If no resource, don't call Resource.to_dict()

This adds a new method base.Manager._get_as_dict() which
checks whether there is a resource first, before calling
Resource.to_dict(). Code was modified to call this new
method, instead of calling Resource.to_dict() directly.

This fixes the AttributeError that occurs if, for example, one
tries to get the list of driver passthru methods of the 'fake'
driver (via 'ironic driver-get-vendor-passthru-methods fake').
There are no methods, and without this change, an AttributeError
exception is raised. With this fix, an empty list is returned.

Change-Id: Ib6b691cd39ede9c5902b4df29023fd974b367a7d
Closes-Bug: #1626806

ironicclient/common/base.py

@@ -83,6 +83,20 @@ class Manager(object):
         except IndexError:
             return None
 
+    def _get_as_dict(self, resource_id, fields=None):
+        """Retrieve a resource as a dictionary
+
+        :param resource_id: Identifier of the resource.
+        :param fields: List of specific fields to be returned.
+        :returns: a dictionary representing the resource; may be empty
+        """
+
+        resource = self._get(resource_id, fields=fields)
+        if resource:
+            return resource.to_dict()
+        else:
+            return {}
+
     def _format_body_data(self, body, response_key):
         if response_key:
             try:

ironicclient/tests/unit/common/test_base.py

@@ -15,6 +15,7 @@
 
 import copy
 
+import mock
 import testtools
 
 from ironicclient.common import base
@@ -121,6 +122,35 @@ class ManagerTestCase(testtools.TestCase):
                                self.manager.create,
                                **INVALID_ATTRIBUTE_TESTABLE_RESOURCE)
 
+    def test__get(self):
+        resource_id = TESTABLE_RESOURCE['uuid']
+        resource = self.manager._get(resource_id)
+        expect = [
+            ('GET', '/v1/testableresources/%s' % resource_id,
+             {}, None),
+        ]
+        self.assertEqual(expect, self.api.calls)
+        self.assertEqual(resource_id, resource.uuid)
+        self.assertEqual(TESTABLE_RESOURCE['attribute1'], resource.attribute1)
+
+    def test__get_as_dict(self):
+        resource_id = TESTABLE_RESOURCE['uuid']
+        resource = self.manager._get_as_dict(resource_id)
+        expect = [
+            ('GET', '/v1/testableresources/%s' % resource_id,
+             {}, None),
+        ]
+        self.assertEqual(expect, self.api.calls)
+        self.assertEqual(TESTABLE_RESOURCE, resource)
+
+    @mock.patch.object(base.Manager, '_get', autospec=True)
+    def test__get_as_dict_empty(self, mock_get):
+        mock_get.return_value = None
+        resource_id = TESTABLE_RESOURCE['uuid']
+        resource = self.manager._get_as_dict(resource_id)
+        mock_get.assert_called_once_with(mock.ANY, resource_id, fields=None)
+        self.assertEqual({}, resource)
+
     def test_get(self):
         resource = self.manager.get(TESTABLE_RESOURCE['uuid'])
         expect = [

ironicclient/v1/driver.py

@@ -41,7 +41,7 @@ class DriverManager(base.Manager):
         return self._delete(resource_id=driver_name)
 
     def properties(self, driver_name):
-        return self._get(resource_id='%s/properties' % driver_name).to_dict()
+        return self._get_as_dict('%s/properties' % driver_name)
 
     def raid_logical_disk_properties(self, driver_name):
         """Returns the RAID logical disk properties for the driver.
@@ -92,5 +92,4 @@ class DriverManager(base.Manager):
                 _('Unknown HTTP method: %s') % http_method)
 
     def get_vendor_passthru_methods(self, driver_name):
-        path = "%s/vendor_passthru/methods" % driver_name
-        return self.get(path).to_dict()
+        return self._get_as_dict("%s/vendor_passthru/methods" % driver_name)

ironicclient/v1/node.py

@@ -334,10 +334,7 @@ class NodeManager(base.CreateManager):
 
     def get_console(self, node_uuid):
         path = "%s/states/console" % node_uuid
-        info = self.get(path)
-        if not info:
-            return {}
-        return info.to_dict()
+        return self._get_as_dict(path)
 
     def set_console_mode(self, node_uuid, enabled):
         """Set the console mode for the node.
@@ -358,15 +355,15 @@ class NodeManager(base.CreateManager):
 
     def get_boot_device(self, node_uuid):
         path = "%s/management/boot_device" % node_uuid
-        return self.get(path).to_dict()
+        return self._get_as_dict(path)
 
     def get_supported_boot_devices(self, node_uuid):
         path = "%s/management/boot_device/supported" % node_uuid
-        return self.get(path).to_dict()
+        return self._get_as_dict(path)
 
     def get_vendor_passthru_methods(self, node_ident):
         path = "%s/vendor_passthru/methods" % node_ident
-        return self.get(path).to_dict()
+        return self._get_as_dict(path)
 
     def wait_for_provision_state(self, node_ident, expected_state,
                                  timeout=0,

releasenotes/notes/no-resource-attributeerror-d0cb327abab7dcc0.yaml

@@ -0,0 +1,8 @@
+---
+fixes:
+  - For node resources that had no boot devices, no supported boot devices, or
+    no passthru methods (and driver resources with no properties or no passthru
+    methods), issuing a request to get that information (for example,
+    'ironic driver-get-vendor-passthru-methods fake') would result in the
+    error "'NoneType' has no attribute 'to_dict'". This is fixed; an empty
+    list is now returned.