Resolving Inconsistent Conditional Result Types in Terraform with Locals Templatization

Learn how to fix the `Inconsistent Conditional Result Types` error in Terraform when using locals with conditionals. This detailed guide breaks down the problem and offers effective solutions.
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Resolving Inconsistent Conditional Result Types in Terraform with Locals Templatization

When working with Terraform, you might come across the frustrating Inconsistent conditional result types error, especially when using locals templating. This issue typically arises when conditional statements yield object types that don't align in structure. Let's delve into this problem and explore practical solutions to effectively resolve it.

Understanding the Problem

Example Situation:

Your current code has two local templates—msr_launchpad_tmpl and mke_launchpad_tmpl. The inconsistency arises when msr attributes are defined differently in these templates, impacting the conditional logic used to set the launchpad_tmpl variable.

Here’s the conflicting section in your code:

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

The Error:

When you execute a plan, Terraform throws the following error saying that the true and false result expressions must have consistent types. The msr attributes differ across these two statements, causing the type mismatch.

Solution: Making Object Types Compatible

To ensure compatibility between the two object types, you'll need to adjust the structure of your msr attributes. Here are a couple of approaches you can implement:

1. Setting Default Values for msr in Both Templates

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

Adding these attributes ensures that both local variables have consistent types, enabling Terraform to process them correctly.

2. Using a Combined Object Container Approach

Another effective method is to encapsulate both templates into a single object container. This allows you to maintain the specificity of each template while allowing Terraform to easily identify the differing types:

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

This adjustment helps Terraform see both types distinctly, thus they can be validated without triggering the type error.

Important Considerations:

Conclusion

Encountering the Inconsistent Conditional Result Types error can be a stumbling block for many Terraform users. By ensuring object types remain consistent through careful structuring of your locals and applying the solutions outlined above, you can effectively sidestep these issues and ensure smooth execution of your Terraform configuration.

Adjusting your local template configurations will lead to a successful terraform plan and apply, allowing you to proceed with your infrastructure changes seamlessly.

By applying these best practices, you can build more robust Terraform templates that reduce the likelihood of type mismatch errors, leading to a smoother development experience.