Backend service support for internet NEG backend (#3782) (#66)

* Add ability to set global network endpoint group as backend for backend service. Make health_checks optional

* PR fixes

* Add encoder to remove max_utilization when neg backend

* Check for global NEG in group to remove max_utilization

* Add another nil check

* Spacing

* Docs fix

Signed-off-by: Modular Magician <[email protected]>

backend_service_network_endpoint/backing_file.tf

@@ -0,0 +1,15 @@
+# This file has some scaffolding to make sure that names are unique and that
+# a region and zone are selected when you try to create your Terraform resources.
+
+locals {
+  name_suffix = "${random_pet.suffix.id}"
+}
+
+resource "random_pet" "suffix" {
+  length = 2
+}
+
+provider "google" {
+  region = "us-central1"
+  zone   = "us-central1-c"
+}

backend_service_network_endpoint/main.tf

@@ -0,0 +1,24 @@
+resource "google_compute_global_network_endpoint_group" "external_proxy" {
+  name                  = "network-endpoint-${local.name_suffix}"
+  network_endpoint_type = "INTERNET_FQDN_PORT"
+  default_port          = "443"
+}
+
+resource "google_compute_global_network_endpoint" "proxy" {
+  global_network_endpoint_group = google_compute_global_network_endpoint_group.external_proxy.id
+  fqdn                          = "test.example.com"
+  port                          = google_compute_global_network_endpoint_group.external_proxy.default_port
+}
+
+resource "google_compute_backend_service" "default" {
+  name                            = "backend-service-${local.name_suffix}"
+  enable_cdn                      = true
+  timeout_sec                     = 10
+  connection_draining_timeout_sec = 10
+
+  custom_request_headers          = ["host: ${google_compute_global_network_endpoint.proxy.fqdn}"]
+
+  backend {
+    group = google_compute_global_network_endpoint_group.external_proxy.id
+  }
+}

backend_service_network_endpoint/motd

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+===
+
+These examples use real resources that will be billed to the
+Google Cloud Platform project you use - so make sure that you
+run "terraform destroy" before quitting!
+
+===

backend_service_network_endpoint/tutorial.md

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+# Backend Service Network Endpoint - Terraform
+
+## Setup
+
+<walkthrough-author name="[email protected]" analyticsId="UA-125550242-1" tutorialName="backend_service_network_endpoint" repositoryUrl="https://github.com/terraform-google-modules/docs-examples"></walkthrough-author>
+
+Welcome to Terraform in Google Cloud Shell! We need you to let us know what project you'd like to use with Terraform.
+
+<walkthrough-project-billing-setup></walkthrough-project-billing-setup>
+
+Terraform provisions real GCP resources, so anything you create in this session will be billed against this project.
+
+## Terraforming!
+
+Let's use {{project-id}} with Terraform! Click the Cloud Shell icon below to copy the command
+to your shell, and then run it from the shell by pressing Enter/Return. Terraform will pick up
+the project name from the environment variable.
+
+```bash
+export GOOGLE_CLOUD_PROJECT={{project-id}}
+```
+
+After that, let's get Terraform started. Run the following to pull in the providers.
+
+```bash
+terraform init
+```
+
+With the providers downloaded and a project set, you're ready to use Terraform. Go ahead!
+
+```bash
+terraform apply
+```
+
+Terraform will show you what it plans to do, and prompt you to accept. Type "yes" to accept the plan.
+
+```bash
+yes
+```
+
+
+## Post-Apply
+
+### Editing your config
+
+Now you've provisioned your resources in GCP! If you run a "plan", you should see no changes needed.
+
+```bash
+terraform plan
+```
+
+So let's make a change! Try editing a number, or appending a value to the name in the editor. Then,
+run a 'plan' again.
+
+```bash
+terraform plan
+```
+
+Afterwards you can run an apply, which implicitly does a plan and shows you the intended changes
+at the 'yes' prompt.
+
+```bash
+terraform apply
+```
+
+```bash
+yes
+```
+
+## Cleanup
+
+Run the following to remove the resources Terraform provisioned:
+
+```bash
+terraform destroy
+```
+```bash
+yes
+```