Make paramiko import optional

Since paramiko does not support FIPS, some deployments
may run without paramiko installed.  Handle this in
ssh_utils.

(This does not handle the paramiko requirement for
drivers that import it directly.)

Change-Id: Id87876543df825f9d84938c615c5976abdebd8f4

cinder/exception.py

@@ -1092,3 +1092,7 @@ class DriverInitiatorDataExists(Duplicate):
         "Driver initiator data for initiator '%(initiator)s' and backend "
         "'%(namespace)s' with key '%(key)s' already exists."
     )
+
+
+class RequirementMissing(CinderException):
+    message = _('Requirement %(req)s is not installed.')

cinder/ssh_utils.py

@@ -24,7 +24,11 @@ from eventlet import pools
 from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import excutils
-import paramiko
+
+try:
+    import paramiko
+except ImportError:
+    paramiko = None
 
 from cinder import exception
 from cinder.i18n import _
@@ -65,6 +69,9 @@ class SSHPool(pools.Pool):
         self.hosts_key_file = None
         self.current_size = 0
 
+        if paramiko is None:
+            raise exception.RequirementMissing(req='paramiko')
+
         # Validate good config setting here.
         # Paramiko handles the case where the file is inaccessible.
         if not CONF.ssh_hosts_key_file:

cinder/tests/unit/test_ssh_utils.py

@@ -405,3 +405,11 @@ class SSHPoolTestCase(test.TestCase):
         sshpool = None
         self.assertEqual(fake_close.mock_calls, close_expect_calls +
                          close_expect_calls)
+
+    @mock.patch('cinder.ssh_utils.paramiko', new=None)
+    def test_missing_paramiko(self):
+        self.assertRaises(exception.RequirementMissing,
+                          ssh_utils.SSHPool,
+                          '192.0.2.1', 22, 10,
+                          'test',
+                          password='hello')