需求描述

实现如下MySQL备份功能:

1、对MySQL库表schema 及数据进行定时备份
2、滚动删除指定日期(如30天)前的所有备份数据

测试脚本

vim /data/backup/scripts/MySQL_Backup.sh

#!/bin/bash

# Desc:
#   1. Implements all MySQL databases backup 
#   2. Implements Rolling delete data 30 days ago

set -x

USERNAME="DB_Backuper"
PASSWORD="DB_Backuper"
DBHOST="localhost"
PORT=3306

MySQL_BACKUP_DBLIST="db_1|db_2|db_3|db_4|db_5"
MySQL_STORAGE_BACKUP_PATH="/data/backup/data"
MySQL_BIN_PATH="/usr/bin"

Y_DIR=`(date "-d 0 day ago" +%Y)`
M_DIR=`(date "-d 0 day ago" +%Y%m)`
D_DIR=`(date "-d 0 day ago" +%Y%m%d%H%M)`

Y_LAST_DIR=$(date +%Y "-d -1 year")
TWO_YEARS="$Y_LAST_DIR|$Y_DIR"

# N days ago's data will be deleted
N=30

echo -e "*****************************************"
echo ">>>>>>>>>>>>>>>>>>>>>>> backup started on" `date +%Y/%m/%d--%k:%M:%S`;

for DB in `echo ${MySQL_BACKUP_DBLIST//|/ }`; 
	do

	mkdir -p $MySQL_STORAGE_BACKUP_PATH/$DB/$Y_DIR/$M_DIR/$D_DIR
	DB_BACKUP_PATH=$MySQL_STORAGE_BACKUP_PATH/$DB/$Y_DIR/$M_DIR/$D_DIR

	$MySQL_BIN_PATH/mysqldump --host=$DBHOST --user=$USERNAME --password=$PASSWORD --port=$PORT --opt --triggers --routines --single-transaction --set-gtid-purged=OFF $DB | sed 's/DEFINER=`[^`]+`@`[^`]+`/DEFINER=CURRENT_USER/g' > $DB_BACKUP_PATH/$DB.sql

	# Rolling delete data N days ago
	for YEAR in `echo ${TWO_YEARS//|/ }`;do
	    PATH_TOBE_CHECK=$MySQL_STORAGE_BACKUP_PATH/$DB/$YEAR
	    if [ -d $PATH_TOBE_CHECK ];then
	        find $PATH_TOBE_CHECK -type d -mtime +$N | xargs rm -rf
	    fi
	done
done;

echo ">>>>>>>>>>>>>>>>>>>>>>> backup ended   on" `date +%Y/%m/%d--%k:%M:%S` 
echo -e "*****************************************"

说明:

文本替换
for … in 语法中要求数据需要以空格分割, 这里需要对数据库列表进行文本替换
${MySQL_BACKUP_DBLIST//|/ }
注意}前有一个空格
当然也可以使用sed来做文本替换.

判断文件夹(或文件)非空
如果文件夹或文件为空,则在删除时会报错,这里只需要对已存在的文件(夹)做删除操作即可.
① 判断文件夹是否存在: if [ -d $PATH_TOBE_CHECK ]
② 判断文件夹不存在: if [ ! -d $PATH_TOBE_CHECK ]
③ 如果判断是文件类型, 只需要把"-d"参数替换为"-f"参数.