feat: Support page token in API Registry

API registry uses a nextPageToken for pagination, so we should loop through all the pages by sending the received nextPageToken to subsequent requests until no token is returned. The first page contains 1P MCP servers, and later pages contain 3P customer servers.

Co-authored-by: Kathy Wu <wukathy@google.com>
PiperOrigin-RevId: 853880449

tests/unittests/tools/test_api_registry.py

@@ -91,6 +91,7 @@ class TestApiRegistry(unittest.IsolatedAsyncioTestCase):
             "Authorization": "Bearer mock_token",
             "Content-Type": "application/json",
         },
+        params={},
     )
 
   @patch("httpx.Client", autospec=True)
@@ -119,6 +120,71 @@ class TestApiRegistry(unittest.IsolatedAsyncioTestCase):
             "Content-Type": "application/json",
             "x-goog-user-project": "quota-project",
         },
+        params={},
+    )
+
+  @patch("httpx.Client", autospec=True)
+  def test_init_with_pagination_success(self, MockHttpClient):
+    mock_response1 = create_autospec(httpx.Response, instance=True)
+    mock_response1.json.return_value = {
+        "mcpServers": [
+            {
+                "name": "test-mcp-server-1",
+                "urls": ["mcp.server1.com"],
+            },
+            {
+                "name": "test-mcp-server-2",
+                "urls": ["mcp.server2.com"],
+            },
+        ],
+        "nextPageToken": "next_page_token",
+    }
+    mock_response2 = create_autospec(httpx.Response, instance=True)
+    mock_response2.json.return_value = {
+        "mcpServers": [
+            {
+                "name": "test-mcp-server-no-url",
+            },
+            {
+                "name": "test-mcp-server-http",
+                "urls": ["http://mcp.server_http.com"],
+            },
+            {
+                "name": "test-mcp-server-https",
+                "urls": ["https://mcp.server_https.com"],
+            },
+        ]
+    }
+    mock_client_instance = MockHttpClient.return_value
+    mock_client_instance.__enter__.return_value = mock_client_instance
+    mock_client_instance.get.side_effect = [mock_response1, mock_response2]
+
+    api_registry = ApiRegistry(
+        api_registry_project_id=self.project_id, location=self.location
+    )
+
+    self.assertEqual(len(api_registry._mcp_servers), 5)
+    self.assertIn("test-mcp-server-1", api_registry._mcp_servers)
+    self.assertIn("test-mcp-server-2", api_registry._mcp_servers)
+    self.assertIn("test-mcp-server-no-url", api_registry._mcp_servers)
+    self.assertIn("test-mcp-server-http", api_registry._mcp_servers)
+    self.assertIn("test-mcp-server-https", api_registry._mcp_servers)
+    self.assertEqual(mock_client_instance.get.call_count, 2)
+    mock_client_instance.get.assert_any_call(
+        f"https://cloudapiregistry.googleapis.com/v1beta/projects/{self.project_id}/locations/{self.location}/mcpServers",
+        headers={
+            "Authorization": "Bearer mock_token",
+            "Content-Type": "application/json",
+        },
+        params={},
+    )
+    mock_client_instance.get.assert_called_with(
+        f"https://cloudapiregistry.googleapis.com/v1beta/projects/{self.project_id}/locations/{self.location}/mcpServers",
+        headers={
+            "Authorization": "Bearer mock_token",
+            "Content-Type": "application/json",
+        },
+        params={"pageToken": "next_page_token"},
     )
 
   @patch("httpx.Client", autospec=True)