#!/usr/bin/env bash
#ported from http://dev.mysql.com/doc/refman/5.0/en/backup-policy.html (second comment)
#@author tomfmason@gmail.com

BINLOGPATH=/var/log/mysql
BINLOGNAME=mysql-bin
ARCHIVES=/var/backups/mysql
ARCHIVEPATH=$ARCHIVES/$(date +%Y-%m-%d)
mkdir -p $ARCHIVEPATH

function setReadable {
    chmod o+rx $BINLOGPATH
    chmod o+r $BINLOGPATH/*
}

function unsetReadable {
    chmod o-r $BINLOGPATH/*
    chmod o-rx $BINLOGPATH
}

function copyBinlogs {
    setReadable;
    for FILE in `cat $BINLOGPATH/$BINLOGNAME.index`; do
        if [ ! -f $ARCHIVEPATH/$FILE.gz ]; then
            cp $FILE $ARCHIVEPATH
            gzip $ARCHIVEPATH/$FILE
        fi
    done
    unsetReadable;
}

function flushLogs {
    mysqladmin -u root -p'password' flush-logs
    copyBinlogs;
}

function resetLogs {
    $YESTERDAY=$(date -d "yesterday" +%F)
    mysql -u root -p'password' -e "PURGE BINARY LOGS BEFORE '$YESTERDAY 23:59:58';"
}

function removeOldLogs {
    DATE=$(date -d "-3 days" +%F)
    if [ -d $ARCHIVES/$DATE ]; then
        rm -rf $ARCHIVES/$DATE
    fi
}

if [ $(date +%H) == "00" ]; then
    mysqladmin -u root -p'password' stop-slave
    copyBinlogs;
    flushLogs;
    resetLogs;
    mysqladmin -u root -p'password' start-slave
    removeOldLogs;
fi