Merge pull request #1736 from tseaver/851-1696-pubsub-api_helper_classes

Factor out API helper classes from 'pubsub.Connection'.

Author: tseaver

gcloud/pubsub/client.py

@@ -17,6 +17,9 @@
 
 from gcloud.client import JSONClient
 from gcloud.pubsub.connection import Connection
+from gcloud.pubsub.connection import _PublisherAPI
+from gcloud.pubsub.connection import _SubscriberAPI
+from gcloud.pubsub.connection import _IAMPolicyAPI
 from gcloud.pubsub.subscription import Subscription
 from gcloud.pubsub.topic import Topic
 
@@ -43,6 +46,28 @@ class Client(JSONClient):
     """
 
     _connection_class = Connection
+    _publisher_api = _subscriber_api = _iam_policy_api = None
+
+    @property
+    def publisher_api(self):
+        """Helper for publisher-related API calls."""
+        if self._publisher_api is None:
+            self._publisher_api = _PublisherAPI(self.connection)
+        return self._publisher_api
+
+    @property
+    def subscriber_api(self):
+        """Helper for subscriber-related API calls."""
+        if self._subscriber_api is None:
+            self._subscriber_api = _SubscriberAPI(self.connection)
+        return self._subscriber_api
+
+    @property
+    def iam_policy_api(self):
+        """Helper for IAM policy-related API calls."""
+        if self._iam_policy_api is None:
+            self._iam_policy_api = _IAMPolicyAPI(self.connection)
+        return self._iam_policy_api
 
     def list_topics(self, page_size=None, page_token=None):
         """List topics for the project associated with this client.
@@ -65,8 +90,8 @@ def list_topics(self, page_size=None, page_token=None):
                   more topics can be retrieved with another call (pass that
                   value as ``page_token``).
         """
-        conn = self.connection
-        resources, next_token = conn.list_topics(
+        api = self.publisher_api
+        resources, next_token = api.list_topics(
             self.project, page_size, page_token)
         topics = [Topic.from_api_repr(resource, self)
                   for resource in resources]
@@ -96,8 +121,8 @@ def list_subscriptions(self, page_size=None, page_token=None):
                   more topics can be retrieved with another call (pass that
                   value as ``page_token``).
         """
-        conn = self.connection
-        resources, next_token = conn.list_subscriptions(
+        api = self.subscriber_api
+        resources, next_token = api.list_subscriptions(
             self.project, page_size, page_token)
         topics = {}
         subscriptions = [Subscription.from_api_repr(resource, self,