problem with findclass

Question

I have an iRule which uses the following statement    
   set myData [findclass [virtual] myClass]    
   where the class entries are as follows    
   class myClass {  
  "icmrdc2_80 field1 field2 field3"    
  "icmrdc2_8081 field1 field2 field3"  
  }    
   when the virtual name is icmrdc2_80, findclass always returns    
   "icmrdc2_8081 field1 field2 field3"However, if the class entries are as follows    
  class myClass {   
  "icmrdc_80 field1 field2 field3"    
  "icmrdc_8081 field1 field2 field3"  
  }    
  when the virtual name is icmrdc_80, findclass always returns the entry "icmrdc_80 field1 field2 field3"    
  How do I make the findclass always search for an exact match?

thanks,    
    Al

hoolio · Answer

Hello Al, 
  
 finclass does a hardcoded wildcard match of the string against each line of the datagroup.  I don't think there is a way around this.  Perhaps you could make a feature request through F5 Support to provide an option for glob or specific matching against just the first "field" of the datagroup.  In the meantime, you could use a for loop and getfield to perform an exact match against the class:

when RULE_INIT { 
  
     Create a test class (actually a list in this case).  This could also be defined as a class/datagroup. 
    set ::test_class [list {field1 value1} {field1* value1} {field2 value2} {field11 value11}] 
  
     Loop through the datagroup line by line. 
    foreach element $::test_class { 
  
        Log the current line. 
       log local0. "Current \$element: $element" 
  
        Compare the element against the string. 
        If the datagroup entry has a wildcard, it should be listed first in the string compare statement. 
       if {[string match -nocase [getfield $element " " 1] "field11"]}{ 
  
           Found a match, so log it and break out of the foreach loop. 
          log local0. "Matched \$element: $element.  Value: [getfield $element " " 2]. Exiting loop." 
          break 
       } 
    } 
 }

Log output:

Rule : Current $element: field1 value1 
 Rule : Current $element: field1* value1 
 Rule : Matched $element: field1* value1.  Value: value1. Exiting loop.

If you don't want wildcard matching, you can test with this version which doesn't have a wildcard in the datagroup:

when RULE_INIT { 
  
     Create a test class (actually a list in this case).  This could also be defined as a class/datagroup. 
    set ::test_class [list {field1 value1} {field2 value2} {field11 value11}] 
  
     Loop through the datagroup line by line. 
    foreach element $::test_class { 
  
        Log the current line. 
       log local0. "Current \$element: $element" 
  
        Compare the element against the string. 
        If the datagroup entry has a wildcard, it should be listed first in the string compare statement. 
       if {[string match -nocase [getfield $element " " 1] "field11"]}{ 
  
           Found a match, so log it and break out of the foreach loop. 
          log local0. "Matched \$element: $element.  Value: [getfield $element " " 2]. Exiting loop." 
          break 
       } 
    } 
 }

Rule : Current $element: field1 value1 
 Rule : Current $element: field2 value2 
 Rule : Current $element: field11 value11 
 Rule : Matched $element: field11 value11.  Value: value11. Exiting loop.

Aaron

al_carandang_11 · Answer

Got an answer from F5.  The value returned when there are multiple matches is arbitrary and depends on how the class gets loaded in memory. 
&nbsp;  
&nbsp; To solve the problem, the code should be written asset myData [findclass "[virtual] " myClass] 
&nbsp;  
&nbsp; -Al 
&nbsp;  
&nbsp;  &nbsp;

al_carandang_11 · Answer

Ran into some strange behaviour again.  If the statement isset Base [virtual]  
  set myData [findclass "$Base " myClass " "]  
  myData is always empty      
        
    -Al

al_carandang_11 · Answer

found the answer... I was specifying the " " separator in the last case wherease I wasn't specifying one in the first.

hoolio · Answer

Don't you need to refer to the class as ::class (or $::class in pre-9.4.2)? 
&nbsp;  
&nbsp; Aaron

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