docs: Add a link to Pub/Sub filtering language public documentation to pubsub.proto

google/cloud/pubsub_v1/gapic/subscriber_client.py

@@ -346,7 +346,8 @@ def create_subscription(
 
  If a dict is provided, it must be of the same form as the protobuf
  message :class:`~google.cloud.pubsub_v1.types.ExpirationPolicy`
- filter_ (str): An expression written in the Cloud Pub/Sub filter language. If
+ filter_ (str): An expression written in the Pub/Sub `filter
+ language <https://cloud.google.com/pubsub/docs/filtering>`__. If
  non-empty, then only ``PubsubMessage``\ s whose ``attributes`` field
  matches the filter are delivered on this subscription. If empty, then no
  messages are filtered out.

google/cloud/pubsub_v1/proto/pubsub.proto

@@ -191,7 +191,8 @@ message PubsubMessage {
  bytes data = 1;
 
  // Attributes for this message. If this field is empty, the message must
- // contain non-empty data.
+ // contain non-empty data. This can be used to filter messages on the
+ // subscription.
  map<string, string> attributes = 2;
 
  // ID of this message, assigned by the server when the message is published.
@@ -700,7 +701,8 @@ message Subscription {
  // value for `expiration_policy.ttl` is 1 day.
  ExpirationPolicy expiration_policy = 11;
 
- // An expression written in the Cloud Pub/Sub filter language. If non-empty,
+ // An expression written in the Pub/Sub [filter
+ // language](https://cloud.google.com/pubsub/docs/filtering). If non-empty,
  // then only `PubsubMessage`s whose `attributes` field matches the filter are
  // delivered on this subscription. If empty, then no messages are filtered
  // out.
@@ -1107,6 +1109,28 @@ message StreamingPullRequest {
  // transferred to the new stream. The same client_id should not be used for
  // different client instances.
  string client_id = 6;
+
+ // Flow control settings for the maximum number of outstanding messages. When
+ // there are `max_outstanding_messages` or more currently sent to the
+ // streaming pull client that have not yet been acked or nacked, the server
+ // stops sending more messages. The sending of messages resumes once the
+ // number of outstanding messages is less than this value. If the value is
+ // <= 0, there is no limit to the number of outstanding messages. This
+ // property can only be set on the initial StreamingPullRequest. If it is set
+ // on a subsequent request, the stream will be aborted with status
+ // `INVALID_ARGUMENT`.
+ int64 max_outstanding_messages = 7;
+
+ // Flow control settings for the maximum number of outstanding bytes. When
+ // there are `max_outstanding_bytes` or more worth of messages currently sent
+ // to the streaming pull client that have not yet been acked or nacked, the
+ // server will stop sending more messages. The sending of messages resumes
+ // once the number of outstanding bytes is less than this value. If the value
+ // is <= 0, there is no limit to the number of outstanding bytes. This
+ // property can only be set on the initial StreamingPullRequest. If it is set
+ // on a subsequent request, the stream will be aborted with status
+ // `INVALID_ARGUMENT`.
+ int64 max_outstanding_bytes = 8;
 }
 
 // Response for the `StreamingPull` method. This response is used to stream