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Chris_Phillips's avatar
Chris_Phillips
Icon for Nimbostratus rankNimbostratus
Feb 23, 2012

single vs multi element classes in irules

 

Howdy,

 

 

 

I wrote a bit of code on 10.2.0 which looped through a class and used scan to extract three variables:

 

 

 

foreach limit_element [class get ${static::limit_prefix}_dgl] {

 

scan $limit_element {%[^ ] %d/%d} limit_uri conn_limit conn_timeout

 

[...]

 

}

 

 

 

etc. With a class with ONE element, this chokes, as the $limit_element value is only the value itself, e.g. "200/1", not the attribute name as well. With MORE elements in the list, it works great, and $limit_element is "/login 200/1" . Similarly this looks to be reflected in bigip.conf contents, as extra brackets exist etc.:

 

 

 

class http_request_limit_dgl {

 

{

 

"/login" { "200/1" }

 

"/sample_uri" { "5/10" }

 

}

 

}

 

 

 

class t1_http_request_limit_dglxx {

 

"/login" { "200/1" }

 

}

 

 

 

Can anyone comment on this?

 

application delivery
dev
devops
iRules

4 Replies

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Feb 23, 2012
    If you need to loop through the datagroup to perform an operation with the key or value, you can use a class loop: 

    
    Save a class name to search through
   set class_name t1_http_request_limit_dglxx2

    Save a search ID for the datagroup
   set id [class startsearch $class_name]

    Loop through the class row by row
   while {[class anymore $class_name $id]}{

set element [class nextelement $class_name $id]
log local0. "\[class nextelement $class_name $id\]: $element"

 Perform some operation against the current datagroup key and/or value
scan $element {%[^ ] %d/%d} a b c
log local0. "scanned $element: $a, $b, $c"
   }
    Clean up the search
   class donesearch $class_name $id

    This works for a single line or multiple line data group. I think the reason your original rule isn't working as expected is that the name and value returned using class get against a single line data group is interpreted as a two element TCL list: {name} {value}, whereas a multiple line data group is interpreted as {name1 value1} {name2 value2}.

    Aaron
  • Chris_Phillips's avatar
    Chris_Phillips
    Icon for Nimbostratus rankNimbostratus
    Feb 24, 2012
    Yes, absolutely. I think the issue I have is how this is at all acceptable..? It's massively inconsistent.

     

     

    But you say that method will always present the data in a consistent way, whether it's one or more elements on a class? Worth a go... thanks
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Feb 24, 2012
    That does seem a bit buggy. If you are interested in finding out more about you could open a case with Support. If you do, can you reply with the case number so I can follow it?

     

     

    The class startsearch option worked as expected though so you should have a workaround.

     

     

    Thanks, Aaron
  • Chris_Phillips's avatar
    Chris_Phillips
    Icon for Nimbostratus rankNimbostratus
    Feb 24, 2012
    Yep, that does work, thanks for that. I'll see if I can something raised, that does seem pretty bizarre to me.