Unity: skip hlu0 for snap host access (#314)

Modify hlu to non-zero after attaching the snap to the host.

storops/connection/client.py

@@ -23,6 +23,7 @@
 
 import requests
 import six
+from requests.exceptions import ConnectTimeout
 from requests.exceptions import RequestException
 from retryz import retry
 
@@ -124,7 +125,7 @@ def _cs_request(self, url, method, **kwargs):
                 self.base_url + url,
                 method,
                 **kwargs)
-        except requests.ConnectTimeout as ex:
+        except ConnectTimeout as ex:
             raise StoropsConnectTimeoutError(message=str(ex))
 
     def _get_limit(self):

storops/unity/resource/host.py

@@ -245,7 +245,8 @@ def _attach_with_retry(self, lun_or_snap, skip_hlu_0):
         # From 4.4.0 (Osprey), it supported to pass in hlu when attaching LUN,
         # but not when attaching snap.
         from storops.unity.resource.lun import UnityLun as _UnityLun
-        if skip_hlu_0 and isinstance(lun_or_snap, _UnityLun):
+        is_lun = isinstance(lun_or_snap, _UnityLun)
+        if skip_hlu_0 and is_lun:
             candidate_hlu = self._random_hlu_number()
             lun_or_snap.attach_to(self, hlu=candidate_hlu)
             self.update()
@@ -254,6 +255,13 @@ def _attach_with_retry(self, lun_or_snap, skip_hlu_0):
             lun_or_snap.attach_to(self)
             self.update()
             host_lun = self.get_host_lun(lun_or_snap)
+
+            # Use the old way to modify the hlu after attaching snap if we need
+            # to skip hlu0 for a snapshot.
+            if (not is_lun) and skip_hlu_0 and host_lun.hlu == 0:
+                candidate_hlu = self._random_hlu_number()
+                self._modify_hlu(host_lun, candidate_hlu)
+                return candidate_hlu
             return host_lun.hlu
 
     def attach(self, lun_or_snap, skip_hlu_0=False):

storops_test/unity/resource/test_host.py

@@ -418,7 +418,7 @@ def test_attach_with_retry_skip_hlu_0(self):
             assert_that(hlu, equal_to(12781))
 
     @patch_rest
-    def test_attach_with_retry_member_snap_skip_hlu_0(self):
+    def test_attach_with_retry_snap_skip_hlu_0(self):
         host = UnityHost(cli=t_rest(), _id='Host_27')
         snap = UnitySnap(_id='38654705831', cli=t_rest())
         with mock.patch('storops.unity.resource.host.UnityHost.'
@@ -427,6 +427,38 @@ def test_attach_with_retry_member_snap_skip_hlu_0(self):
             assert_that(hlu, is_not(equal_to(0)))
             assert_that(hlu, equal_to(12781))
 
+    @patch_rest
+    def test_attach_with_retry_snap_not_skip_hlu_0(self):
+        host = UnityHost(cli=t_rest(), _id='Host_27')
+        snap = UnitySnap(_id='38654705831', cli=t_rest())
+        with mock.patch('storops.unity.resource.host.UnityHost.'
+                        '_random_hlu_number', new=lambda _: 12781):
+            hlu = host._attach_with_retry(snap, False)
+            assert_that(hlu, equal_to(0))
+
+    @patch_rest
+    def test_attach_with_retry_snap_skip_hlu_0_5_0_0(self):
+        host = UnityHost(cli=t_rest(), _id='Host_27')
+        snap = UnitySnap(_id='38654705831', cli=t_rest(version='5.0.0'))
+        with mock.patch('storops.unity.resource.host.UnityHost.'
+                        '_random_hlu_number', new=lambda _: 12782):
+            with mock.patch('storops.unity.resource.host.UnityHost.'
+                            '_modify_hlu') as mock_modify_hlu:
+                hlu = host._attach_with_retry(snap, True)
+                host_lun = host.get_host_lun(snap)
+                mock_modify_hlu.assert_called_with(host_lun, 12782)
+                assert_that(hlu, equal_to(12782))
+
+    @patch_rest
+    def test_attach_with_retry_snap_not_skip_hlu_0_5_0_0(self):
+        host = UnityHost(cli=t_rest(), _id='Host_27')
+        snap = UnitySnap(_id='38654705831', cli=t_rest(version='5.0.0'))
+        with mock.patch('storops.unity.resource.host.UnityHost.'
+                        '_modify_hlu') as mock_modify_hlu:
+            hlu = host._attach_with_retry(snap, False)
+            assert_that(mock_modify_hlu.called, equal_to(False))
+            assert_that(hlu, equal_to(0))
+
     @patch_rest
     def test_attach_with_retry_no_skip_hlu_0(self):
         host = UnityHost(cli=t_rest(), _id='Host_23')