On Fri, 2009-12-18 at 17:39 +0100, ILLES, Marton wrote:
On Tue, 2009-12-15 at 13:00 -0600, Martin Holste wrote:
This is an awesome start, and I'm big into patterndb so this is really encouraging. Off the bat, I'd say that it would be more helpful if the <values></values> tags were populated with the .dict values that are being extracted so that you can construct output patterns properly.
The <values></values> could be use to specify additional values which you want to set, but do not appear in the message itself. For example if you want to classify login messages, but for a certain message the username does not appear, but you know that this message reports a specific username. This case you can use the <values> to assign the .dict.username variable (for example) to that specific user and latter you can be sure that it exists.
I am still not sure if I completely understand your suggestion...
Along with that, if you have a different name for every .dict value extracted, it becomes labor-intensive to capture them in your output template. I prefer a method in which I have arbitrarily capped the number of values to be extracted to be six strings, six integers. I then label the values I extract as s0-s5 and i0-i5. That way I only need one template for all patterns extracted. Separating the strings and integers makes database insertion easy because my tables then look like <header columns> MSG, pattern_class_id, pattern_rule_id, i0 .. i5, s0 .. s5. Now searching for fields becomes possible if you know what field belongs to what pattern rule ID. I also prefer to have the rule ID's as integers to keep my DB columns smaller.
The reason for using UUID was to have the ability to provide global unique ids, simple integers would be hard to maintain. I was also thinking using OIDs for IDs, but UUID was an easier choice. Technically you can use simple integers or any other string as syslog-ng currently does not check it. I will think about it... :)
Using integers would be also better because of DB indexing purposes. If you want to use integers, you can than assign a <value name="my_id">42</value> as a work-around to each pattern and latter use "my_id" in your templates.
Here's an example for a Cisco FWSM deny and NAT translation teardown messages that I've been using:
<ruleset name="FWSM" id='2'> <pattern>%FWSM</pattern> <rules> <rule provider="local" class='2' id='2'> <patterns> <pattern>Deny@QSTRING:i0: @src@QSTRING:s0: :@@IPv4:i1:@/@NUMBER:i2:@ dst@QSTRING:s1: :@@IPv4:i3:@/@NUMBER:i4:@ by access-group @QSTRING:s2:"@</pattern> </patterns> </rule> <rule provider="local" class='3' id='3'> <patterns> <pattern>Teardown@QSTRING:i0: @connection @NUMBER::@ for@QSTRING:s0: :@@IPv4:i1:@/@NUMBER:i2:@ to@QSTRING:s1: :@@IPv4:i3:@/@NUMBER:i4:@ duration@QSTRING:s2: @bytes @NUMBER:i5:@</pattern> </patterns> </rule> </rules> </ruleset>
I prefer using more meaning-full names as this way you can normalize your logs, so that it wont matter if it is a PIX, iptables etc. log message, you can always refer to the source/destination address with it's name. It requires to store different type of logs in different tables, but you can freely change your application without changing your log processing scripts.
You can also combine these to methods to use meaningful names in patterns and using <values> you can assign to numbered values, like this:
<value name="s1">${.dict.source_ip}</value>
Of course it would require a bit more memory and CPU cycles. Of course you are free to name your values as you want. I think it is really a question on the patterns we try to build and distribute. Maybe I can add a rewrite mechanism to pdbtool which would rename the pattern names to numbered value names. So this way we can publish patterns with meaningful names and anyone can latter rename the patterns for numbered names. Would it fit your needs?
I guess it'd be simpler to reuse the numbered "match" support in syslog-ng, just what the regexps use. You can reference them using $1 .. $255 and it is quite simple to use them, I've almost created a patch, but at the end I didn't. With the new NVTable code, it could even use the same memory and store only a reference: log_msg_set_match_indirect(msg, index, ...) -- Bazsi