Add scripts to easily destroy tfstate backend (#33)

* Add scripts to easily destroy tfstate backend

* Improve annotations

* Address CR

* Fix formatting

* Use variable for force_destroy

* remove vim typo

* Update instructions

aws/tfstate-backend/Makefile

@@ -0,0 +1,7 @@
+## Initialize the configuration (should only be run once)
+init:
+	@scripts/$@.sh
+
+## Destroy the configuration (only works if `force_destroy=true`)
+destroy:
+	@scripts/$@.sh

aws/tfstate-backend/README.md

@@ -1,26 +1,29 @@
 # Bootstrap Process
 
-Run this process the very first time you setup the tfstate bucket. 
+Perform these steps in each account, the very first time, in order to setup the tfstate bucket. 
 
-**IMPORTANT:** This has already been performed for this account, so this is documented here just for reference.
+## Create
 
-Ensure the following environment variables have been set in the `Dockerfile`:
+Provision the bucket:
 ```
-ENV TF_BUCKET="cp-staging-terraform-state"
-ENV TF_BUCKET_REGION="us-west-2"
-ENV TF_DYNAMODB_TABLE="cp-staging-terraform-state-lock"
+make init
 ```
 
-Then run these commands:
-
-1. Comment out the `s3 { ... }` section in `main.tf`
-
-2. Run `init-terraform`
+Follow the instructions at the end. Ensure the environment variables have been set in the `Dockerfile`.
+They look something like this:
+```
+ENV TF_BUCKET="cpco-staging-terraform-state"
+ENV TF_BUCKET_REGION="us-west-2"
+ENV TF_DYNAMODB_TABLE="cpco-staging-terraform-state-lock"
+```
 
-3. Run `terraform apply`
+## Destroy
 
-4. Re-enable `s3 { ... }` section in `main.tf`
+To destroy the state bucket, first make sure all services in the account have already been destroyed. 
 
-5. Re-run `init-terraform`
+Then run:
+```
+make destroy
+```
 
-6. Re-run `terraform apply`, answer `yes` when asked to import state
+**NOTE:** This will only work if the state was previously initialized with `force_destroy=true`. If not, set `force_destroy=true`, rerun `terraform apply`, then run `make destroy`.

aws/tfstate-backend/main.tf

@@ -51,12 +51,19 @@ variable "region" {
   default     = "us-west-2"
 }
 
+variable "force_destroy" {
+  type        = "string"
+  description = "A boolean that indicates the S3 bucket can be destroyed even if it contains objects. These objects are not recoverable."
+  default     = "false"
+}
+
 module "tfstate_backend" {
-  source     = "git::https://github.com/cloudposse/terraform-aws-tfstate-backend.git?ref=tags/0.1.1"
-  namespace  = "${var.namespace}"
-  name       = "${var.name}"
-  stage      = "${var.stage}"
-  attributes = "${var.attributes}"
-  tags       = "${var.tags}"
-  region     = "${var.region}"
+  source        = "git::https://github.com/cloudposse/terraform-aws-tfstate-backend.git?ref=tags/0.1.1"
+  namespace     = "${var.namespace}"
+  name          = "${var.name}"
+  stage         = "${var.stage}"
+  attributes    = "${var.attributes}"
+  tags          = "${var.tags}"
+  region        = "${var.region}"
+  force_destroy = "${var.force_destroy}"
 }

aws/tfstate-backend/scripts/destroy.sh

@@ -0,0 +1,30 @@
+# Start with a clean slate
+rm -rf .terraform terraform.tfstate
+
+# Init terraform with S3 state enabled. Assumes state was previously initialized.
+init-terraform
+
+# Unmount remote bucket (if mounted)
+s3 unmount
+
+# Store the current state so we can destroy resources without catch-22
+terraform state pull > terraform.tfstate
+
+# Delete current state folder to remove all hints of local & remote state
+rm -rf .terraform
+
+# Disable S3 state backend so that we use local state file
+sed -Ei 's/^(\s+backend\s+)/#\1/' main.tf
+
+# Reintialize TF state without backend, using local `terraform.tfstate`
+terraform init
+
+# Destroy terraform state. Note, only buckets that were created with `force_destroy=true` will successfully be destroyed.
+#   https://github.com/hashicorp/terraform/issues/7854#issuecomment-293893541
+terraform destroy -auto-approve
+
+# Re-enable S3 backend
+sed -Ei 's/^#(\s+backend\s+)/\1/' main.tf
+
+# Clean up
+rm -rf .terraform terraform.tfstate

aws/tfstate-backend/install.sh → aws/tfstate-backend/scripts/init.sh

@@ -1,27 +1,41 @@
 #!/usr/bin/env bash
+# This script automates the cold-start process of provisioning the Terraform state backend using terraform
 
 DISABLE_ROLE_ARN=${DISABLE_ROLE_ARN:-0}
 
+# Start from a clean slate
+rm -rf .terraform terraform.tfstate
+
+# Disable S3 backend
 sed -Ei 's/^(\s+backend\s+)/#\1/' main.tf
+
+# Disable Role ARN (necessary for root account on cold-start)
 [ "${DISABLE_ROLE_ARN}" == "0" ] || sed -Ei 's/^(\s+role_arn\s+)/#\1/' main.tf
 
+# Initialize terraform modules and providers
 init-terraform
-echo "yes" | terraform apply
+
+# Provision S3 bucket and dynamodb tables
+terraform apply -auto-approve
 
 export TF_BUCKET=$(terraform output -json | jq -r .tfstate_backend_s3_bucket_id.value)
 export TF_DYNAMODB_TABLE=$(terraform output -json | jq -r .tfstate_backend_dynamodb_table_id.value)
 export TF_BUCKET_REGION=${TF_VAR_region}
 
+# Re-enable S3 backend
 sed -Ei 's/^#(\s+backend\s+)/\1/' main.tf
 
+# Reinitialize terraform to import state to remote backend
 echo "yes" | init-terraform
 
+# Re-enable Role ARN
 [ "${DISABLE_ROLE_ARN}" == "0" ] || sed -Ei 's/^#(\s+role_arn\s+)/\1/' main.tf
 
+# Describe how to use the S3/DynamoDB resources with Geodesic
 echo "Add the following to the Geodesic Module's Dockerfile:"
 echo "#----------------------------------------------"
 echo "ENV TF_BUCKET=\"${TF_BUCKET}\""
 echo "ENV TF_BUCKET_REGION=\"${TF_BUCKET_REGION}\""
 echo "ENV TF_DYNAMODB_TABLE=\"${TF_DYNAMODB_TABLE}\""
 echo "#----------------------------------------------"
-echo "And rebuild the module"
+echo "...and rebuild the module"

aws/tfstate-backend/terraform.tfvars.example

@@ -1,2 +1,3 @@
 namespace="cp"
 stage="staging"
+force_destroy="false"