bash $USER"
else
    SU="su -s /bin/bash $USER"
fi

fast_stop_file=/var/run/cloudera-scm-server/db_fast_next_stop

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

RETVAL=0
SERVER_LOGFILE="/var/log/cloudera-scm-server/db.log"

# On some distros, with some versions of postgresql, the
# initdb and pg_ctl binaries are not in the default path.
# However, in these cases, 'psql' is a symlink to a binary
# in some directory where we can also find initdb and pg_ctl,
# so we can find psql's home and add it to the path. If that
# location is already in the path, this is harmless, so it's
# not worth making conditional.
PG_PATH=$(dirname $(readlink -f $(which psql)))
PATH="$PG_PATH:$PATH"

# On systemd based distros, postgresql is configured to place
# its socket files in /var/run/postgresql which can only be written
# to by the 'postgres' user. But, of course, we do not run the
# embedded DB as 'postgres'. So we need to assign a different
# location for the socket files. Rather than alter behaviour on
# all systems, we only override this if /var/run/postgresql exists.
if [ -d '/var/run/postgresql' ]; then
  # initialize_embedded_db.sh will automatically consume $EXTRA_PG_ARGS
  export EXTRA_PG_ARGS='-k /var/run/cloudera-scm-server/'
fi

start()
{
  # Ensure the run directory exists in case we need it for the socket files.
  install -d -o $USER -g $USER /var/run/cloudera-scm-server

  # Run the initdb script to make sure the DB is correctly provisioned.
  INITIALIZE_SCRIPT="/usr/share/cmf/bin/initialize_embedded_db.sh"
  $SU -c "$INITIALIZE_SCRIPT $DATA_DIR $SERVER_LOGFILE" || return $?

  # Start the database.
  STATUS=$($SU -c "pg_ctl status -D $DATA_DIR")
  if [[ $? -ne 0 ]]; then
      $SU -c "pg_ctl start -w -D $DATA_DIR -l $SERVER_LOGFILE -o \"$EXTRA_PG_ARGS\""
  else
      # Already started
      echo $STATUS
  fi
  return $?
}


do_stop()
{
  SHUTDOWN_MODE=$1
  STATUS=$($SU -c "pg_ctl status -D $DATA_DIR")
  if [[ $? -eq 0 ]]; then
      $SU -c "pg_ctl stop -m $SHUTDOWN_MODE -w -D $DATA_DIR"
  else
      # Already stopped
      echo $STATUS
  fi
  RETVAL=$?
}

stop()
{
  local MODE=smart
  if [ -e $fast_stop_file ]; then
    MODE=fast
    rm -f $fast_stop_file
  fi
  do_stop $MODE
}

fast_stop()
{
  do_stop fast
}

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

next_stop_fast() {
  touch $fast_stop_file
  RETVAL=$?
}

case "$1" in
  initdb)
    # This is here for backwards compatibility, in case any user scripts
    # reference this command. But it's not listed in the usage anymore, and is
    # just a no-op.
    ;;
  start)
    start
    RETVAL=$?
    ;;
  stop)
    stop
    RETVAL=$?
    ;;
  fast_stop)
    if [ $is_systemd -eq 1 ]; then
      fast_stop_warning
    else
      fast_stop
    fi
    RETVAL=$?
    ;;
  next_stop_fast)
    next_stop_fast
    ;;
  status)
    $SU -c "pg_ctl status -D $DATA_DIR"
    RETVAL=$?
    ;;
  restart)
    stop && start
    RETVAL=$?
    ;;
  *)
    if [ $is_systemd -eq 1 ]; then
      echo "Usage: $prog {start|stop|next_stop_fast|restart|status}"
    else
      echo "Usage: $prog {start|stop|fast_stop|restart|status}"
    fi
    RETVAL=3
esac

exit $RETVAL