swarming: refactor cipd input

appengine/swarming/handlers_endpoints.py

Index: appengine/swarming/handlers_endpoints.py
diff --git a/appengine/swarming/handlers_endpoints.py b/appengine/swarming/handlers_endpoints.py
index 394bc408ecafa278c9c6a3213c7e8ab222bf4dd8..24c1724a34ca085a2232892d6b47d8f57d68c331 100644
--- a/appengine/swarming/handlers_endpoints.py
+++ b/appengine/swarming/handlers_endpoints.py
@@ -77,6 +77,24 @@ def get_result_entity(task_id):
   return get_or_raise(key)
 
 
+def apply_property_defaults(properties):
+  """Fills task properties with default values read from server settings."""
+  cfg = config.settings()
+  if not cfg:
+    return
+
+  if cfg.isolate.default_server and cfg.isolate.default_namespace:
+    properties.inputs_ref = properties.inputs_ref or swarming_rpcs.FilesRef()
+    properties.inputs_ref.isolatedserver = (
+        properties.inputs_ref.isolatedserver or cfg.isolate.default_server)
+    properties.inputs_ref.namespace = (
+        properties.inputs_ref.namespace or cfg.isolate.default_namespace)
+
+  cipd_input = properties.cipd_input
+  if cipd_input and not cipd_input.settings and cfg.HasField('cipd'):
+    cipd_input.settings = cfg.cipd.SerializeToString()
+
+
 ### API
 
 
@@ -271,17 +289,7 @@ class SwarmingTasksService(remote.Service):
     if request.properties is None:
       raise endpoints.BadRequestException('properties are required')
 
-    # Apply isolate defaults.
-    cfg = config.settings()
-    if cfg.isolate.default_server and cfg.isolate.default_namespace:
-      request.properties.inputs_ref = (
-          request.properties.inputs_ref or swarming_rpcs.FilesRef())
-      request.properties.inputs_ref.isolatedserver = (
-          request.properties.inputs_ref.isolatedserver or
-          cfg.isolate.default_server)
-      request.properties.inputs_ref.namespace = (
-          request.properties.inputs_ref.namespace or
-          cfg.isolate.default_namespace)
+    apply_property_defaults(request.properties)
 
     try:
       request = message_conversion.new_task_request_from_rpc(