Terraform CLI Extended

Description

This project is meant to enhance the Terraform CLI by providing the ability use dynamic git refs for module sources

A normal use case is when referencing terraform modules from an external repository where you want to take advantage from branching e.g. use different implementations for different environments (dev & prod)

Normally you would have to do something like this, as Terraform does not supprt dynamic values in the source parameter.

module "example" {
    source = "git::https://example.com/vpc.git?ref=master"
}

With Terraform CLI Extendedd you can implement it using a placeholder for the git ref

module "example" {
    source = "git::https://example.com/vpc.git?ref=<place_holder>"
}

The call terraform-ext.sh -m plan -p "<place_holder>" -r dev will temporarily replace the placeholder, execute the terraform command reset the ref to the placeholder

module "example" {
    source = "git::https://example.com/vpc.git?ref=dev"
}

HINT: You can use any valid git ref like branches, tags or commits for -r values

Available Flags

Flag	Description
-h	Displays the help window
-m	Specify the terraform command. Choose from init, validate, plan, apply, destroy
-r	Use with Git ref replacement Specify a Git ref which should be used to download modules from external repositories in code you have to use an unique placeholder like ?ref=
-p	Use with Git ref replacement The script searches for occurrences of ?ref=<your_placeholder> and replaces it with your -r value Do not use \ {backslash} in your placeholder
-w	Terraform workspace name if required
-b	Terraform backend config file
-v	Terraform variables file
-c	Flag for removing the .terraform/modules folder and re-pulling modules
-o	Use terraform plan files. Plan will output a terraform.plan file in the local directory Apply will requires a terraform.plan file in the local directory

Command examples

---

Command	Description
terraform-ext.sh -m plan -o	Performs normal Terraform plan and outputting the plan to the local directory as terraform.plan
terraform-ext.sh -m plan -o -p fancy_placeholder -r master	Performs a Terraform plan but all GIT refs matching the placeholder a replaced and referencing to the master branch
terraform-ext.sh -m apply -o	Apply a local terraform.plan file
terraform-ext.sh -m apply -o -p fancy_placeholder -r master	Applies a local terraform.plan file but GIT refs matching the placeholder are replaced to the master branch