support firestore cloud function triggers (#2480)

* support firestore cloud function triggers

* document firestore trigger specifics

google/resource_cloudfunctions_function.go

@@ -535,6 +535,10 @@ func expandEventTrigger(configured []interface{}, project string) *cloudfunction
 		shape = "projects/%s/buckets/%s"
 	case strings.HasPrefix(eventType, "providers/cloud.pubsub/eventTypes/"):
 		shape = "projects/%s/topics/%s"
+	case strings.HasPrefix(eventType, "providers/cloud.firestore/eventTypes/"):
+		// Firestore doesn't not yet support multiple databases, so "(default)" is assumed.
+		// https://cloud.google.com/functions/docs/calling/cloud-firestore#deploying_your_function
+		shape = "projects/%s/databases/(default)/documents/%s"
 	}
 
 	return &cloudfunctions.EventTrigger{
@@ -550,9 +554,28 @@ func flattenEventTrigger(eventTrigger *cloudfunctions.EventTrigger) []map[string
 		return result
 	}
 
+	resource := ""
+	switch {
+	case strings.HasPrefix(eventTrigger.EventType, "google.storage.object."):
+		resource = GetResourceNameFromSelfLink(eventTrigger.Resource)
+	case strings.HasPrefix(eventTrigger.EventType, "google.pubsub.topic."):
+		resource = GetResourceNameFromSelfLink(eventTrigger.Resource)
+		// Legacy style triggers
+	case strings.HasPrefix(eventTrigger.EventType, "providers/cloud.storage/eventTypes/"):
+		resource = GetResourceNameFromSelfLink(eventTrigger.Resource)
+	case strings.HasPrefix(eventTrigger.EventType, "providers/cloud.pubsub/eventTypes/"):
+		resource = GetResourceNameFromSelfLink(eventTrigger.Resource)
+	case strings.HasPrefix(eventTrigger.EventType, "providers/cloud.firestore/eventTypes/"):
+		// Simply taking the substring after the last "/" is not sufficient for firestore as resources may have slashes.
+		// For the eventTrigger.Resource "projects/my-project/databases/(default)/documents/messages/{messageId}" we extract
+		// the resource "messages/{messageId}" by taking the everything after the 5th "/"
+		parts := strings.SplitN(eventTrigger.Resource, "/", 6)
+		resource = parts[len(parts)-1]
+	}
+
 	result = append(result, map[string]interface{}{
 		"event_type":     eventTrigger.EventType,
-		"resource":       GetResourceNameFromSelfLink(eventTrigger.Resource),
+		"resource":       resource,
 		"failure_policy": flattenFailurePolicy(eventTrigger.FailurePolicy),
 	})
 

google/resource_cloudfunctions_function_test.go

@@ -23,6 +23,7 @@ const testHTTPTriggerPath = "./test-fixtures/cloudfunctions/http_trigger.js"
 const testHTTPTriggerUpdatePath = "./test-fixtures/cloudfunctions/http_trigger_update.js"
 const testPubSubTriggerPath = "./test-fixtures/cloudfunctions/pubsub_trigger.js"
 const testBucketTriggerPath = "./test-fixtures/cloudfunctions/bucket_trigger.js"
+const testFirestoreTriggerPath = "./test-fixtures/cloudfunctions/firestore_trigger.js"
 
 func TestAccCloudFunctionsFunction_basic(t *testing.T) {
 	t.Parallel()
@@ -205,6 +206,34 @@ func TestAccCloudFunctionsFunction_bucket(t *testing.T) {
 	})
 }
 
+func TestAccCloudFunctionsFunction_firestore(t *testing.T) {
+	t.Parallel()
+	funcResourceName := "google_cloudfunctions_function.function"
+	functionName := fmt.Sprintf("tf-test-%s", acctest.RandString(10))
+	bucketName := fmt.Sprintf("tf-test-bucket-%d", acctest.RandInt())
+	zipFilePath, err := createZIPArchiveForIndexJs(testFirestoreTriggerPath)
+	if err != nil {
+		t.Fatal(err.Error())
+	}
+	defer os.Remove(zipFilePath) // clean up
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckCloudFunctionsFunctionDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccCloudFunctionsFunction_firestore(functionName, bucketName, zipFilePath),
+			},
+			{
+				ResourceName:      funcResourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func testAccCheckCloudFunctionsFunctionDestroy(s *terraform.State) error {
 	config := testAccProvider.Meta().(*Config)
 
@@ -508,3 +537,30 @@ resource "google_cloudfunctions_function" "function" {
   }
 }`, bucketName, zipFilePath, functionName)
 }
+
+func testAccCloudFunctionsFunction_firestore(functionName string, bucketName string,
+	zipFilePath string) string {
+	return fmt.Sprintf(`
+resource "google_storage_bucket" "bucket" {
+  name = "%s"
+}
+
+resource "google_storage_bucket_object" "archive" {
+  name   = "index.zip"
+  bucket = "${google_storage_bucket.bucket.name}"
+  source = "%s"
+}
+
+resource "google_cloudfunctions_function" "function" {
+  name                  = "%s"
+  available_memory_mb   = 128
+  source_archive_bucket = "${google_storage_bucket.bucket.name}"
+  source_archive_object = "${google_storage_bucket_object.archive.name}"
+  timeout               = 61
+  entry_point           = "helloFirestore"
+  event_trigger {
+    event_type = "providers/cloud.firestore/eventTypes/document.write"
+    resource   = "messages/{messageId}"
+  }
+}`, bucketName, zipFilePath, functionName)
+}

google/test-fixtures/cloudfunctions/firestore_trigger.js

@@ -0,0 +1,13 @@
+/**
+ * Background Cloud Function to be triggered by Firestore.
+ *
+ * @param {object} event The Cloud Functions event.
+ * @param {function} callback The callback function.
+ */
+exports.helloFirestore = function (event, callback) {
+    const messageId = event.params.messageId;
+
+    console.log(`Received message ${messageId}`);
+
+    callback();
+};

website/docs/r/cloudfunctions_function.html.markdown

@@ -78,9 +78,9 @@ The `event_trigger` block supports:
 
 * `event_type` - (Required) The type of event to observe. For example: `"google.storage.object.finalize"`.
 See the documentation on [calling Cloud Functions](https://cloud.google.com/functions/docs/calling/) for a full reference.
-Only Cloud Storage and Cloud Pub/Sub triggers are supported at this time.
-Legacy Cloud Storage and Cloud Pub/Sub triggers are also supported, such as `"providers/cloud.storage/eventTypes/object.change"`
-and `"providers/cloud.pubsub/eventTypes/topic.publish"`.
+Cloud Storage, Cloud Pub/Sub and Cloud Firestore triggers are supported at this time.
+Legacy triggers are supported, such as `"providers/cloud.storage/eventTypes/object.change"`, 
+`"providers/cloud.pubsub/eventTypes/topic.publish"` and `"providers/cloud.firestore/eventTypes/document.create"`.
 
 * `resource` - (Required) Required. The name of the resource from which to observe events, for example, `"myBucket"`