Parameters to iRules?

What's the best way to pass parameters to iRules?

 

 

I'm thinking of an iRule which will have a couple of parameters -- integer values which will control behavior. I'd like to figure out the best way to manage these.

 

 

I've seen a lot of iRules set such parameters as global variables in a RULE_INIT handler. However, if this method is used, tuning the parameters requires modifying the program. This doesn't seem like good practice.

 

 

I'm thinking of putting the parameters in a string data group. The iRule would look these up to determine the current policy.

 

 

My questions are:

 

 

- Will this work? Is a data group consulted dynamically, or will the iRule need to be recompiled anyway every time the data group changes?

 

 

- Is this a good way to do this? Will using the data group add an enormous amount of overhead?

 

 

- Has anybody else tried this, or any other method other than hard-coding the values in the iRule?

 

 

Craig