Piping Apache log through script - not working for error log

Question

I'm building a LAMP server for multiple users to practice web development using mod_userdir, and have written scripts to break out the access and error logs to log directories within the user's home directories.

The access_log.sh script is working fine (log lines get written both to the main server log file, and the user's log file), but error_log.sh is only updating the main log file. This is error_log.sh:

#!/bin/bash

IFS='
'

userlogfile=error.log
syslogfile=/var/log/apache2/cs-web_error.log

homedirs=`ls -d /home/*`

while read logline; do
    echo -e ${logline} >> ${syslogfile}
    #echo -e "writing ${logline} to ${syslogfile}" #TESTING

    for homedir in $homedirs; do
        userlogpath="${homedir}/logs/${userlogfile}"
        if echo $logline | grep ${homedir} > /dev/null; then
            echo -e ${logline} >> ${userlogpath}
            #echo -e "writing ${logline} to ${userlogpath}" #TESTING
        fi
    done
done

The logging config for Apache is:

CustomLog "| ${APACHE_LOG_DIR}/access_log.sh" common
ErrorLog "| ${APACHE_LOG_DIR}/error_log.sh"

If I uncomment the #TESTING statements, I get output like this when piping the error log through the script:

writing [Fri Sep 06 12:15:11 2013] [error] [client 193.61.230.178] PHP Parse error:
syntax error, unexpected 'select' (T_STRING) in /home/ginny/htdocs/test.php on line 12 
to /var/log/apache2/cs-web_error.log
writing [Fri Sep 06 12:15:11 2013] [error] [client 193.61.230.178] PHP Parse error:  
syntax error, unexpected 'select' (T_STRING) in /home/ginny/htdocs/test.php on line 12 
to /home/ginny/logs/error.log

... which shows that the grep statement is working. Also, running manually like this, the file is created and written to:

root@cs-web:~# ls -l /home/ginny/logs/
total 16
-rw-r--r-- 1 root root 2213 Sep  6 12:53 access.log
-rw-r--r-- 1 root root 9984 Sep  6 12:49 error.log

What I'm struggling to understand is why this works for the access log, and not for the error log - the only differences are:

root@cs-web:/var/log/apache2# diff access_log.sh error_log.sh
6,7c6,7
< userlogfile=access.log
< syslogfile=/var/log/apache2/cs-web_access.log
---
> userlogfile=error.log
> syslogfile=/var/log/apache2/cs-web_error.log
12a13
>     #echo -e "writing ${logline} to ${syslogfile}"
15,17c16,17
<         homedir=${homedir#/home/}
<         userlogpath="/home/${homedir}/logs/${userlogfile}"
<         if echo $logline | egrep "/(~|users/)${homedir}/" > /dev/null; then
---
>         userlogpath="${homedir}/logs/${userlogfile}"
>         if echo $logline | grep ${homedir} > /dev/null; then
18a19
>             #echo -e "writing ${logline} to ${userlogpath}"

Suggestions gratefully received.

konsolebox · Accepted Answer · 2013-09-09 11:50:39Z

1

Quote your variables properly and use arrays instead. readarray is also better than depending on word splits and possible generation through pathname expansion.

#!/bin/bash

#IFS=$'\n'  ## No longer needed.

userlogfile=error.log
syslogfile=/var/log/apache2/cs-web_error.log

readarray -t homedirs < <(ls -d /home/*)

while read logline; do
    echo -e "${logline}" >> "${syslogfile}"
    #echo -e "writing ${logline} to ${syslogfile}" #TESTING

    for homedir in "${homedirs[@]}"; do
        userlogpath="${homedir}/logs/${userlogfile}"
        if echo "$logline" | grep "${homedir}" > /dev/null; then
            echo -e "${logline}" >> "${userlogpath}"
            #echo -e "writing ${logline} to ${userlogpath}" #TESTING
        fi
    done
done

But if your version is earlier than 4.0, then just use the other method:

IFS=$'\n'
homedirs=($(ls -d /home/*))

I suggest that you also use the same concept with the other script for safety.

UPDATE

In your second script you no longer tried to trim $homedir with /home/ which means it's possible that if "$homedir" doesn't begin with /home/, $userlogpath would be <user>/logs/${userlogfile}", whereas in your first script it would still be /home/<user>/logs/${userlogfile}. Try to use these lines in your error_log.sh as well.

     homedir=${homedir#/home/}
     userlogpath="/home/${homedir}/logs/${userlogfile}"

edited Sep 9, 2013 at 11:50

answered Sep 6, 2013 at 14:01

konsolebox

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1 Comment

robhogg Over a year ago

Oh me of little faith - sorry about the earlier doubt, konsolebox - I tried your changes, and it's working. Have to say I don't really understand why that solves the problem, but it does. Than you.

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