[syslog-ng] How to convert syslog-ng logs into xml format

[Evan Rempel]

One of the chalenges you will face with XML and syslog is that XML can not be validated until
all of the input has been XML parsed. If you have a 1GB XML file, your XML parser will probably
read the entire thing into RAM. Perhaps that works for you, but with our 4GB log file, the XML
parsing and internal data storage overhead, this could easily consume 8GB of RAM.

When you indicate that you need to put this on the WEB, you will find that XML of large data
will bring your web server to its knees. Parsing through 1GB of data to return a line or two
will be very CPU intensive, and on a clickable (web) setup, this will be repeated often.

I also think you someone at your site has a fever, and I hope they seek some prfessional
advice rather than self-diagnosing the issue :-)

Evan.

Padmanabhan, Rajeesh (GE Healthcare) wrote:
>  Hi Alex,
> 
> Thanks a lot for your quick response. Infact my role here to act as
> 'Tech-monkey' :)
> I have a syslog-ng clients & server. Clients should be able to transfer
> logs in xml format to server. & server stores in a local location(xml
> file). Idea is to upload this to web & backup, which can read data in
> xml fomat. 
> Could you please explain me to create a template that generate logs in
> xml format.
> 
>  Cheers!
> Rajeesh
> 
> -----Original Message-----
> From: syslog-ng-bounces at lists.balabit.hu
> [mailto:syslog-ng-bounces at lists.balabit.hu] On Behalf Of Alexander
> Clouter
> Sent: Sunday, February 11, 2007 4:21 PM
> To: Syslog-ng users' and developers' mailing list
> Subject: Re: [syslog-ng] How to convert syslog-ng logs into xml format
> 
> Hi,
> 
> Padmanabhan, Rajeesh (GE Healthcare) <Rajeesh.Padmanabhan at ge.com>
> [20070211 15:40:27 +0530]:
> 
>>Hi All,
>> 
>>I need to convert syslog-ng logs into xml format. Could you please 
>>help me to do the same. If someone can send me a sample format, would 
>>be great.
>> 
> 
> Oh dear...sounds like someone caught 'xml fever', it happens to all of
> us at some stage and we usually recover from the illness when its too
> late and the project is already using it...
> 
> XML is something thats abused more often than its used properly.  Its
> useful if you have two rather different systems that have no common data
> exchange mechanism between them and so XML is used as a 'common' format.
> Bear in mind that this means is at both ends you have to get programming
> tech-monkeys to write scripts to convert the data to XML and then back
> from XML into another format.  In situations like this you do not care
> that it could take two weeks of solid CPU crunching to import the data,
> just as long as it gets there...
> 
> Now as you have not given much detail about why you need the files in an
> XML format or what you plan on doing with the files the follow format is
> probably
> 'suitable':
> 
> <?xml version="1.0" encoding="UTF-8"?>
> <syslog>
>   <message>first syslog message</message>
>   <message>second syslog message</message>
>   ...
> </syslog>
> 
> I'm finding it hard to think of a situation where XML and syslog data
> would be a good idea given that its rather easy to parse and store
> syslog data already.  People want to archive and easily search (usually
> with nothing more than grep) their syslog logs and in an XML format
> searching your logs *will* slow down by at least a factor of 1000.
> 
> A far more suitable format, if flat text files is not good enough, is a
> SQL database; probably the only real useful application of an SQL
> database[1].
> 
> I'm unsure how to help you recover from your XML fever, it was difficult
> for me to grow out of.  I learn from my mistakes and unfortunately for
> me when you base a project around XML the mistakes (for me at least) do
> not have an effect till much later on.  There is nothing on the Internet
> as suggested reading but I am happy to discuss this off list if you want
> to.
> 
> I did some digging around to try to see if there was anything commercial
> doing this and found[2] something and was shocked at how they were doing
> it...its a bad schema and seems to be a solution to something that is
> not actually a problem.
> 
> *Everything* that deals with logging data should support syslog built
> logfiles (you might need to use syslog-ng with its template() command to
> structure the logfile to be in a format that the import engine expects
> though), if it does not you should look for some other software.  My gut
> feelings tell me this is an internal homebrew project though..
> 
> I hope the 'fever' breaks soon :)
> 
> Cheers
> 
> Alex
> 
> [1] thats another rant of mine though :) [2]
> http://www.kiwisyslog.com/kb/idx/4/125/article/
> 
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