#!/bin/bash
# -------------------------------------------------------------------------
# Script to generate mysqldump from wordpress running inside a container
#
# Copyright (C) 2016  Aline Freitas <aline@alinefreitas.com.br>
#
# It has two command line arguments:
# -c: the docker container name
# -d: the html volume in your host pointing to the root of your wordpress installation.
# It needs to be where exist the wp-config.php file.
#
# Usage:
# wp-mysqldump.sh -c <container> -d <docker html path>
# YOu may need also to set the following variables

# Where you want to save your backups. They will be created in a subdir with the same name
# as the container.
BACKUP_DIR="/root/mysqlbackups"

# The generated extension for the backup file.
BACKUP_EXTENSION="*.mysqldump"

# The maximum amount of files to keep. If you dont want to delete any of then just comment
# out this line.
BACKUP_MAX_FILES=30

usage() {
    echo "Usage: $0 -c <container> -d <docker html path>"
    echo "Example: $0 -c www-mariadb -d /data/www.lambda3.com.br/html"
}

while getopts ":c:d:" opt; do
    case "$opt" in
        c)
            CONTAINER=$OPTARG
            ;;
        d)
            DOCKER_HTML_PATH=$OPTARG
            ;;
        *)
            echo 'Invalid argument.'
            usage
            exit 1
            ;;
    esac
done

if [ $# -eq 0 ]; then
    usage
    exit 1
fi

if [ -z ${CONTAINER} ] || [ -z ${DOCKER_HTML_PATH} ]; then
    echo "Missing parameters."
    usage
    exit 1
fi

if ! docker ps -q -f name=$CONTAINER &>/dev/null
then
    echo "Docker container not running..."
    exit 1
fi


wp_get_value() {
    local wp_config_path="$DOCKER_HTML_PATH/wp-config.php"
    if [ -r $wp_config_path ]; then
        echo $(sed -n "/^ *define( *'$1', *'\([^']*\)'.*/ {s//\1/p;q;}" $wp_config_path)
    else
        echo "Missing wp-config.php."
        return 1
    fi
}

backup_generate() {
    test -d ${BACKUP_DIR}/${CONTAINER} || mkdir ${BACKUP_DIR}/${CONTAINER}
    docker exec $CONTAINER /usr/bin/mysqldump --user=$(wp_get_value DB_USER) --password=$(wp_get_value DB_PASSWORD) $(wp_get_value DB_NAME) > ${BACKUP_DIR}/${CONTAINER}/$CONTAINER-$(date +"%Y%m%d-%H%M").sqldump
}

remove_older() {
    filenum=$(ls -1 $BACKUP_DIR/$CONTAINER | grep $BACKUP_EXTENSION | wc -l)
    if [ $filenum -ge $BACKUP_MAX_FILES ]; then
        rm $(ls -1t $BACKUP_DIR/$CONTAINER | tail -n+$(($BACKUP_MAX_FILES++)))
    fi
}

backup_generate
if [ $? -ne 0 ]; then
    echo "Error generating backup."
    exit 1
fi

if [ -z $BACKUP_MAX_FILES ]; then
    remove_older
fi