Mastering CloudForms Automation

Chapter 46. Argument Passing and Handling

Over the preceding chapters we have discovered several ways of calling Automate instances. In some cases we need to pass arguments into the instance’s method, but the way that we pass arguments into methods, and receive them from inside the method, varies depending on how the instance is called. We need to consider this if we’re writing code that can be called in several ways, such as from a button and/or from an API call.

In this chapter we’ll look at how we pass arguments into instances and how we retrieve them from inside the method. We will call the same instance (ObjectWalker) four ways, passing two arguments each time: lunch and dinner. We can use object_walker_reader to show us where the arguments can be read from inside our called method.

Case 1: Calling from a Button

For this first case we call ObjectWalker (via /System/Process/Request/Call_Instance) from a button. We create a button dialog that prompts for two text box fields (see Figure 46-1).

Figure 46-1. Simple dialog to prompt for input values

We then add the button to a button group anywhere.

If we click on the button and enter the values salad and pasta into the dialog boxes, we see the dialog values appear in $evm.root in the receiving method, indexed by the key name prefixed by dialog_:

~/object_walker_reader.rb | grep -P "lunch|dinner" | $evm.root['dialog_dinner'] ...