Add new field filter to pubsub.

products/pubsub/api.yaml

@@ -244,6 +244,15 @@ objects:
               If ttl is not set, the associated resource never expires.
               A duration in seconds with up to nine fractional digits, terminated by 's'.
               Example - "3.5s".
+      - !ruby/object:Api::Type::String
+        name: 'filter'
+        required: false
+        description: |
+          The subscription only delivers the messages that match the filter. 
+          Pub/Sub automatically acknowledges the messages that don't match the filter. You can filter messages
+          by their attributes. The maximum length of a filter is 256 bytes. After creating the subscription, 
+          you can't modify the filter.
+        input: true
       - !ruby/object:Api::Type::NestedObject
         name: 'deadLetterPolicy'
         send_empty_value: true

third_party/terraform/tests/resource_pubsub_subscription_test.go

@@ -219,8 +219,9 @@ resource "google_pubsub_topic" "foo" {
 }
 
 resource "google_pubsub_subscription" "foo" {
-  name  = "%s"
-  topic = google_pubsub_topic.foo.id
+  name   = "%s"
+  topic  = google_pubsub_topic.foo.id
+  filter = "attributes.foo = \"bar\""
   labels = {
     foo = "%s"
   }