[Container driver] Fix volume group data collection

On different distros, the vgs command may have a
different format. So, lets ask very specific questions
about the total and free size, and use that response.

Change-Id: I36e5e3ba7be562846687c7cc989028371efae2fc
Needed-By: https://review.openstack.org/#/c/604929/
Closes-Bug: #1794402

manila/share/drivers/container/storage_helper.py

@@ -52,9 +52,19 @@ class LVMHelper(driver.ExecuteMixin):
     def get_share_server_pools(self, share_server=None):
         out, err = self._execute('vgs',
                                  self.configuration.container_volume_group,
-                                 '--rows', run_as_root=True)
-        total_size = re.findall("VSize\s[0-9.]+g", out)[0][6:-1]
-        free_size = re.findall("VFree\s[0-9.]+g", out)[0][6:-1]
+                                 '--options', 'vg_size,vg_free',
+                                 '--noheadings',
+                                 '--units', 'g',
+                                 run_as_root=True)
+        if err:
+            msg = _("Unable to gather size of the volume group %(vg)s to be "
+                    "used by the driver. Error: %(err)s")
+            raise exception.ShareBackendException(
+                msg % {'vg': self.configuration.container_volume_group,
+                       'err': err})
+
+        (free_size, total_size) = sorted(re.findall("\d+\.\d+|\d+", out),
+                                         reverse=False)
         return [{
             'pool_name': self.configuration.container_volume_group,
             'total_capacity_gb': float(total_size),

manila/tests/share/drivers/container/test_storage_helper.py

@@ -13,7 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 """Unit tests for the Storage helper module."""
-
+import ddt
 import functools
 import mock
 
@@ -24,6 +24,7 @@ from manila import test
 from manila.tests.share.drivers.container.fakes import fake_share
 
 
+@ddt.ddt
 class LVMHelperTestCase(test.TestCase):
     """Tests ContainerShareDriver"""
 
@@ -46,12 +47,12 @@ class LVMHelperTestCase(test.TestCase):
                           storage_helper.LVMHelper,
                           None)
 
-    def test_get_share_server_pools(self):
-        ret_vgs = "VSize 100g size\nVFree 100g whatever"
+    @ddt.data("62.50g 72.50g", "    72.50g 62.50g\n", "  <62.50g <72.50g\n")
+    def test_get_share_server_pools(self, ret_vgs):
         expected_result = [{'reserved_percentage': 0,
                             'pool_name': 'manila_docker_volumes',
-                            'total_capacity_gb': 100.0,
-                            'free_capacity_gb': 100.0}]
+                            'total_capacity_gb': 72.5,
+                            'free_capacity_gb': 62.5}]
         self.mock_object(self.LVMHelper, "_execute",
                          mock.Mock(return_value=(ret_vgs, 0)))
 

releasenotes/notes/bug-1794402-fix-share-stats-container-driver-b3cb1fa2987ad4b1.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Pool stats collection has been fixed in the container driver to reflect
+    the differences in formatting of information for the underlying volume
+    groups across different operating systems.