adding/deleting class member by iRule

Currently classes are merely implemented as Tcl lists. So, you can manipulate the class members using the standard Tcl list commands.

 

 

lappend - add an element to the end of the list

 

linsert - insert an element into a list

 

lreplace - replace/delete elements of a list

 

lset - replace the value of an element of a list

 

Is there a way to save these changes to the class, or does it do so automatically?

 

 

Thanks,

 

Brian

No, there is currently not a way to save the class.

 

 

Also, I should add that in 9.0.3 we re-implemented the data structure behind a class, so that it is much faster and scalable. You can still use Tcl lists to manipulate the class, however, the class will then lose its efficiency.

 

 

We are also considering adding a set of commands that would allow one to manipulate the class. These commands would also support permanently saving the added/deleted members to the class.

 

iControl, Bigpipe, and GUI already have support for classes, including the ability for adding/deleting/finding/listing class and class members. They just don't have visibility to class members that are added to a class from within an iRule, but that's due to the fact that an iRule not being able to save the class.

 

Loc

Has this functionality been added yet? Thanks, Brian

Nope...

One thing I am testing -- it seems that I can log the contents of a class... Unfortunately the formatting isn't that useful... Is there a good doc or discussion thread on how to format the output to /var/log/ltm?

 

 

I am thinking about writing an iRule that collects all the URIs requested for a VIP into a two field class. (Field 1: URI Field 2: request count) Upon RULE_INIT it will dump this class to the log.

 

 

Three questions:

 

----------------

 

1) Is this possible?

 

2) Do you know of anyone who has already written this iRule?

 

3) Would this be too inefficient without the optimized class manipulation commands?

 

 

Thanks,

 

Brian

Well, this would be cool... I'm not sure about the approach though. Here are the problems:

 

a) log can only log one line at a time max 1024 chars.

 

b) RULE_INIT is a bit tricky to force to evaluate (it's only evaluated when a rule has been modified).

 

 

Another approach that I'm a little surprised no one has done yet is the following:

 

Create a dedicated tcp/http VIP. In the HTTP_REQUEST event, if the request is something like: "/vip_stat", then generate your payload into a variable and then use HTTP::respond to return the content. The same vip could report on other tcl statistics as well. If the request is invalid, simply use HTTP::respond to throw a 404. The vip would never really connect to anything on the backside. Then you could use curl or something to retrieve the status into a file from either the host or any other box...

 

You currently can modify a class/datagroup from an iRule. You will need to use either the session table or a Tcl array (this one is not a good option though as you need to be sure have logic to remove entries from the array otherwise it will grow forever).