What functionality does Terraform's `output` variable provide?

The functionality of Terraform's output variable is to display values from the Terraform state after execution. After running a terraform apply, outputs allow you to extract data from your Terraform-managed infrastructure. This data can include important information like IP addresses, resource IDs, or any other attribute that you may want to reference or share after deployment.

Outputs are especially useful in scenarios where you may be working with multiple Terraform modules or collaborating with team members. They enable you to provide a user-friendly way to access key data without needing to manually query the state file or know the specific attributes of the resources. Additionally, outputs can be utilized in automation scripts or as input to other infrastructure components, promoting reusability and streamlined workflows.

In contrast, defining dependencies is managed through resource relationships rather than output variables. Setting environment variables is typically done outside of Terraform execution, usually in the shell or CI/CD pipeline. Logging changes is handled by Terraform's command output and state management rather than through outputs, which specifically focus on presenting information post-deployment.