Handle no baremetal_nodes in process_node_filter

- Added a try when getting baremetal_nodes from site_design.
   If baremetal_nodes isn't there it will return an empty set.

Change-Id: I413892274d938ffd23102c73a569b83a59025206

drydock_provisioner/orchestrator/orchestrator.py

@@ -382,7 +382,15 @@ class Orchestrator(object):
             ba.target_nodes = [x.get_id() for x in target_nodes]
 
     def process_node_filter(self, node_filter, site_design):
-        target_nodes = site_design.baremetal_nodes
+        try:
+            target_nodes = site_design.baremetal_nodes
+            if target_nodes is None:
+                raise AttributeError()
+        except AttributeError:
+            self.logger.debug(
+                "Invalid site design, no baremetal nodes in site_design."
+            )
+            return []
 
         if node_filter is None:
             return target_nodes

tests/unit/test_orch_node_filter.py

@@ -62,3 +62,17 @@ class TestClass(object):
         node_list = deckhand_orchestrator.process_node_filter(nfs, design_data)
 
         assert len(node_list) == 1
+
+    def test_no_baremetal_nodes(self, input_files, setup, deckhand_orchestrator,
+                                deckhand_ingester):
+        input_file = input_files.join("deckhand_fullsite_no_nodes.yaml")
+
+        design_state = DrydockState()
+        design_ref = "file://%s" % str(input_file)
+
+        design_status, design_data = deckhand_ingester.ingest_data(
+            design_state=design_state, design_ref=design_ref)
+
+        node_list = deckhand_orchestrator.process_node_filter(None, design_data)
+
+        assert node_list == []