#!/bin/bash 
# Simple backupscript for PGSQL databases
# Author: Lars Vogdt
# BSD3 Clause License
#

PATH=/bin:/usr/bin

#
# Binaries
#
AWK='/usr/bin/awk'
GREP='/usr/bin/grep'
HOSTNAME_BIN='/usr/bin/hostname'
MAILX='/usr/bin/mail'
SEND_NSCA_BIN='/usr/bin/send_nsca'
PG_DUMP='/usr/bin/pg_dump'
PG_ISREADY='/usr/bin/pg_isready'
PGREP='/usr/bin/pgrep'
PGSQL='/usr/bin/psql'
SED='/usr/bin/sed'
TAIL='/usr/bin/tail'
#
# Options
#
DISTCONFIG='/etc/sysconfig/postgresql-backupscript'
NAGIOSHOST='localhost'
NAGIOS_SERVICE_NAME='PostgreSQL backup'
PGSQL_OPTS=''
SEND_NSCA_CONFIG='/etc/send_nsca.cfg'
SEND_NSCA_HOSTNAME=$(hostname -s)
USE_NSCA='no'
USE_EMAIL='yes'
##################################################
# Default/Fallback values
# Don't change them here! Use $DISCONFIG instead
##################################################
ABORT_ON_ERROR='no'
BACKUPDIR='/root/backup/postgres'
CONFIG_FILES="pg_hba.conf pg_ident.conf postgresql.auto.conf postgresql.conf"
FQHOSTNAME=$($HOSTNAME_BIN -f)
HOST=$($HOSTNAME_BIN -s 2>/dev/null)
LOGNAME='pgsql-backup'
LOGFILE="/var/log/${LOGNAME}.log"
EMAIL='root@localhost'
START_BACKUP='yes'
EXCLUDE_DB=''
FORCE_BACKUP='no'
DEBUG='no'
RETENTION=14
COMPRESS_EXE='/usr/bin/xz'
COMPRESS_OPTS=''
COMPRESS_AFTER_UNLOCK='yes'
PGSQL_SCRIPT_BEFORE_DUMP=''
PGSQL_SCRIPT_AFTER_DUMP=''
PGSQL_SCRIPT_AFTER_COMPRESSION=''
##################################################
umask 027
unset LANG;

cleanup_and_exit(){
    test -n "$TMPFILE" -a -f "$TMPFILE" && rm "$TMPFILE"
    exit $1
}

LOG(){
    local MESSAGE="$1"
    local LOG_DATE=$(date "+%b %d %H:%M:%S")
    if [ -z "$LOGFILE" ]; then
        HANDLE_MESSAGE "ERROR: LOGFILE is not defined" 1
        cleanup_and_exit 1
    fi
    if [ ! -d "$LOGDIR" ]; then
        mkdir -p "$LOGDIR" || exit 1
        echo "$LOG_DATE $HOST $LOGNAME[$$]: function LOG created $LOGDIR" > "$LOGFILE"
    fi
    echo "$LOG_DATE $HOST $LOGNAME[$$]: $MESSAGE" >> $LOGFILE || DEBUG="yes"
    if [ "$DEBUG" = "yes" ]; then
        echo "DEBUG:    $MESSAGE"
    fi    
}

SEND_NSCA(){
    local MESSAGE="$1"
    local EXIT_CODE="$2"
    echo -e "$SEND_NSCA_HOSTNAME\t$NAGIOS_SERVICE_NAME\t$EXIT_CODE\t$MESSAGE" | $SEND_NSCA_BIN -H $NAGIOSHOST -c $SEND_NSCA_CONFIG 1>/dev/null
}

