Fix Scality SOFS support

The "Scaling backup service" patch [1] in Cinder (merged a couple of days
ago) uses os-brick to perform a local attach volume. It revealed that the
support for Scality SOFS in os-brick was broken. (we did have a CI in
Cinder but the os-brick code path was not fully exercised until [1] merged).

This patch addresses this issue. The patch introduces a new class called
`ScalityRemoteFsClient` which inherits from `RemoteFsClient`. We can't
strictly use the `RemoteFsClient` because how to mount Scality FS is
a bit different from other FS.

Note that without this patch, the Scality Cinder driver is broken, more
precisely cinder backup is broken. So I would appreciate if we can merge
that for Mitaka (which needs another minor/micro(?) release of os-brick)

[1] https://review.openstack.org/#/c/262395/

Change-Id: Icfa09b124d252d1d6b07d9cff8c63c7c0d65cc30

os_brick/initiator/connector.py

@@ -1762,9 +1762,9 @@ class RemoteFsConnector(InitiatorConnector):
                  *args, **kwargs):
         kwargs = kwargs or {}
         conn = kwargs.get('conn')
+        mount_type_lower = mount_type.lower()
         if conn:
             mount_point_base = conn.get('mount_point_base')
-            mount_type_lower = mount_type.lower()
             if mount_type_lower in ('nfs', 'glusterfs', 'scality',
                                     'quobyte', 'vzstorage'):
                 kwargs[mount_type_lower + '_mount_point_base'] = (
@@ -1773,9 +1773,14 @@ class RemoteFsConnector(InitiatorConnector):
         else:
             LOG.warning(_LW("Connection details not present."
                             " RemoteFsClient may not initialize properly."))
-        self._remotefsclient = remotefs.RemoteFsClient(mount_type, root_helper,
-                                                       execute=execute,
-                                                       *args, **kwargs)
+
+        if mount_type_lower == 'scality':
+            cls = remotefs.ScalityRemoteFsClient
+        else:
+            cls = remotefs.RemoteFsClient
+        self._remotefsclient = cls(mount_type, root_helper, execute=execute,
+                                   *args, **kwargs)
+
         super(RemoteFsConnector, self).__init__(
             root_helper, driver=driver,
             execute=execute,

os_brick/remotefs/remotefs.py

@@ -40,7 +40,6 @@ class RemoteFsClient(object):
             'cifs': 'smbfs',
             'glusterfs': 'glusterfs',
             'vzstorage': 'vzstorage',
-            'scality': 'scality_sofs',
             'quobyte': 'quobyte'
         }
 
@@ -230,3 +229,36 @@ class RemoteFsClient(object):
         opt = '%s=%s' % (option, value) if value else option
         opts.append(opt)
         return ",".join(opts) if len(opts) > 1 else opts[0]
+
+
+class ScalityRemoteFsClient(RemoteFsClient):
+    def __init__(self, mount_type, root_helper,
+                 execute=None, *args, **kwargs):
+        self._mount_type = mount_type
+        self._mount_base = kwargs.get(
+            'scality_mount_point_base', "").rstrip('/')
+        if not self._mount_base:
+            raise exception.InvalidParameterValue(
+                err=_('scality_mount_point_base required'))
+        self.root_helper = root_helper
+        self.set_execute(execute or putils.execute)
+        self._mount_options = None
+
+    def get_mount_point(self, device_name):
+        return os.path.join(self._mount_base,
+                            device_name,
+                            "00")
+
+    def mount(self, share, flags=None):
+        """Mount the Scality ScaleOut FS.
+
+        The `share` argument is ignored because you can't mount several
+        SOFS at the same type on a single server. But we want to keep the
+        same method signature for class inheritance purpose.
+        """
+        if self._mount_base in self._read_mounts():
+            LOG.info(_LI('Already mounted: %s'), self._mount_base)
+            return
+        self._execute('mkdir', '-p', self._mount_base, check_exit_code=0)
+        super(ScalityRemoteFsClient, self)._do_mount(
+            'sofs', '/etc/sfused.conf', self._mount_base)

os_brick/tests/initiator/test_connector.py

@@ -159,7 +159,7 @@ class ConnectorTestCase(base.TestCase):
         self.assertEqual(obj.__class__.__name__, "RemoteFsConnector")
 
         obj = connector.InitiatorConnector.factory(
-            'scality', None, scality_sofs_mount_point_base='/mnt/test')
+            'scality', None, scality_mount_point_base='/mnt/test')
         self.assertEqual(obj.__class__.__name__, "RemoteFsConnector")
 
         obj = connector.InitiatorConnector.factory('local', None)
@@ -1665,6 +1665,11 @@ class RemoteFsConnectorTestCase(ConnectorTestCase):
             nfs_mount_point_base=self.TEST_BASE,
             nfs_mount_options='vers=3')
 
+    @mock.patch('os_brick.remotefs.remotefs.ScalityRemoteFsClient')
+    def test_init_with_scality(self, mock_scality_remotefs_client):
+        connector.RemoteFsConnector('scality', root_helper='sudo')
+        self.assertEqual(1, mock_scality_remotefs_client.call_count)
+
     def test_get_search_path(self):
         expected = self.TEST_BASE
         actual = self.connector.get_search_path()

os_brick/tests/remotefs/test_remotefs.py

@@ -174,9 +174,6 @@ class RemoteFsClientTestCase(base.TestCase):
     def test_no_mount_point_vzstorage(self):
         self._test_no_mount_point('vzstorage')
 
-    def test_no_mount_point_scality(self):
-        self._test_no_mount_point('scality')
-
     def test_no_mount_point_quobyte(self):
         self._test_no_mount_point('quobyte')
 
@@ -198,3 +195,32 @@ class RemoteFsClientTestCase(base.TestCase):
         remotefs.RemoteFsClient("nfs", root_helper='true',
                                 nfs_mount_point_base='/fake')
         mock_check_nfs_options.assert_called_once_with()
+
+
+class ScalityRemoteFsClientTestCase(base.TestCase):
+
+    def setUp(self):
+        super(ScalityRemoteFsClientTestCase, self).setUp()
+
+    def test_no_mount_point_scality(self):
+        self.assertRaises(exception.InvalidParameterValue,
+                          remotefs.ScalityRemoteFsClient,
+                          'scality', root_helper='true')
+
+    def test_get_mount_point(self):
+        fsclient = remotefs.ScalityRemoteFsClient(
+            'scality', root_helper='true', scality_mount_point_base='/fake')
+        self.assertEqual('/fake/path/00', fsclient.get_mount_point('path'))
+
+    @mock.patch('oslo_concurrency.processutils.execute')
+    @mock.patch('os_brick.remotefs.remotefs.RemoteFsClient._do_mount')
+    def test_mount(self, mock_do_mount, mock_execute):
+        fsclient = remotefs.ScalityRemoteFsClient(
+            'scality', root_helper='true', scality_mount_point_base='/fake')
+        with mock.patch.object(fsclient, '_read_mounts', return_value={}):
+            fsclient.mount('fake')
+
+        mock_execute.assert_called_once_with(
+            'mkdir', '-p', '/fake', check_exit_code=0)
+        mock_do_mount.assert_called_once_with(
+            'sofs', '/etc/sfused.conf', '/fake')