#!/bin/bash

# Backs up MySQL databases with zero downtime using Percona Xtrabackup.
# Stores 30 days worth on Amazon s3.

# These {{ double bracket }} things are Ansible/Jinja (ansible-vault) variables.
# Fill them in for your own usage.
MYSQLROOT=root
MYSQLPASS="{{ mysql_root_pass }}"
S3BUCKET={{ mysql_backup_bucket }}
BACKUP_DIR={{ mysql_archive_path }}
TIMESTAMP=$(date +"%Y-%m-%d_%H-%M-%S")

# Performance tuning
NUM_THREADS=4
USE_MEMORY={{ (ansible_memory_mb.real.total * 0.25) | int }}M

BACKUP_COMMAND="/usr/bin/innobackupex --user=${MYSQLROOT} --password=${MYSQLPASS} --no-timestamp ${BACKUP_DIR}/latest/ --parallel=${NUM_THREADS} --use-memory=${USE_MEMORY}"

CURRENT_ARCHIVE="${BACKUP_DIR}/mysql_${TIMESTAMP}.tar.gz"

echo "= Remove previous backup ------------------------------------------------"
rm -rf ${BACKUP_DIR}/latest/*

echo "= Ensure file permissions are intelligent -------------------------------"
chmod -R 700 ${BACKUP_DIR}

echo "= Back that SQL up... ---------------------------------------------------"
${BACKUP_COMMAND}

echo "= Prepare backup for immediate use --------------------------------------"
${BACKUP_COMMAND} --apply-log

echo "= Compress mysql archive ------------------------------------------------"
tar czf ${CURRENT_ARCHIVE} -C ${BACKUP_DIR}/latest/ ${BACKUP_DIR}/latest/*

echo "= Upload archive to s3 --------------------------------------------------"
s3cmd put -f ${CURRENT_ARCHIVE} s3://${S3BUCKET}/

echo "= Remove 30 day old LOCAL backups ---------------------------------------"
ls -1tr ${BACKUP_DIR}|head -n -30|xargs -d '\n' rm -rf --

echo "= Remove 30 day old s3 backups ------------------------------------------"
s3cmd ls s3://${S3BUCKET} | while read -r line;
  do
    createDate=`echo $line|awk {'print $1" "$2'}`
    createDate=`date -d"$createDate" +%s`
    olderThan=`date -d"-$2" +%s`
    if [[ $createDate -lt $olderThan ]]
      then
        fileName=`echo $line|awk {'print $4'}`
        echo $fileName
        if [[ $fileName != "" ]]
          then
            s3cmd del "$fileName"
        fi
    fi
  done;

echo ""
echo "MySQL backup done!"