SEND_EMAIL(){
    local MESSAGE="$1"
    local EXIT_CODE="$2"
    case $EXIT_CODE in 
        0) MESSAGE="OK: $MESSAGE" ;;
        1) MESSAGE="ERROR: $MESSAGE" ;;
        2) MESSAGE="WARNING: $MESSAGE" ;;
        3) MESSAGE="UNKNOWN: $MESSAGE" ;;
    esac
    echo "$MESSAGE" | $MAILX -s "[$LOGNAME] on $FQHOSTNAME" $EMAIL
}

HANDLE_MESSAGE(){
    local MESSAGE="$1"
    local EXIT_CODE="$2"
    case "$USE_NSCA" in
        [Yy][Ee][Ss]) SEND_NSCA "$MESSAGE" "$EXIT_CODE" ;;
    esac
    case "$USE_EMAIL" in
        [Yy][Ee][Ss]) SEND_EMAIL "$MESSAGE" "$EXIT_CODE" ;;
    esac
}

test_postmaster_alive(){
    local tmpfile="$1"
    $PG_ISREADY $PGSQL_OPTS 1>/dev/null 2>>"$tmpfile"
    if [ $? -ne 0 ]; then 
      if [ -s "$tmpfile" ]; then
          HANDLE_MESSAGE "$(cat $tmpfile)" 1
          LOG "$(cat "$tmpfile")"
          cleanup_and_exit 1
      fi
    fi
}

print_help(){
    echo "Usage: $(basename $0) [-c <configfile>]"
    echo 
    echo "       -d              : print debug output"
    echo "       -f              : force backup (incl. remove backups in same directory)"
    echo "       -h              : print this message"
    echo "       -c <configfile> : use the given config file instead of $DISTCONFIG"
    echo
    echo " The target of this script is to create backups of your PGSQL databases"
    echo " on a regular daily bases."
    echo " Please find the configuration details in $DISTCONFIG - if you want to"
    echo " test something, the option -f might be useful to use another file containing"
    echo " the configuration."
    echo
    echo " PLEASE NOTE: "
    echo "  Please have a look at /usr/share/doc/packages/postgresql-backupscript/README.SUSE"
    echo "  as this contains information for password protected databases and further"
    echo "  details."
    exit 0
}

get_datadir(){
  DATADIR=$($PGREP -u postgres -fa -- -D | $TAIL -n1 | $AWK '" " { print $4 }')
  if [ -d "$DATADIR" ]; then
    echo "$DATADIR"
  else
    LOG "ERROR: Could not find DATADIR (got $DATADIR)"
    HANDLE_MESSAGE "Could not find DATADIR (got $DATADIR)" 1
    cleanup_and_exit 1
  fi
}

create_dir(){
    local directory="$1"
    mkdir -p "$directory" 2>"$TMPFILE" || { 
        HANDLE_MESSAGE "$(cat $TMPFILE)" 1
        LOG "$(cat "$TMPFILE")"
        cleanup_and_exit 1
    }
}

function compress_dump() {
  db_sql="$1"
  local FUNC_EXIT=0
  if [ -x "$COMPRESS_EXE" ]; then
    LOG "Compressing $db_sql using '$COMPRESS_EXE $COMPRESS_OPTS $db_sql'"
    if ! $COMPRESS_EXE $COMPRESS_OPTS "$db_sql"
    then
      LOG "Compression of $db failed"
      if [ "$ABORT_ON_ERROR" = 'yes' ]; then
        cleanup_and_exit 1
      fi
      FUNC_EXIT=1
    fi
  else
    LOG "Not compressing $db.sql as $COMPRESS_EXE is not executable"
  fi
  return "$FUNC_EXIT"
}

trap cleanup_and_exit 0 1 2 3 7 13 15

while getopts 'dhfc:'  OPTION ; do
    case $OPTION in
        d) DEBUG='yes'
        ;;
        f) START_BACKUP='yes'
           FORCE_BACKUP='yes'
        ;;
        h) print_help
        ;;
        c) DISTCONFIG="$OPTARG"
        ;;
    esac
done
shift $(( OPTIND - 1 ))

