Templates

expected time	requirements
45 minutes	A computer with Terraform installed, terraform knowledge.

Goal: Use Templates to customize your usage of Terraform.

Explanation

Sometimes, you want Terraform to save a file with details from a Terraform run, such as an IP address. Terraform offers many functions one of which is the templatefile function.

Howto

These templates can be used in (for example) remote_file or local_file.

Here is an example to store an IP address of hosts managed by Terraform:

inventory.tf:

resource "local_file" "inventory" {
    content  = templatefile("templates/inventory.tpl", { ip = data.azurerm_public_ip.ipaddress.ip_address })
    filename = "${path.module}/inventory"
}

templates/inventory.tpl:

${ip}

Demo

Have a look here.

Assignment

You can start using this Terraform configuration. (Remember: az login, terraform init)

Please have Terraform write an ssh configuration listing the host managed by Terraform and sets the user to the user that’s specified in the input variables. Use this format:

Host ${ip}
  User ${username}

A GCP example to get you started.

Questions:

How can you pin the version of local_file?
Do you know a use case for using templates?
Will the local_file be remove when running terraform destroy?

Conclusion

You can use generated content or input variables to create file, both locally and remote.

learn-terraform