It's not an unusual situation when you need to provide long-form non-Terraform-specific text configuration to your Terraform templates. On many occasions, you need to pass to Terraform a bootstrap script for your virtual machines, or upload large file to S3, or, another example, configure IAM policies.
Sometimes, these files are static, that is, you don't need to change anything inside them, you just need to read their contents inside Terraform template. For this use case, there is a file() function. You pass a relative path to your file as an argument to this function, and it will read its contents to whatever place you need.
Let's use this function to upload a public SSH key to EC2. Add the following ...
