pet-sounds is an application that uses a few intermediate HCL2 concepts to decode a configuration file and output some information about various pets.
pet.go and pets.hcl contain all the interesting code.
"Partial Decoding" is an extremely powerful concept in HCL decoding. It allows you to create configurations that are self referential, where one decoding step relies on another.
In our case, we'll use them to make the pet block generic, with a type field that determines what kind of pet it is. The characteristics block inside of pet is still type safe, with dog and cat blocks with unique fields that cannot be used in with wrong type of pet.
Variables are also useful for making HCL more dynamic.
In our case, we'll use a nested variable that can load certain information from the environment: env.CAT_SOUND for example.
Functions can be made that are custom to your HCL decoding domain. These allow for even more complicated and flexible HCL config files.
In our case, we'll create a random function that picks a random string from the inputs provided. Then we'll use that function to express our domain specific knowledge about the fickleness of cats.
Ink the cat from the configuration file is a real cat and he loves occupying desk space while you're trying to program.
