__ExportDB

#!/bin/bash

function __msg_error() {
    printf 'ERROR from line: %s %s\n' "${BASH_LINENO[$(( ${#BASH_LINENO[@]} - 2 ))]}" "$*"
}

# Do not run if an instance is already running
# -------------------------------------------------------------------------------------
RFLAG="/tmp/___RUNNING_FLAG___$( basename "${BASH_SOURCE[0]}" )"
mkdir "$RFLAG" 2>/dev/null || { __msg_error "There is an already running instance of this program"; exit 1; }

# some functions
# -------------------------------------------------------------------------------------
on_exit() {
        __msg_error "Abnormal Exit"
        rmdir "$RFLAG" 2>/dev/null
}
trap on_exit EXIT # Enable emergency handler

clean_exit () {
    rmdir "$RFLAG" 2>/dev/null
    trap - EXIT # Disable emergency handler
    exit 0
}

LOG_FILE="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd -P )/LOG__$( basename "${BASH_SOURCE[0]}" )"

get_date () {
    local day_str

    day_str=$(date +'%A')
    day_str=$(printf "%s%0$((10 - ${#day_str}))d" "$day_str" 0)
    echo -n "${day_str//0/_}$(date "+%d-%m-%Y__%H.%M.%S")"
}
date=$(get_date)

HOST="my_dbserver"
DB="my_database"
USER="my_database_admin"
PASSWD="a_simple_passwd"


# exec and redirect stdout to log file
# -------------------------------------------------------------------------------------
touch "$LOG_FILE"
exec >>"$LOG_FILE" 2>&1

printf '\n\nExporting '%s' database on %s ... ' "$DB" "$date"

BACKUP_DIR=/srv/mysql_exports
export TZ=Europe/Athens
umask 077
keep=5

mkdir -p "$BACKUP_DIR"       || { __msg_error "Could not create directory $BACKUP_DIR. Exiting"; exit 1; }
cd "$BACKUP_DIR" 2>/dev/null || { __msg_error "Could not change directory to $BACKUP_DIR. Exiting"; exit 1; }

ignored_tables=(
        '--ignore-table=my_database.table1'
        '--ignore-table=my_database.table2'
        '--ignore-table=my_database.table3'
        '--ignore-table=my_database.table4'
        '--ignore-table=my_database.table5'
        '--ignore-table=my_database.table6'
        '--ignore-table=my_database.log'
        '--ignore-table=my_database.log_archive'
)

/usr/bin/mysqldump  \
        --host="$HOST" \
        --user="$USER" --password="$PASSWD" \
        --opt --allow-keywords \
        --add-drop-database \
        --single-transaction \
        "${ignored_tables[@]}" \
        "$DB" > "${HOST}__${DB}__export__${date}.sql"


# echo -n "Compressing Exported Data ... "
# gzip --quiet "${HOST}__${DB}__export__${date}.sql"

delete_old_exports() {
    # Delete all dumps older than $keep days, or the 1st of any month
    # -------------------------------------------------------------------------------------
    # accepts two parameters:
    #  keep: how many exports to keep (assuming every day an export is performed)
    #  ext:  the extension of the files to inspect

    (( $# != 2 )) && { __msg_error "inadequate parameters passed to function ${FUNCNAME[0]}"; exit 1; }
    [[ ${1+isset} = isset ]]  || { __msg_error "keep parameter not passed to function ${FUNCNAME[0]}"; exit 1; }
    [[ ${2+isset} = isset ]]  || { __msg_error ".ext parameter not passed to function ${FUNCNAME[0]}"; exit 1; }
    [ ! -z "${1##*[!0-9]*}" ] || { __msg_error "keep parameter passed to ${FUNCNAME[0]}() is not a possitive integer"; exit 1; }

    keep=$(( "$1" - 1 )); ext="$2"

    printf '\nDeleting old exports matching *.%s...\n' "$ext"
    find . -name '*.'"$ext" -type f -mtime +${keep} -print0 | \
        while read -r -d '' old_export; do
            # day is %d
            day=$(date +%d --date "@$(stat --format '%Z' "$old_export")")
            if [[ $day != "01" ]]; then
                echo "  deleting" "$old_export"
                rm -f "$old_export"
            fi
        done
    echo 'Deletions completed'
}

delete_old_exports "$keep" "sql"

printf '\nDone\n---\n'


# delete the semaphore directory and exit
# -------------------------------------------------------------------------------------
clean_exit