docs: Create main.tf to support quickstart in Eventarc docset (#784)

* docs: Create main.tf

Per b/355941670

Create new Terraform quickstart for Eventarc

* docs: Update main.tf

For direct Pub/Sub events, you don't need to grant the Eventarc Event Receiver role

---------

Co-authored-by: Jennifer Davis <[email protected]>
Co-authored-by: Katie McLaughlin <[email protected]>

Author: 3 people

eventarc/basic_pubsub/main.tf

@@ -0,0 +1,123 @@
+/**
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+# [START eventarc_basic_pubsub_parent_tag]
+# [START eventarc_basic_pubsub_enableapis]
+# Enable Cloud Run API
+resource "google_project_service" "run" {
+  service            = "run.googleapis.com"
+  disable_on_destroy = false
+}
+
+# Enable Eventarc API
+resource "google_project_service" "eventarc" {
+  service            = "eventarc.googleapis.com"
+  disable_on_destroy = false
+}
+
+# Enable Pub/Sub API
+resource "google_project_service" "pubsub" {
+  service            = "pubsub.googleapis.com"
+  disable_on_destroy = false
+}
+# [END eventarc_basic_pubsub_enableapis]
+
+# [START eventarc_basic_pubsub_iam]
+# Used to retrieve project information later
+data "google_project" "project" {}
+
+# Create a dedicated service account
+resource "google_service_account" "eventarc" {
+  account_id   = "eventarc-trigger-sa"
+  display_name = "Eventarc trigger service account"
+}
+
+# Grant permission to invoke Cloud Run services
+resource "google_project_iam_member" "runinvoker" {
+  project = data.google_project.project.id
+  role    = "roles/run.invoker"
+  member  = "serviceAccount:${google_service_account.eventarc.email}"
+}
+
+# Grant permission to publish messages to a Pub/Sub topic
+resource "google_project_iam_member" "pubsubpublisher" {
+  project = data.google_project.project.id
+  member  = "serviceAccount:${google_service_account.eventarc.email}"
+  role    = "roles/pubsub.publisher"
+}
+# [END eventarc_basic_pubsub_iam]
+
+# [START eventarc_basic_pubsub_deploy_cloud_run]
+# Deploy a Cloud Run service
+resource "google_cloud_run_v2_service" "default" {
+  name     = "hello-events"
+  location = "us-central1"
+
+  deletion_protection = false # set to "true" in production
+
+  template {
+    containers {
+      # This container will log received events
+      image = "us-docker.pkg.dev/cloudrun/container/hello"
+    }
+    service_account = google_service_account.eventarc.email
+  }
+
+  depends_on = [google_project_service.run]
+}
+# [END eventarc_basic_pubsub_deploy_cloud_run]
+
+# [START eventarc_basic_pubsub_topic]
+# Create a Pub/Sub topic
+resource "google_pubsub_topic" "default" {
+  name = "pubsub_topic"
+}
+# [END eventarc_basic_pubsub_topic]
+
+# [START eventarc_basic_pubsub_trigger]
+# Create an Eventarc trigger, routing Pub/Sub events to Cloud Run
+resource "google_eventarc_trigger" "default" {
+  name     = "trigger-pubsub-cloudrun-tf"
+  location = google_cloud_run_v2_service.default.location
+
+  # Capture messages published to a Pub/Sub topic
+  matching_criteria {
+    attribute = "type"
+    value     = "google.cloud.pubsub.topic.v1.messagePublished"
+  }
+
+  # Send events to Cloud Run
+  destination {
+    cloud_run_service {
+      service = google_cloud_run_v2_service.default.name
+      region  = google_cloud_run_v2_service.default.location
+    }
+  }
+
+  transport {
+    pubsub {
+      topic = google_pubsub_topic.default.id
+    }
+  }
+
+  service_account = google_service_account.eventarc.email
+  depends_on = [
+    google_project_service.eventarc,
+    google_project_iam_member.pubsubpublisher
+  ]
+}
+# [END eventarc_basic_pubsub_trigger]
+# [END eventarc_basic_pubsub_parent_tag]