Avoid using absolute file paths in Terraform configurations executed in Terraform Cloud

Problem

With no changes in Terraform code, Terraform Cloud runs errored with errors related to files/directories missing.

E.g.

• On argument filename of aws_lambda_function resource
• On using templatefile function
• On using external data source

Cause

From Terraform Cloud document

Terraform Cloud performs Terraform runs in single-use Linux virtual machines, running on an x86_64 architecture.

The operating system and other software installed on the worker VMs is an internal implementation detail of Terraform Cloud. It is not part of a stable public interface, and is subject to change at any time.

As the implementation detail of Terraform worker VM can be changed at any time, users who have hard-coded absolute file paths in the Terraform configurations may face with errors on missing files/directories

Solution

• Avoid using absolute but relative file paths in Terraform configurations
• Avoid using named value path.cwd and use path.root or path.module instead. This is because path.cwd expands to an absolute file path while the others return safe, relative path.

Outcome

Terraform runs to be completed successfully

Additional Information

• https://www.terraform.io/language/expressions/references#filesystem-and-workspace-info