Fix logic for optional dynamodb table (#103)

* Fix dynamodb optional parameter.

Fixed some template logic and locals that didn't work out of the box
with the optional dynamodb table creation.

* Auto Format

* Revert dynamodb_table_name output value

The table name is derived from the resource itself.

* Auto Format

Co-authored-by: cloudpossebot <11232728+cloudpossebot@users.noreply.github.com>

main.tf

@@ -4,7 +4,7 @@ locals {
   bucket_enabled   = local.enabled && var.bucket_enabled
   dynamodb_enabled = local.enabled && var.dynamodb_enabled
 
-  dynamodb_table_name = coalesce(var.dynamodb_table_name, module.dynamodb_table_label.id)
+  dynamodb_table_name = local.dynamodb_enabled ? coalesce(var.dynamodb_table_name, module.dynamodb_table_label.id) : ""
 
   prevent_unencrypted_uploads = local.enabled && var.prevent_unencrypted_uploads && var.enable_server_side_encryption
 
@@ -25,13 +25,13 @@ locals {
     region = data.aws_region.current.name
     bucket = join("", aws_s3_bucket.default.*.id)
 
-    dynamodb_table = element(
+    dynamodb_table = local.dynamodb_enabled ? element(
       coalescelist(
         aws_dynamodb_table.with_server_side_encryption.*.name,
         aws_dynamodb_table.without_server_side_encryption.*.name
       ),
       0
-    )
+    ) : ""
 
     encrypt              = var.enable_server_side_encryption ? "true" : "false"
     role_arn             = var.role_arn

templates/terraform.tf.tpl

@@ -5,7 +5,9 @@ terraform {
     region         = "${region}"
     bucket         = "${bucket}"
     key            = "${terraform_state_file}"
+    %{~ if dynamodb_table != "" ~}
     dynamodb_table = "${dynamodb_table}"
+    %{~ endif ~}
     profile        = "${profile}"
     role_arn       = "${role_arn}"
     encrypt        = "${encrypt}"