for binary in "$AWK" "$COMPRESS_EXE" "$GREP" "$HOSTNAME_BIN" "$PG_DUMP" "$PG_ISREADY" "$PGREP" "$PGSQL" "$SED" "$TAIL" ; do
    if [ ! -x "$binary" ]; then
        LOG "ERROR: bnary $binary can not be executed"
        HANDLE_MESSAGE "Binary: $binary can not be executed" 1
        cleanup_and_exit 1
    fi
done
case $USE_NSCA in 
    [Yy][Ee][Ss]) 
        if [ ! -x "$SEND_NSCA_BIN" ]; then 
            LOG "ERROR: $SEND_NSCA_BIN can not be executed"
            cleanup_and_exit 1
        fi
        if [ ! -r "$SEND_NSCA_CONFIG" ]; then
            LOG "ERROR: can not read $SEND_NSCA_CONFIG" 
            cleanup_and_exit 1
        fi
    ;;
esac
case "$USE_EMAIL" in
    [Yy][Ee][Ss]) 
        if [ ! -x "$MAILX" ]; then
            LOG "ERROR: $MAILX can not be executed"
        fi
    ;;
esac

# source our config
if [ -f "$DISTCONFIG" ]; then
    . "$DISTCONFIG"
    LOGDIR=$(dirname "$LOGFILE")
else
    echo "$DISTCONFIG not found - using defaults" >&2
    LOGDIR=$(dirname "$LOGFILE")
    LOG "$DISTCONFIG not found - using defaults"
fi

