Catch OSError thrown when hexdump is missing

Change c5bf7b088f introduced
a new requirement via a pre-existing ironic-lib method being
called that utilizes hexdump. Hexdump is not always present
and since we did not explicitly call it out as a new
requirement, we should at least somewhat gracefully handle
the exception.

Change-Id: Id0223ef1417f6e419770ceb56b2a3b80c6118a85
Closes-Bug: #1732470

ironic_python_agent/extensions/standby.py

@@ -154,9 +154,17 @@ def _message_format(msg, image_info, device, partition_uuids):
             result_msg = msg + 'root_uuid={}'
             message = result_msg.format(image_info['id'], device, root_uuid)
     else:
-        root_uuid = disk_utils.get_disk_identifier(device)
-        result_msg = msg + 'root_uuid={}'
-        message = result_msg.format(image_info['id'], device, root_uuid)
+        try:
+            # NOTE(TheJulia): ironic-lib disk_utils.get_disk_identifier
+            # can raise OSError if hexdump is not found.
+            root_uuid = disk_utils.get_disk_identifier(device)
+            result_msg = msg + 'root_uuid={}'
+            message = result_msg.format(image_info['id'], device, root_uuid)
+        except OSError as e:
+            LOG.warning('Failed to call get_disk_identifier: '
+                        'Unable to obtain the root_uuid parameter: '
+                        'The hexdump tool may be missing in IPA: %s', e)
+            message = result_msg.format(image_info['id'], device)
     return message
 
 

ironic_python_agent/tests/unit/extensions/test_standby.py

@@ -887,6 +887,21 @@ class TestStandbyExtension(base.IronicAgentTest):
                         'efi_system_partition_uuid=efi_id')
         self.assertEqual(expected_msg, result_msg)
 
+    @mock.patch('ironic_lib.disk_utils.get_disk_identifier',
+                autospec=True)
+    def test__message_format_whole_disk_missing_oserror(self,
+                                                        ident_mock):
+        ident_mock.side_effect = OSError
+        image_info = _build_fake_image_info()
+        msg = 'image ({}) already present on device {}'
+        device = '/dev/fake'
+        partition_uuids = {}
+        result_msg = standby._message_format(msg, image_info,
+                                             device, partition_uuids)
+        expected_msg = ('image (fake_id) already present on device '
+                        '/dev/fake')
+        self.assertEqual(expected_msg, result_msg)
+
 
 class TestImageDownload(base.IronicAgentTest):