This guide describes how to define and use variables in your KCL function. Variables can simplify your composition function and reduce repetition in your code. You can define complex expressions as a variable and reference that variable throughout your function.

Define variables

To define a variable, use the = operator to assign a value. You can define two types of variables: a global, immutable variable or a mutable variable. Learn more at the KCL docs

# This is an immutable variable
myvar = "value"

# This is a mutable variable
_myothervar = "value2"

Variables are valid within the current scope. Below is an example of defining a new managed resource as a variable:

myresource = v1beta1.Instance {
    spec.forProvider = {
        region: "us-west-1"
    }
}

In KCL, you don’t need to specify the variable data type. KCL infers the type from the value.

Special variables

The items and the options variables are important required variables in your KCL embedded function.

KCL functions require the special items variable to capture the desired state of your resources and pass those changes to your control plane to create or change. The special options variables provides context specific information to use in your function.