case "$START_BACKUP" in
  [Yy]*)
    FINAL_EXIT=0
    DATE=$(date "+%Y%m%d")
    BEGIN_SECONDS=$(date +%s)
    TMPFILE=$(mktemp /tmp/postgresql-backupscript-XXXXXX)
    if ! test -d "$BACKUPDIR" -a "$FORCE_BACKUP" != 'yes' ; then
        case "$CREATE_BACKUPDIR" in 
            [Nn][Oo])
                HANDLE_MESSAGE "$BACKUPDIR does not exist. Exiting as CREATE_BACKUPDIR is set to 'no' in $DISTCONFIG" 1
                LOG "ERROR: $BACKUPDIR does not exist. Exiting as CREATE_BACKUPDIR is set to 'no' in $DISTCONFIG"
                cleanup_and_exit 1
            ;;
            [Ss][Kk][Ii][Pp])
                cleanup_and_exit 0
            ;;
            *)
                create_dir "$BACKUPDIR"
            ;;
        esac
    fi
    if [ -d "$BACKUPDIR/$DATE" ]; then
        if [ "$FORCE_BACKUP" == 'yes' ]; then
            LOG "$BACKUPDIR/$DATE already exists - cleaning up, as option --force is used"
            rm -rf "$BACKUPDIR/$DATE"
            create_dir "$BACKUPDIR/$DATE"
        else
            HANDLE_MESSAGE "$BACKUPDIR/$DATE exists"
            LOG "$BACKUPDIR/$DATE already exists - aborting backup"
            cleanup_and_exit 1
        fi
    else
        create_dir "$BACKUPDIR/$DATE"
    fi
    pushd "$BACKUPDIR/$DATE" 1>/dev/null
    PG_DATADIR=$(get_datadir)
    for config in $CONFIG_FILES; do
      if [ -r "$PG_DATADIR/$config" ]; then
        LOG "Creating backup of $PG_DATADIR/$config"
        cp -L "$PG_DATADIR/$config" "$BACKUPDIR/$DATE/" 
      fi
    done
    test_postmaster_alive "$TMPFILE"
    if [ -n "$PGSQL_SCRIPT_BEFORE_DUMP" ]; then
        LOG "Executing $PGSQL_SCRIPT_BEFORE_DUMP"
        "$PGSQL_SCRIPT_BEFORE_DUMP"
    fi
    ALL_DATABASES=$(su - postgres -c "$PGSQL $PGSQL_OPTS -A -P format=unaligned -t -c 'SELECT datname from pg_database;'")
    # If DBs are excluded
    for exclude in $EXCLUDE_DB; do
        ALL_DATABASES=$(echo $ALL_DATABASES | $SED "s/\b$exclude\b//g")
    done
    # start the real backup
    for db in $ALL_DATABASES; do
        if [ -s "$TMPFILE" ]; then
            HANDLE_MESSAGE "PGSQL: $(cat $TMPFILE)" 1
            LOG "$(cat "$TMPFILE")"
            cleanup_and_exit 1
        fi
        LOG "Creating backup of $db"
        if ! su - postgres -c "$PG_DUMP $PGSQL_OPTS --clean --if-exists --create --format=plain --quote-all-identifiers --dbname=$db" >> "$db.sql"
        then
            LOG "Dump of $db failed"
            if [ "$ABORT_ON_ERROR" = 'yes' ]; then
                cleanup_and_exit 1
            fi
            FINAL_EXIT=1
        fi
        if [ "$COMPRESS_AFTER_UNLOCK" != "yes" ]; then
            if ! compress_dump "$db.sql"
            then
                FINAL_EXIT=1
            fi
        fi
        chmod 640 $db.sql*
    done
    if [ -n "$PGSQL_SCRIPT_AFTER_DUMP" ]; then
        LOG "Executing $PGSQL_SCRIPT_AFTER_DUMP"
        "$PGSQL_SCRIPT_AFTER_DUMP"
    fi
    for db in $ALL_DATABASES ; do
        if [ "$COMPRESS_AFTER_UNLOCK" = "yes" ]; then
            if ! compress_dump "$db.sql"
            then
                FINAL_EXIT=1
            fi
        fi
        chmod 640 $db.sql*
    done
    if [ -s "$TMPFILE" ]; then
        HANDLE_MESSAGE "PGSQL: $(cat $TMPFILE)" 1
        LOG "$(cat "$TMPFILE")"
        cleanup_and_exit 1
    fi
    popd 1>/dev/null
    chmod 750 "$BACKUPDIR/$DATE"
    if [ -n "$PGSQL_SCRIPT_AFTER_COMPRESSION" ]; then
        LOG "Executing $PGSQL_SCRIPT_AFTER_COMPRESSION"
	"$PGSQL_SCRIPT_AFTER_COMPRESSION"
    fi
    if [ -n "$RETENTION" -a "$RETENTION" -gt 0 ]; then
        LOG "removing backups older than $RETENTION days"
        find "$BACKUPDIR" -ctime +$RETENTION -print0 | xargs -0 rm -rf {} | grep -v "No such file or directory" 
    fi
    END_SECONDS=$(date +%s)
    RUNTIME_RAW_SECONDS=$[$END_SECONDS-$BEGIN_SECONDS]
    RUNTIME_HOURS=$[$RUNTIME_RAW_SECONDS/3600]
    RUNTIME_MINUTES=$[$[$RUNTIME_RAW_SECONDS%3600]/60]
    RUNTIME_SECONDS=$[$[$RUNTIME_RAW_SECONDS%3600]%60]
    LOG "backup finished. Duration (hh:mm:ss): $RUNTIME_HOURS:$RUNTIME_MINUTES:$RUNTIME_SECONDS"
    case $USE_NSCA in
       [Yy][Ee][Ss])
           SEND_NSCA "Finished: $(date); Duration (hh:mm:ss): $RUNTIME_HOURS:$RUNTIME_MINUTES:$RUNTIME_SECONDS | time=$RUNTIME_RAW_SECONDS;" 0
       ;;
    esac
    cleanup_and_exit "$FINAL_EXIT"
  ;;
  *)
    cleanup_and_exit 0
  ;;
esac
cleanup_and_exit 0
