[1372] covered NotImplemented case

src/bin/xfrout/tests/xfrout_test.py.in

@@ -143,6 +143,8 @@ class MockDataSrcClient:
     def get_journal_reader(self, zone_name, begin_serial, end_serial):
         if zone_name == Name('notauth2.example.com'):
             return isc.datasrc.ZoneJournalReader.NO_SUCH_ZONE, None
+        if zone_name == Name('nojournal.example.com'):
+            raise isc.datasrc.NotImplemented('journaling not supported')
         if begin_serial == IXFR_NG_VERSION:
             return isc.datasrc.ZoneJournalReader.NO_SUCH_VERSION, None
         return isc.datasrc.ZoneJournalReader.SUCCESS, self
@@ -710,6 +712,11 @@ class TestXfroutSession(TestXfroutSessionBase):
         self.assertNotEqual(None, self.xfrsess._iterator)
         self.assertEqual(None, self.xfrsess._jnl_reader)
 
+        # The data source doesn't support journaling.  Should fallback to AXFR.
+        self.assertEqual(self.xfrsess._xfrout_setup(
+                self.getmsg(), Name('nojournal.example.com')), Rcode.NOERROR())
+        self.assertNotEqual(None, self.xfrsess._iterator)
+
         # Failure cases
         self.assertEqual(self.xfrsess._xfrout_setup(
                 self.getmsg(), Name('notauth.example.com')), Rcode.NOTAUTH())

src/bin/xfrout/xfrout.py.in

@@ -381,11 +381,18 @@ class XfroutSession():
         rcode, self._soa = self._get_zone_soa(zone_name)
         if rcode != Rcode.NOERROR():
             return rcode
-        code, self._jnl_reader = self._datasrc_client.get_journal_reader(
-            zone_name, get_soa_serial(remote_soa.get_rdata()[0]),
-            get_soa_serial(self._soa.get_rdata()[0]))
+        try:
+            code, self._jnl_reader = self._datasrc_client.get_journal_reader(
+                zone_name, get_soa_serial(remote_soa.get_rdata()[0]),
+                get_soa_serial(self._soa.get_rdata()[0]))
+        except isc.datasrc.NotImplemented as ex:
+            # The underlying data source doesn't support journaling.
+            # Fallback to AXFR-style IXFR.
+            # TBD: log it.
+            return self.__setup_axfr(zone_name)
         if code == ZoneJournalReader.NO_SUCH_VERSION:
             # fallback to AXFR-style IXFR
+            # TBD: log it.
             return self.__setup_axfr(zone_name)
         if code == ZoneJournalReader.NO_SUCH_ZONE:
             # this is quite unexpected as we know zone's SOA exists.