Dockerfile that stored in repository is used for building Docker image that contains terraform tool installed.
Circle CI config is used for automatic build & pushing Docker image to repository.
Terraform is an open source Infrastructure as Code tool, created by HashiCorp.
A declarative coding tool, Terraform enables developers to use a high-level configuration language called HCL (HashiCorp Configuration Language) to describe the desired “end-state” cloud or on-premises infrastructure for running an application. It then generates a plan for reaching that end-state and executes the plan to provision the infrastructure.
To pull docker image use following command: For JFrog:
docker pull tictrac.jfrog.io/tictrac/terraform:<tag>