plugins/ceph: Handle Ceph versions prior to Mimic

The command line tool ``ceph-authtool`` grew the ``--mode``
command line argument in the Ceph Mimic release.

We need to support versions prior to that as well.

Change-Id: I163581f3133e2c6033a55f389411b9309a6562d2
Closes-Bug: #1822114

charms_openstack/plugins/classes.py

@@ -142,10 +142,20 @@ class BaseOpenStackCephCharm(object):
                                 self.ceph_key_name))
         keyring_absolute_path = os.path.join(self.ceph_keyring_path,
                                              keyring_name)
-        subprocess.check_call([
+        cmd = [
             'ceph-authtool', keyring_absolute_path,
             '--create-keyring', '--name={}'.format(self.ceph_key_name),
-            '--add-key', interface.key, '--mode', '0600'])
+            '--add-key', interface.key, '--mode', '0600',
+        ]
+        try:
+            subprocess.check_call(cmd)
+        except subprocess.CalledProcessError as cp:
+            if not cp.returncode == 1:
+                raise
+            # the version of ceph-authtool on the system does not have
+            # --mode command line argument
+            subprocess.check_call(cmd[:-2])
+            os.chmod(keyring_absolute_path, 0o600)
         shutil.chown(keyring_absolute_path, user=self.user, group=self.group)
         return keyring_absolute_path
 

unit_tests/charms_openstack/plugins/test_classes.py

@@ -1,5 +1,6 @@
 import mock
 import os
+import subprocess
 
 from unit_tests.charms_openstack.charm.utils import BaseOpenStackCharmTest
 
@@ -89,6 +90,30 @@ class TestOpenStackCephConsumingCharm(BaseOpenStackCharmTest):
             '/etc/ceph/ceph.client.sarepta.keyring',
             user='ceph', group='ceph')
 
+        self.patch_object(cpl.os, 'chmod')
+        self.check_call.side_effect = [
+            subprocess.CalledProcessError(42, [], ''), None]
+        with self.assertRaises(subprocess.CalledProcessError):
+            self.target.configure_ceph_keyring(interface)
+        self.check_call.reset_mock()
+        self.check_call.side_effect = [
+            subprocess.CalledProcessError(1, [], ''), None]
+        self.target.configure_ceph_keyring(interface)
+        self.check_call.assert_has_calls([
+            mock.call([
+                'ceph-authtool',
+                '/etc/ceph/ceph.client.sarepta.keyring',
+                '--create-keyring', '--name=client.sarepta', '--add-key',
+                'KEY', '--mode', '0600']),
+            mock.call([
+                'ceph-authtool',
+                '/etc/ceph/ceph.client.sarepta.keyring',
+                '--create-keyring', '--name=client.sarepta', '--add-key',
+                'KEY']),
+        ])
+        self.chmod.assert_called_with('/etc/ceph/ceph.client.sarepta.keyring',
+                                      0o600)
+
 
 class TestCephCharm(BaseOpenStackCharmTest):