Fix Python 3 issues in backup

* Replace (int, long) with six.integer_types: the "long" type has been
  removed in Python 3
* Replace str.encode("bas64") with base64.encodestring(str), base64
  text codec has been removed in Python 3. Same change for decode
  (base64.decodestring)
* On Python 3, encode JSON to UTF-8
* tox.ini: add the following tests to Python 3

  - cinder.tests.unit.test_backup
  - cinder.tests.unit.test_backup_driver_base

Blueprint cinder-python3
Change-Id: I86e04f8fbe9a3ce8849fd141dc3ee914e73c8796

cinder/backup/driver.py

@@ -16,6 +16,7 @@
 """Base class for all backup drivers."""
 
 import abc
+import base64
 
 from oslo_config import cfg
 from oslo_log import log as logging
@@ -355,7 +356,9 @@ class BackupDriver(base.Base):
         :returns backup_url - a string describing the backup record
         """
         retval = jsonutils.dumps(backup)
-        return retval.encode("base64")
+        if six.PY3:
+            retval = retval.encode('utf-8')
+        return base64.encodestring(retval)
 
     def import_record(self, backup_url):
         """Import and verify backup record.
@@ -367,7 +370,7 @@ class BackupDriver(base.Base):
         :param backup_url: driver specific backup record string
         :returns dictionary object with database updates
         """
-        return jsonutils.loads(backup_url.decode("base64"))
+        return jsonutils.loads(base64.decodestring(backup_url))
 
 
 @six.add_metaclass(abc.ABCMeta)

cinder/quota.py

@@ -347,7 +347,7 @@ class DbQuotaDriver(object):
         # Set up the reservation expiration
         if expire is None:
             expire = CONF.reservation_expire
-        if isinstance(expire, (int, long)):
+        if isinstance(expire, six.integer_types):
             expire = datetime.timedelta(seconds=expire)
         if isinstance(expire, datetime.timedelta):
             expire = timeutils.utcnow() + expire

cinder/tests/unit/test_backup_driver_base.py

@@ -14,6 +14,7 @@
 #    under the License.
 """ Tests for the backup service base driver. """
 
+import base64
 import uuid
 
 import mock
@@ -74,7 +75,7 @@ class BackupBaseDriverTestCase(test.TestCase):
 
     def test_export_record(self):
         export_string = self.driver.export_record(self.backup)
-        export_dict = jsonutils.loads(export_string.decode("base64"))
+        export_dict = jsonutils.loads(base64.decodestring(export_string))
         # Make sure we don't lose data when converting to string
         for key in _backup_db_fields:
             self.assertTrue(key in export_dict)

tox.ini

@@ -30,6 +30,8 @@ downloadcache = ~/cache/pip
 commands =
   python -m testtools.run \
     cinder.tests.unit.test_api_urlmap \
+    cinder.tests.unit.test_backup \
+    cinder.tests.unit.test_backup_driver_base \
     cinder.tests.unit.test_block_device \
     cinder.tests.unit.test_cloudbyte \
     cinder.tests.unit.test_conf \