Terraform Console Examples for Debugging for_each Loops

This repository accompanies a YouTube tutorial demonstrating how to use the Terraform console to debug and understand for_each loops and the for syntax in Terraform.

What's Inside?

This repository provides a complex nested data structure written in HashiCorp Language (HCL), representing hypothetical resources and settings for various environments. These data structures are designed to mimic real-world use cases, helping you understand how you might work with similar structures in your own Terraform projects.

Objective

The goal is to demonstrate the use of Terraform console and for syntax to extract and manipulate data, which is particularly useful when working with for_each loops. This repository does not create any real infrastructure but serves as a sandbox for learning and debugging Terraform data structures.

Example

Consider this for expression:

{ for k, v in local.global_config.environments : k => v.vpc.subnets.*.id }

This expression is iterating over each environment in the global_config map. For each environment (k), it accesses the list of subnet IDs within the VPC configuration (v.vpc.subnets.*.id) and creates a new map where each key is the name of an environment, and its value is the list of associated subnet IDs.

Getting Started

1. Clone the repository:

   git clone https://github.com/iangrunt/terraform-console-example.git
   

2. Navigate to the directory:

   cd terraform-console-example
   

3. Create a main.tf file and wrap the contents of giant-mess.hcl in a locals block.

   vim main.tf
   

4. Start the Terraform console:

   terraform console
   

5. In the Terraform console, experiment with various for expressions and other Terraform functions on the data structures provided in the main.tf file.

Further Reading

Here are some links to the official Terraform documentation that explain these concepts in more detail:

• For expressions
• For_each loops
• Splat expressions

Prerequisites

• Terraform v1.0 or later.

Contribute

If you have suggestions for how this tutorial can be improved, feel free to open an issue or a pull request.