检测mysql主从复制是否正常的shell脚本

#!/bin/bash

#主服务器
USERNAME=msandbox
PASSWORD=msandbox
EXPECTED_MASTER_HOST=127.0.0.1
EXPECTED_MASTER_PORT=27371

#从服务器
SLAVE_HOST=127.0.0.1
SLAVE_PORT=27372

MYSQL="mysql -u $USERNAME -p$PASSWORD "
MASTER="$MYSQL -h $EXPECTED_MASTER_HOST -P $EXPECTED_MASTER_PORT"
SLAVE="$MYSQL -h $SLAVE_HOST -P $SLAVE_PORT"

#查看主服务器状态
$MASTER -e 'SHOW MASTER STATUS\G' > mstatus
#查看从服务器状态
$SLAVE -e 'SHOW SLAVE STATUS\G' > sstatus

function extract_value {
FILENAME=$1
VAR=$2
grep -w $VAR $FILENAME | awk '{print $2}'
}

#主服务器的binlog 和position
Master_Binlog=$(extract_value mstatus File )
Master_Position=$(extract_value mstatus Position )

#从服务器上读取到的主服务器信息
Master_Host=$(extract_value sstatus Master_Host)
Master_Port=$(extract_value sstatus Master_Port)
#主从复制的进度
Master_Log_File=$(extract_value sstatus Master_Log_File)
Read_Master_Log_Pos=$(extract_value sstatus Read_Master_Log_Pos)

#从服务器的二个进程信息
Slave_IO_Running=$(extract_value sstatus Slave_IO_Running)
Slave_SQL_Running=$(extract_value sstatus Slave_SQL_Running)

ERROR_COUNT=0
#...
if [ "$Master_Host" != "$EXPECTED_MASTER_HOST" ]
then
ERRORS[$ERROR_COUNT]="the slave is not replicating from the host that it is supposed to"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi
#...
if [ "$Master_Port" != "$EXPECTED_MASTER_PORT" ]
then
ERRORS[$ERROR_COUNT]="the slave is not replicating from the host that it is supposed to"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi

if [ "$Master_Binlog" != "$Master_Log_File" ]
then
ERRORS[$ERROR_COUNT]="master binlog ($Master_Binlog) and Master_Log_File ($Master_Log_File) differ"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi

POS_DIFFERENCE=$(echo ${Master_Position}-$Read_Master_Log_Pos|bc)

if [ $POS_DIFFERENCE -gt 1000 ]
then
ERRORS[$ERROR_COUNT]="The slave is lagging behind of $POS_DIFFERENCE"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi

if [ "$Slave_IO_Running" == "No" ]
then
ERRORS[$ERROR_COUNT]="Replication is stopped"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi

if [ "$Slave_SQL_Running" == "No" ]
then
ERRORS[$ERROR_COUNT]="Replication (SQL) is stopped"
ERROR_COUNT=$(($ERROR_COUNT+1))
fi

if [ $ERROR_COUNT -gt 0 ]
then
EMAIL=myname@gmail.com
SUBJECT="ERRORS in replication"
BODY=''
CNT=0
while [ "$CNT" != "$ERROR_COUNT" ]
do
BODY="$BODY ${ERRORS[$CNT]}"
CNT=$(($CNT+1))
done
echo $SUBJECT
echo $BODY
echo $BODY | mail -s "$SUBJECT" $EMAIL
else
echo "Replication OK"
printf "file: %s at %'d\n" $Master_Log_File  $Read_Master_Log_Pos
fi