#!/bin/bash

export LANG=C
export LC_ALL=C

rdbver=1.1

keyname=$2

test -d $3 || mkdir -p $3
log_file=$3/${0##*/}.log

## redis opts
redis_cli_opts='--raw'
redis_bgsave_timeout=300
redis_bgsave_one_try_timeout=15

redis_data_dir='/var/lib/redis'
redis_rdp_location="$redis_data_dir/dump.rdb"

test -f $redis_rdp_location || { 
    redis_data_dir='/var/spool/redis'
    redis_rdp_location="$redis_data_dir/dump.rdb"
}

redis_backup_dir=$redis_data_dir

current_date=`date '+%Y%m%d-%H%M%S'`

## choosing compress
bzip=`which bzip2 2>/dev/null`; pbzip=`which pbzip2 2>/dev/null`; gzip=`which gzip 2>/dev/null`; bzcompress=${pbzip:-${bzip}}; compress_prog=${bzcompress:-${gzip}}
test -x "$compress_prog" || { echo "[ERROR `date '+%Y/%m/%d-%H:%M:%S'`] No compress util or $compress_prog has no execute flag. Fix it first."; exit 1; }

case "${compress_prog##*/}" in
        'pbzip2' ) compress_ext='bz2'; tar --version | grep -oE '1.2[0-6]' > /dev/null || compress_prog+=' -l' ;;
        'bzip2'  ) compress_ext='bz2' ;;
        'gzip'   ) compress_ext='gz' ;;
esac

function show_error() {
        local message="$1"; local funcname="$2"; local log_date=`date '+%Y/%m/%d:%H:%M:%S'`
        echo -e "[ERROR.$funcname $log_date] $message" >> $log_file 2>&1
}

function show_notice() {
        local message="$1"; local funcname="$2"; local log_date=`date '+%Y/%m/%d:%H:%M:%S'`
        echo -e "[NOTICE.$funcname $log_date] $message" >> $log_file 2>&1
}

function show_usage() {
    echo "Usage: ${0##*/} --(get|remove) <domain name> <log path>" 
    echo -e "\t Example: ${0##*/} --get example.ru /var/log"
    echo -e "\t Example: ${0##*/} --remove example.ru /var/log" 
}

function backup_redis() {
    local err=0; local dir=$1; local seconds=0;
    which redis-cli > /dev/null || { show_error "Not found redis-cli." "$FUNCNAME"; return 1;}
    test $# -eq 1 || { show_error "Function wrong usage! Args=$@" "$FUNCNAME"; return 1; }
    test -d $dir || mkdir -p $dir
    local lastsave_before=`echo lastsave | redis-cli $redis_cli_opts`
    echo bgsave | redis-cli $redis_cli_opts
    while [  $seconds -lt $redis_bgsave_timeout ]; do
        sleep $redis_bgsave_one_try_timeout
        let seconds=seconds+$redis_bgsave_one_try_timeout
        local lastsave_after=`echo lastsave | redis-cli $redis_cli_opts`
        show_notice "Curent seconds: $seconds. Lastsave before: $lastsave_before, lastsave after: $lastsave_after." "$FUNCNAME"
        test "x$lastsave_before" != "x$lastsave_after" && {
            show_notice "Saving $redis_rdp_location to $dir/${current_date}-redis.rdb, and compress" "$FUNCNAME"
            cp $redis_rdp_location $dir/${current_date}-redis.rdb && \
            nice -n 19 ionice -c 3 $compress_prog -f $dir/${current_date}-redis.rdb || \
            { show_error "Error on copy and compress $redis_rdp_location" "$FUNCNAME"; local err=1; }
            return $err;
        }
    done
    show_error "Attempt to backup redis rdb has ended by timeout: $redis_bgsave_timeout seconds!" "$FUNCNAME"; return 1;
}

function remove_redis_db() {
        redis-cli $redis_cli_opts -n $dbnumber flushdb
        redis-cli $redis_cli_opts DEL $keyname
        show_notice "Database $keyname with dbnumber=$dbnumber removed." "get_redis_db_number"
}

function get_redis_db_number() {
        which redis-cli > /dev/null || { show_error "Not found redis-cli." "$FUNCNAME"; return 1;}
        dbnumber=`redis-cli $redis_cli_opts GET $keyname`
        show_notice "Curent dbnumber for key $keyname=$dbnumber" "$FUNCNAME"
}

function get_redis_db_list() {
        which redis-cli > /dev/null || { show_error "Not found redis-cli." "$FUNCNAME"; return 1;}
        dblist=`redis-cli $redis_cli_opts INFO keyspace |grep db |grep -v db0 |awk -F':' '{print $1}' | sed 's/db//' | sort | uniq |tr '\n' ' '`
        show_notice "Redis dblist: $dblist" "$FUNCNAME"
}

function get_redis_db_not_used_number() {
        local i=1;
        while true
        do
            echo $dblist | tr ' ' '\n' | grep -qE "^${i}$" || break
            i=$((i + 1));
        done

        dbnumber=$i
        show_notice "Uniq dbnumber: $dbnumber" "$FUNCNAME"
}

function create_redis_key_with_db_number() {
        redis-cli $redis_cli_opts SET $keyname "$dbnumber"
        show_notice "Created key: $keyname with value=$dbnumber" "$FUNCNAME"
}

test x"$1" = "x" -o x"$2" = "x" -o x"$3" = "x" && { echo "One or more arguments is missing!"; show_usage; exit 1; }
test x"$1" == x"" && show_usage

test x"$1" = x"--get" && {

    get_redis_db_number

    check=`echo $dbnumber | grep -E ^\-?[0-9]+$`
    test "$check" = '' && {
        show_notice "Database $keyname not exist, script generate new database number." "get_redis_db_number"
        backup_redis $redis_backup_dir && \
        get_redis_db_list && \
        get_redis_db_not_used_number && \
        create_redis_key_with_db_number
    } >> $log_file 2>&1

    echo $dbnumber
    exit 0
}

test x"$1" = x"--remove" && {

    get_redis_db_number
    check=`echo $dbnumber | grep -E ^\-?[0-9]+$`
    test "$check" = '' && {
        show_notice "Can't remove database $keyname, not exist." "get_redis_db_number"
        exit 1;
    } >> $log_file 2>&1

    backup_redis $redis_backup_dir && \
    remove_redis_db
    exit 0
}