Add support for GCP project as env vars (#43)

Signed-off-by: Jim Enright <jenright@cloudera.com>

README.md

@@ -69,16 +69,18 @@ export ARM_SUBSCRIPTION_ID="<sp_subscription_id>"
 
 * The Google Cloud IAM roles listed below are required by the provisioning account to create the GCP pre-requisite resources.
 
-| IAM Role                  | 
-| ------------------------- | 
-| Compute Network Admin     | 
-| Compute Security Admin    | 
-| Role Administrator        | 
-| Security Admin            | 
-| Service Account Admin     | 
-| Service Account Key Admin | 
-| Storage Admin             | 
-| Viewer                    | 
+| IAM Role                  |
+| ------------------------- |
+| Compute Network Admin     |
+| Compute Security Admin    |
+| Role Administrator        |
+| Security Admin            |
+| Service Account Admin     |
+| Service Account Key Admin |
+| Storage Admin             |
+| Viewer                    |
+
+* The Google project Id can be specified via the `gcp_project` input variable, the `GOOGLE_PROJECT` environment variable or the default project set via the Cloud SDK. This is described in the [Google Provider Default Values Configuration](https://registry.terraform.io/providers/hashicorp/google/latest/docs/guides/provider_reference#provider-default-values-configuration) documentation.
 
 ### Input file configuration
 

gcp/main.tf

@@ -66,7 +66,7 @@ module "cdp_deploy" {
 
   env_prefix          = var.env_prefix
   infra_type          = "gcp"
-  gcp_project_id      = var.gcp_project
+  gcp_project_id      = data.google_project.project.project_id
   region              = var.gcp_region
   public_key_text     = local.public_key_text
   deployment_template = var.deployment_template
@@ -105,6 +105,9 @@ module "cdp_deploy" {
   ]
 }
 
+# Use the Google Cloud Provider to retrieve GCP project details
+data "google_project" "project" {}
+
 # ------- Create SSH Keypair if input public_key_text variable is not specified
 locals {
   # flag to determine if keypair should be created

gcp/variables.tf

@@ -20,7 +20,9 @@ variable "env_prefix" {
 
 variable "gcp_project" {
   type        = string
-  description = "Region which Cloud resources will be created"
+  description = "Region which Cloud resources will be created. Can also be set via gcloud project default or environment variable."
+
+  default = null
 }
 
 variable "gcp_region" {