Solving the Terraform Interactive Input Issue with Root Module

Discover why `Terraform` interactive input may not work with the root module and learn effective solutions to resolve it.
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Understanding the Terraform Interactive Input Issue

If you're working with Terraform, you may have encountered a situation where the interactive input prompts for your variables aren’t functioning as expected, particularly with root modules. This can be frustrating, especially if you're trying to set up your infrastructure seamlessly. Here’s what you need to know to effectively solve this issue.

The Problem at Hand

Scenario Overview

In your setup, you're using a hierarchical module structure where:

Root Module (R1) calls Child Module (C2) which, in turn, calls Child Module (C1).

You attempt to run the terraform apply command with the -input=true flag expecting Terraform to prompt you for missing inputs.

Encountered Error Message

When executing the command, you received the following error:

[[See Video to Reveal this Text or Code Snippet]]

This indicates that the expected input for ProjectName within your child module isn’t being set properly via the root module, leading to failure.

Analyzing the Solution

Key Considerations

Root Module Input Variables: Only root module input variables can be directly set during terraform apply using interactive prompts. Child module variables must be explicitly passed through the module block in the root module.

Input Variable Management: The -input=true flag is useful but is designed primarily for simple scenarios or initial setups, thus may not handle more complicated structures like yours well.

Recommended Actions

1. Declare Input Variables in the Root Module

You need to define the required variables at the root level. Here is an example of how you could structure your root module to include the necessary variable:

[[See Video to Reveal this Text or Code Snippet]]

In this configuration, you're correctly passing the test variable to the child module.

2. Create a .tfvars File

[[See Video to Reveal this Text or Code Snippet]]

Now, when invoking Terraform, you can simply use the command:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By redefining how you manage your input variables at the root level and adopting the use of a .tfvars file, you can effectively solve your issue with interactive input in Terraform. This method not only streamlines your workflow but also ensures that your Terraform configurations are set up correctly, paving the way for smooth infrastructure deployments.

By following these organized steps, you'll be able to overcome the limitations of interactive prompts and better manage your module dependencies in Terraform. Happy coding!