[syslog-ng] patterndb - user defined parsers

Martin Holste mcholste at gmail.com
Sun Nov 27 17:51:09 CET 2011


Have you tried to solve this using the current conditionals available?

On Sun, Nov 27, 2011 at 12:27 AM, Evan Rempel <erempel at uvic.ca> wrote:
>
> It would be useful to permit users to define parsers in the patterndb.
> For example, in our environment, by policy we user a special set and order of characters of our
> administrators log into hosts and administer them. It would be useful to define a parser of
>
> @SYSADMIN@ that would match only our sysadmin accounts.
> We could then use this parser in the patterndb to take some action such as sending
> a message to the administrators about the event.
>
> Another example would be to create parser for @LOCALIP@ that matches my organizaions IP space.
> That way a set of rules can be defined using @LOCALIP@ for some kind of alerting, and then any
> organization could redifine the @LOCALIP@ and use all of the goodness that some third party had created for
> monitoring logs like an intrusion protection system.
>
> Current parsers can be described as
>
> QSTRING
>  - match opening char
>  - while not closing char, keep looking
>
> ESTRING
>  - while not end string, keep looking
>
> NUMBER
>  - while digit keep looking
>
> So it seems that general parsers could be constructed  with two styles of matching, and
> then concatenating the together.
>
> 1. While in set of characters [some list of characters]
> 2. While not in set of characters [some list of characters]
>
> I would call these
> INSET to match 1 or more of a set of characters, unless a #-# were specified, then a minimum to a maximum would be required.
> OUTSET to match 1 or more of anything except the characters, unless a #-# were specified, then a minimum to a maximum would be required.
> (perhaps a count of + or * could be used to specify 1 or more and 0 or more respectively)
>
> and then limit the count of such occurrences so that you could build the @IPv4@ parser as
>
> @INSET::123456789*1@@INSET::0123456789:0-2 at .@INSET::123456789:1@@INSET::0123456789:0-2 at .@INSET::123456789:1@@INSET::0123456789:0-2 at .@INSET::123456789:1@@INSET::0123456789:0-2@
>
> and @NUMBER@ would be
> @INSET::123456789:1@@INSET::0123456789@
>
> @FLOAT@ would be
> @INSET::0123456789.@
>
> Then a user could make
> <parser name="THOUSAND">@INSET::,:0-1@@INSET::0123456789:3@</parser>
> <parser name="MONEY">$@INSET::123456789:1-3@@THOUSAND:::*@. at INSET::0123456789:2@
>
> This is kind of like inventing regular expressions :-(
>
> I'm not sure how well this fits into the radix tree matching structure, but I wanted to start this discussion.
>
> Given the MONEY example, I think it is obvious that there needs to be a way to specify repeating groups of "something"
>
> Let the discussion begin!
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