Q: Log monitoring shell/cron script

Hi !

I have simple shell script being invoked from cron which monitors weird problem on ISPConfig - dovecot and postfix loosing connection with mysql db for user authentication (while mysql is 100% OK).

I short - dovecot monitoring works, postfix does not - its seems there is a bug in my grep.
Log lines:

Code:

Aug  9 08:51:21 mail postfix/smtpd[3233]: fatal: no SASL authentication mechanisms
Aug  9 08:51:21 mail postfix/smtpd[3234]: fatal: no SASL authentication mechanisms
Aug  9 08:51:21 mail postfix/smtpd[3235]: fatal: no SASL authentication mechanisms

Shell Script:

Code:

#!/bin/bash

NOW=$(date +'%Y-%m-%d %T')
LOGFILE='/var/log/anvcheck_services.log'
MAILERRLOG='/var/log/mail.err'

# Create log file if it doesn't exist.
if [ ! -f $LOGFILE ]; then
    touch $LOGFILE
    echo "$NOW : log file created" >> $LOGFILE
fi

if [ ! -f $MAILERRLOG ]; then
    exit 0
fi

ERRSTRING1="dovecot/|lda\|Fatal\|Internal\|error\|occurred"
ERRSTRING3="postfix/|smtpd\|fatal\|no\|SASL\|authentication\|mechanisms"

cat $MAILERRLOG | \
while read LINE
do
    echo "$LINE" | grep -q "$ERRSTRING1"
    if [ $? = 0 ]
    then
        echo "$NOW : Dovecot problem detected" >> $LOGFILE
        service dovecot restart
        mv $MAILERRLOG "$MAILERRLOG-$NOW"
        exit 0
    fi
done


cat $MAILERRLOG | \
while read LINE
do
    echo "$LINE" | grep -q "$ERRSTRING3"
    if [ $? = 0 ]
    then
        echo "$NOW : Postfix problem detected" >> $LOGFILE
        service postfix restart
        mv $MAILERRLOG "$MAILERRLOG-$NOW"
        exit 0
    fi
done

Thanks in advance !

 

In what way does it not work? What was the expected result of your code?
You get better help if you make the work of person helping you easier. I am not fond of deciphering strange code.

From what I understand of your code, this might work. Have not tested.

Code:

ERRSTRING3="postfix/smtpd.*fatal:"

Then use grep -E, like this:
echo "$LINE" | grep -E -q "$ERRSTRING3"

Do read this:
https://www.regular-expressions.info/

 

Scanning log file with grep (for specific Postfix error related to MySQL db user lookup) doesn't trigger true even if these error messages are presented in mail.err.
This works
ERRSTRING1="dovecot/|lda\|Fatal\|Internal\|error\|occurred"
This do not
ERRSTRING3="postfix/|smtpd\|fatal\|no\|SASL\|authentication\|mechanisms"
Although they both very similar. This is why I'm concluded there is a bug in ERRSTRING3 definition.

 

Get it worked, syntax error was in another part of script