iApp–How to manage and build iRules

Michael Earnhart is a PME on our new technology research (NTR) team. While he isn’t one of the ninja’s who lives in the dark and wears black, he certainly falls into the “always up for a debate” category. And he is good at tirelessly coming up with new ideas for our technology.

Michael’s, “How to use an iApp template to build and manage iRules” is certainly a diamond in the rough. By providing the tools and guidance, he has put together something that offers users a way to use an iApp to quickly and easily deploy and update iRules from a friendly a simple UI. This is useful to large organizations and hosting providers that need to instantiate the same iRule for multiple clients. The same method benefits iRules that may require frequent changes to variables, or for managing highly sophisticated rules.

How does it work? Well using Michael’s guidance, a user would first build an iRule template. This template is basically an iRule without the actual variable values defined. In their place is a reference tag that matches it to the data a user fills in via an iApp. The second step is building an iApp template to define the UI for users to provide their input values, with an instruction in the implementation section to call the iRules Preprocessor (IPP) after the variables are defined and an application service object (ASO) created. The IPP (TCL script) replaces the reference tags from the iRule template with the values provided by the user to produce an iRule.

If a user needs to update a variable of the iRule later they just open the ASO, make the change, and save it. They can also easily create multiple iRules based on the same template by rerunning the template with different inputs, easily building more than 90% of the iRule automatically.