Forum Discussion

Anton_Koldaev_2's avatar
Anton_Koldaev_2
Icon for Nimbostratus rankNimbostratus
Feb 13, 2016

How to read class value by key?

BigIP LTM 11.5.1

I have a data group type string. And I have key-value pairs inside.

Data group name: 

test_dg

String Records:

key1 := value1
key2 := value2

How can I read "test[key1]" to get value1?

Will the following work?

set first_value [ class match --name -- "key1" equals test_dg ]
set second_value [ class match --name -- "key2" equals test_dg ]

application delivery
BIG-IP
devops
iRules
  • VernonWells's avatar
    VernonWells
    Feb 13, 2016
    set first_value [class lookup key1 test_dg]
set second_value [class lookup key2 test_dg]

    As the documentation states, this is equivalent to:

    set first_value [class match -value key2 equals test_dg]
set second_value [class match -value key2 equals test_dg]
  • VernonWells's avatar
    VernonWells
    Icon for Employee rankEmployee
    Feb 13, 2016
    set first_value [class lookup key1 test_dg]
set second_value [class lookup key2 test_dg]

    As the documentation states, this is equivalent to:

    set first_value [class match -value key2 equals test_dg]
set second_value [class match -value key2 equals test_dg]
    • Anton_Koldaev_2's avatar
      Anton_Koldaev_2
      Icon for Nimbostratus rankNimbostratus
      Feb 13, 2016
      Actually documentations as documenation states it'll return 0 or 1 but not the actual value: ``` The return value depends on the option specified. If no option was specified, the return value is 1 for a match and 0 for a no-match ```
    • VernonWells's avatar
      VernonWells
      Icon for Employee rankEmployee
      Feb 13, 2016
      That's if "class match" is used without any options. As I say, "class lookup" is equivalent to "class match -value", so an option is supplied, namely '-value'.
  • VernonWells's avatar
    VernonWells
    Icon for Employee rankEmployee
    Feb 13, 2016

    To demonstrate, I did the following:

     tmsh list ltm data-group internal test
  ltm data-group internal test records { abc { data 123 } def { data 456 } } type string
 tmsh list ltm rule test01 
  ltm rule test01 {
      when HTTP_REQUEST {
          set u [findstr [HTTP::path] / 1]
          set v [class lookup $u test]

          log local0. "With request-uri path = ([HTTP::path]), first element = ($u), value = ($v)"
      }
  }

    A few log entries:

     Rule /Common/test01 : With request-uri path = (/abc), first element = (abc), value = (123)
 Rule /Common/test01 : With request-uri path = (/def), first element = (def), value = (456)
 Rule /Common/test01 : With request-uri path = (/hij), first element = (hij), value = ()