For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

dlg_23340's avatar
dlg_23340
Icon for Cirrus rankCirrus
Nov 18, 2011

[class exists $redir_class]

Hello, all. I have an irule that needs to check if a class exists, then if it does, pull a record from it. If not, it should do nothing. in this case, the value contained in redir_class does not ex...
application delivery
dev
devops
iRules
George_Watkins_'s avatar
George_Watkins_
Historic F5 Account
Nov 18, 2011
Hi David,

It looks like you're almost there. One thing that I think may be throwing you off is the logging messages. The curly braces around your log commands will prevent variable substitution and command execution. Here is the iRule and datagroup I used to test with. 

ltm data-group internal /Common/test_vars {
    records {
        /var1 {
            data 4
        }
        /var2 {
            data 8
        }
    }
    type string
}

ltm rule /Common/test_vars_class_exists_2156869 {
when HTTP_REQUEST {
  set redir_class test_vars

  if { [class exists $redir_class] } {
    log local0. " [class match -value -- [HTTP::uri] starts_with $redir_class]"
  } else {
    log local0. " class $redir_class does not exist"
  }
}
}

Here are the results I got while testing various URIs:

http://test-http-vs/var1 => Nov 18 07:35:42 tmm info tmm[14987]: Rule /Common/test_vars_class_exists_2156869 :  4
http://test-http-vs/var2 => Nov 18 07:35:49 tmm info tmm[14987]: Rule /Common/test_vars_class_exists_2156869 :  8
http://test-http-vs/foo1 => Nov 18 07:35:55 tmm info tmm[14987]: Rule /Common/test_vars_class_exists_2156869 :

-George