CP-52852: add handler for xmlrpc ProtocolError

It is possible that a XenAPI call to xapi will result in an xmlrpc
ProtocolError being returned, typically a 500 Internal Error. As it is
not practical to wrap all the calls to xapi via the xenapi session in
a specific exception handler add one into the outer run method to
ensure that it is converted to an error code and not an unknown error.

Signed-off-by: Mark Syms <mark.syms@cloud.com>

drivers/SRCommand.py

@@ -17,11 +17,13 @@
 #
 # SRCommand: parse SR command-line objects
 #
+import traceback
 
 import XenAPI # pylint: disable=import-error
 import sys
 import xs_errors
 import xmlrpc.client
+from xmlrpc.client import ProtocolError
 import SR
 import util
 import blktap2
@@ -390,6 +392,14 @@ def run(driver, driver_info):
         else:
             print(ret)
 
+    except ProtocolError:
+        # xs_errors.XenError.__new__ returns a different class
+        # pylint: disable-msg=E1101
+        exception_trace = traceback.format_exc()
+        util.SMlog(f'XenAPI Protocol error {exception_trace}')
+        print(xs_errors.XenError(
+            'APIProtocolError',
+            opterr=exception_trace).toxml())
     except (Exception, xs_errors.SRException) as e:
         try:
             util.logException(driver_info['name'])

drivers/XE_SR_ERRORCODES.xml

@@ -534,6 +534,11 @@
                 <description>A Failure occurred accessing an API object</description>
                 <value>153</value>
         </code>
+        <code>
+                <name>APIProtocolError</name>
+                <description>A protocol error was received when accessing the API</description>
+                <value>154</value>
+        </code>
 
         <!-- Netapp Specific Error codes -->
         <code>

tests/test_SRCommand.py

@@ -1,6 +1,9 @@
 import unittest
 import unittest.mock as mock
+import uuid
+import xmlrpc.client
 
+import SR
 import SRCommand
 
 
@@ -123,6 +126,39 @@ def test_run_wrapped_if_not_SRException(
 
         SRCommand.run(mock_driver, DRIVER_INFO)
 
+    @mock.patch("sys.exit", autospec=True)
+    @mock.patch('util.logException', autospec=True)
+    @mock.patch('SRCommand.SRCommand', autospec=True)
+    def test_run_reports_protocol_error(
+            self,
+            mock_sr_command,
+            mock_logException,
+            mock_exit):
+
+        """
+        If XenAPI raises a protocol error convert to error code
+        """
+        from DummySR import DRIVER_INFO
+
+        def raise_error(sr):
+            raise xmlrpc.client.ProtocolError(
+                'XapiUrl', 500,
+                'Internal Error', {})
+
+        # Create function to raise exception in SRCommand.run()
+        mock_cmd = mock.MagicMock()
+        mock_cmd.run.side_effect = raise_error
+        mock_cmd.sr_uuid = str(uuid.uuid4())
+        mock_sr_command.return_value = mock_cmd
+
+        mock_driver = mock.MagicMock(autospec=SR.SR)
+
+        with mock.patch('builtins.print') as mock_print:
+            SRCommand.run(mock_driver, DRIVER_INFO)
+
+        self.assertIn('<value><int>154</int></value>',
+                      mock_print.call_args[0][0])
+
     @mock.patch("os.fsencode",
                 new=lambda s: s.encode("ascii", "surrogateescape"))
     @mock.patch("os.fsdecode",