use cloud run bindings for cf v2 invoker role, refactor iam handling in cf v2 and cloud run (#1609)

modules/cloud-function-v2/README.md

@@ -4,6 +4,21 @@ Cloud Function management, with support for IAM roles and optional bucket creati
 
 The GCS object used for deployment uses a hash of the bundle zip contents in its name, which ensures change tracking and avoids recreating the function if the GCS object is deleted and needs recreating.
 
+<!-- BEGIN TOC -->
+- [TODO](#todo)
+- [Examples](#examples)
+  - [HTTP trigger](#http-trigger)
+  - [PubSub and non-HTTP triggers](#pubsub-and-non-http-triggers)
+  - [Controlling HTTP access](#controlling-http-access)
+  - [GCS bucket creation](#gcs-bucket-creation)
+  - [Service account management](#service-account-management)
+  - [Custom bundle config](#custom-bundle-config)
+  - [Private Cloud Build Pool](#private-cloud-build-pool)
+  - [Multiple Cloud Functions within project](#multiple-cloud-functions-within-project)
+- [Variables](#variables)
+- [Outputs](#outputs)
+<!-- END TOC -->
+
 ## TODO
 
 - [ ] add support for `source_repository`
@@ -67,7 +82,7 @@ as documented [here](https://cloud.google.com/eventarc/docs/roles-permissions#pu
 
 ### Controlling HTTP access
 
-To allow anonymous access to the function, grant the `roles/cloudfunctions.invoker` role to the special `allUsers` identifier. Use specific identities (service accounts, groups, etc.) instead of `allUsers` to only allow selective access.
+To allow anonymous access to the function, grant the `roles/run.invoker` role to the special `allUsers` identifier. Use specific identities (service accounts, groups, etc.) instead of `allUsers` to only allow selective access. The Cloud Run role needs to be used as explained in the [gcloud documentation](https://cloud.google.com/sdk/gcloud/reference/functions/add-invoker-policy-binding#DESCRIPTION).
 
 ```hcl
 module "cf-http" {
@@ -80,7 +95,7 @@ module "cf-http" {
     output_path = "bundle.zip"
   }
   iam = {
-    "roles/cloudfunctions.invoker" = ["allUsers"]
+    "roles/run.invoker" = ["allUsers"]
   }
 }
 # tftest modules=1 resources=3 inventory=iam.yaml

modules/cloud-function-v2/main.tf

@@ -24,28 +24,17 @@ locals {
       : null
     )
   )
-  _iam_run_invoker_members = concat(
-    lookup(var.iam, "roles/run.invoker", []),
-    var.trigger_config == null ? [] :
-    var.trigger_config.service_account_create ? ["serviceAccount:${local.trigger_service_account_email}"] : []
-  )
-  iam = merge(
-    var.iam,
-    length(local._iam_run_invoker_members) == 0 ? {} :
-    {
-      "roles/run.invoker" : local._iam_run_invoker_members
-    },
-  )
   prefix = var.prefix == null ? "" : "${var.prefix}-"
   service_account_email = (
     var.service_account_create
     ? google_service_account.service_account[0].email
     : var.service_account
   )
-  trigger_service_account_email = (
-    try(var.trigger_config.service_account_create, false)
-    ? google_service_account.trigger_service_account[0].email
-    : try(var.trigger_config.service_account_email, null)
+  trigger_sa_create = (
+    try(var.trigger_config.service_account_create, false) == true
+  )
+  trigger_sa_email = try(
+    google_service_account.trigger_service_account[0].email, null
   )
   vpc_connector = (
     var.vpc_connector == null
@@ -104,7 +93,7 @@ resource "google_cloudfunctions2_function" "function" {
           operator  = event_filter.value.operator
         }
       }
-      service_account_email = local.trigger_service_account_email
+      service_account_email = local.trigger_sa_email
       retry_policy          = var.trigger_config.retry_policy
     }
   }
@@ -154,8 +143,10 @@ resource "google_cloudfunctions2_function" "function" {
   labels = var.labels
 }
 
-resource "google_cloudfunctions2_function_iam_binding" "default" {
-  for_each       = local.iam
+resource "google_cloudfunctions2_function_iam_binding" "binding" {
+  for_each = {
+    for k, v in var.iam : k => v if k != "roles/run.invoker"
+  }
   project        = var.project_id
   location       = google_cloudfunctions2_function.function.location
   cloud_function = google_cloudfunctions2_function.function.name
@@ -163,6 +154,39 @@ resource "google_cloudfunctions2_function_iam_binding" "default" {
   members        = each.value
 }
 
+resource "google_cloud_run_service_iam_binding" "invoker" {
+  # cloud run resources are needed for invoker role to the underlying service
+  count = (
+    lookup(var.iam, "roles/run.invoker", null) != null
+  ) ? 1 : 0
+  project  = var.project_id
+  location = google_cloudfunctions2_function.function.location
+  service  = google_cloudfunctions2_function.function.name
+  role     = "roles/run.invoker"
+  members = distinct(compact(concat(
+    lookup(var.iam, "roles/run.invoker", []),
+    (
+      !local.trigger_sa_create
+      ? []
+      : ["serviceAccount:${local.trigger_sa_email}"]
+    )
+  )))
+}
+
+resource "google_cloud_run_service_iam_member" "invoker" {
+  # if authoritative invoker role is not present and we create trigger sa
+  # use additive binding to grant it the role
+  count = (
+    lookup(var.iam, "roles/run.invoker", null) == null &&
+    local.trigger_sa_create
+  ) ? 1 : 0
+  project  = var.project_id
+  location = google_cloudfunctions2_function.function.location
+  service  = google_cloudfunctions2_function.function.name
+  role     = "roles/run.invoker"
+  member   = "serviceAccount:${local.trigger_sa_email}"
+}
+
 resource "google_storage_bucket" "bucket" {
   count                       = var.bucket_config == null ? 0 : 1
   project                     = var.project_id
@@ -216,9 +240,7 @@ resource "google_service_account" "service_account" {
 }
 
 resource "google_service_account" "trigger_service_account" {
-  count = (
-    try(var.trigger_config.service_account_create, false) == true ? 1 : 0
-  )
+  count        = local.trigger_sa_create ? 1 : 0
   project      = var.project_id
   account_id   = "tf-cf-trigger-${var.name}"
   display_name = "Terraform trigger for Cloud Function ${var.name}."

modules/cloud-function-v2/outputs.tf

@@ -66,14 +66,14 @@ output "trigger_service_account" {
 
 output "trigger_service_account_email" {
   description = "Service account email."
-  value       = local.trigger_service_account_email
+  value       = local.trigger_sa_email
 }
 
 output "trigger_service_account_iam_email" {
   description = "Service account email."
   value = join("", [
     "serviceAccount:",
-    local.trigger_service_account_email == null ? "" : local.trigger_service_account_email
+    local.trigger_sa_email == null ? "" : local.trigger_sa_email
   ])
 }