Dear syslog-ng users, The following text was written on my blog, but I'm reposting it here for a wider audience to read: As of now the development of the generic rewrite feature has been completed in one of my private git repositories. The new code uses PCRE and I'm somewhat undecided how to move forward with PCRE. For those who might not know PCRE is an implementation of regular expressions and is an acronym for "Perl Compatible Regular Expressions". PCRE adds a lot more features and seems to perform better than its POSIX equivalent. So the situation is as follows: * various filters use POSIX regexps * rewrite uses PCRE This is not a very consistent combination, thus I'm planning to add PCRE support for filters too. The only question is whether it is needed to have two independent regexp styles in syslog-ng in the long run. If I decide that one of them is enough, then I'd deprecate POSIX style regexps in filters and wouldn't implement POSIX in rewrite rules. This combination would yield a syslog-ng that would give warnings when POSIX-style regular expressions are in use and in a forthcoming release I'd change the default regexp style to PCRE, and yet another syslog-ng release later, I'd phase out POSIX completely. If the decision is to keep them both in the long run, it would mean that I'd need to implement POSIX style regexps for rewrite rules as well. This would probably the least intrusive for users, but also a lot more work. Also, this would allow adding other filtering options like globbing or prefix search. What do you think? Is the addition of modular search algorithms worth it? -- Bazsi
I prefer PCRE, have no problem converting to PCRE only. I've been told PCRE runs faster, a definite consideration for high volume sites. We've gone out of our way to simplify regexes to avoid performance hits, with a faster expression parser, I could back down on optimizations. What other modules do you foresee? Kevin
* Balazs Scheidler <bazsi@balabit.hu> [2008-06-30 16:42]:
Dear syslog-ng users,
The following text was written on my blog, but I'm reposting it here for a wider audience to read:
As of now the development of the generic rewrite feature has been completed in one of my private git repositories. The new code uses PCRE and I'm somewhat undecided how to move forward with PCRE.
For those who might not know PCRE is an implementation of regular expressions and is an acronym for "Perl Compatible Regular Expressions". PCRE adds a lot more features and seems to perform better than its POSIX equivalent.
So the situation is as follows: * various filters use POSIX regexps * rewrite uses PCRE This is not a very consistent combination, thus I'm planning to add PCRE support for filters too. The only question is whether it is needed to have two independent regexp styles in syslog-ng in the long run.
PCRE only! Less hassle for you and less confusion for the users. PCRE is superior to POSIX regexps in several ways, so who needs POSIX REs when he can use PCRE these days anyway? :) -- Regards, Wolfram Schlich <wschlich@gentoo.org> Gentoo Linux * http://dev.gentoo.org/~wschlich/
On Fri, 2008-07-04 at 12:16 +0200, Wolfram Schlich wrote:
* Balazs Scheidler <bazsi@balabit.hu> [2008-06-30 16:42]:
Dear syslog-ng users,
The following text was written on my blog, but I'm reposting it here for a wider audience to read:
As of now the development of the generic rewrite feature has been completed in one of my private git repositories. The new code uses PCRE and I'm somewhat undecided how to move forward with PCRE.
For those who might not know PCRE is an implementation of regular expressions and is an acronym for "Perl Compatible Regular Expressions". PCRE adds a lot more features and seems to perform better than its POSIX equivalent.
So the situation is as follows: * various filters use POSIX regexps * rewrite uses PCRE This is not a very consistent combination, thus I'm planning to add PCRE support for filters too. The only question is whether it is needed to have two independent regexp styles in syslog-ng in the long run.
PCRE only! Less hassle for you and less confusion for the users. PCRE is superior to POSIX regexps in several ways, so who needs POSIX REs when he can use PCRE these days anyway? :)
Great to know. In the meanwhile I have been confronted with the problem of providing syslog-ng binaries for 24 platforms that we support today. Adding a new build dependency (glib >= 2.14 and pcre in this case) is a _lot_ of work. So I've decided to support them both in the long run, implemented the glue layer that will work with both RE implementations, but for now only POSIX regexps are supported. I hope to readd PCRE again once I can get this release out. -- Bazsi
participants (3)
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Balazs Scheidler
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K K
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Wolfram Schlich