XenAPI: Add versioning for plugins

Because the plugins live on a host seperate to Nova we need an interface
to test whether they are the expected version.  We can't use pip or other
requirement systems as they are cross-machine.

Closes bug 1226622

Change-Id: I58ab669061f51bd87071e2cf0d93d33021001309

nova/tests/virt/xenapi/stubs.py

@@ -240,6 +240,9 @@ class FakeSessionForFirewallTests(FakeSessionForVMTests):
                         output = '\n'.join(lines)
                 ret_str = fake.as_json(out=output, err='')
             return ret_str
+        else:
+            return (super(FakeSessionForVMTests, self).
+                    host_call_plugin(_1, _2, plugin, method, args))
 
 
 def stub_out_vm_methods(stubs):

nova/tests/virt/xenapi/test_xenapi.py

@@ -3957,6 +3957,78 @@ class XenAPISessionTestCase(test.NoDBTestCase):
             session._get_product_version_and_brand()
         )
 
+    def test_verify_plugin_version_same(self):
+        session = self._get_mock_xapisession({})
+
+        session.PLUGIN_REQUIRED_VERSION = '2.4'
+
+        self.mox.StubOutWithMock(session, 'call_plugin_serialized')
+        session.call_plugin_serialized('nova_plugin_version', 'get_version',
+                            ).AndReturn("2.4")
+
+        self.mox.ReplayAll()
+        session._verify_plugin_version()
+
+    def test_verify_plugin_version_compatible(self):
+        session = self._get_mock_xapisession({})
+        session.XenAPI = xenapi_fake.FakeXenAPI()
+
+        session.PLUGIN_REQUIRED_VERSION = '2.4'
+
+        self.mox.StubOutWithMock(session, 'call_plugin_serialized')
+        session.call_plugin_serialized('nova_plugin_version', 'get_version',
+                            ).AndReturn("2.5")
+
+        self.mox.ReplayAll()
+        session._verify_plugin_version()
+
+    def test_verify_plugin_version_bad_maj(self):
+        session = self._get_mock_xapisession({})
+        session.XenAPI = xenapi_fake.FakeXenAPI()
+
+        session.PLUGIN_REQUIRED_VERSION = '2.4'
+
+        self.mox.StubOutWithMock(session, 'call_plugin_serialized')
+        session.call_plugin_serialized('nova_plugin_version', 'get_version',
+                            ).AndReturn("3.0")
+
+        self.mox.ReplayAll()
+        self.assertRaises(xenapi_fake.Failure, session._verify_plugin_version)
+
+    def test_verify_plugin_version_bad_min(self):
+        session = self._get_mock_xapisession({})
+        session.XenAPI = xenapi_fake.FakeXenAPI()
+
+        session.PLUGIN_REQUIRED_VERSION = '2.4'
+
+        self.mox.StubOutWithMock(session, 'call_plugin_serialized')
+        session.call_plugin_serialized('nova_plugin_version', 'get_version',
+                            ).AndReturn("2.3")
+
+        self.mox.ReplayAll()
+        self.assertRaises(xenapi_fake.Failure, session._verify_plugin_version)
+
+    def test_verify_current_version_matches(self):
+        session = self._get_mock_xapisession({})
+
+        # Import the plugin to extract its version
+        path = os.path.dirname(__file__)
+        rel_path_elem = "../../../../plugins/xenserver/xenapi/etc/xapi.d/" \
+            "plugins/nova_plugin_version"
+        for elem in rel_path_elem.split('/'):
+            path = os.path.join(path, elem)
+        path = os.path.realpath(path)
+
+        plugin_version = None
+        with open(path) as plugin_file:
+            for line in plugin_file:
+                if "PLUGIN_VERSION = " in line:
+                    print line
+                    plugin_version = line.strip()[17:].strip('"')
+
+        self.assertEquals(session.PLUGIN_REQUIRED_VERSION,
+                          plugin_version)
+
 
 class XenAPIFakeTestCase(test.NoDBTestCase):
     def test_query_matches(self):

nova/virt/xenapi/driver.py

@@ -654,6 +654,12 @@ class XenAPIDriver(driver.ComputeDriver):
 class XenAPISession(object):
     """The session to invoke XenAPI SDK calls."""
 
+    # This is not a config option as it should only ever be
+    # changed in development environments.
+    # MAJOR VERSION: Incompatible changes with the plugins
+    # MINOR VERSION: Compatible changes, new plguins, etc
+    PLUGIN_REQUIRED_VERSION = '1.0'
+
     def __init__(self, url, user, pw, virtapi):
         import XenAPI
         self.XenAPI = XenAPI
@@ -668,6 +674,22 @@ class XenAPISession(object):
             self._get_product_version_and_brand()
         self._virtapi = virtapi
 
+        self._verify_plugin_version()
+
+    def _verify_plugin_version(self):
+        # Verify that we're using the right version of the plugins
+        returned_version = self.call_plugin_serialized(
+            'nova_plugin_version', 'get_version')
+
+        # Can't use vmops.cmp_version because that tolerates differences in
+        # major version
+        req_maj, req_min = self.PLUGIN_REQUIRED_VERSION.split('.')
+        got_maj, got_min = returned_version.split('.')
+        if req_maj != got_maj or req_min > got_min:
+            raise self.XenAPI.Failure(
+                _("Plugin version mismatch (Expected %(exp)s, got %(got)s)") %
+                {'exp': self.PLUGIN_REQUIRED_VERSION, 'got': returned_version})
+
     def _create_first_session(self, url, user, pw, exception):
         try:
             session = self._create_session(url)

nova/virt/xenapi/fake.py

@@ -673,6 +673,9 @@ class SessionBase(object):
             raise Failure('Guest does not have a console')
         return base64.b64encode(zlib.compress("dom_id: %s" % dom_id))
 
+    def _plugin_nova_plugin_version_get_version(self, method, args):
+        return pickle.dumps("1.0")
+
     def host_call_plugin(self, _1, _2, plugin, method, args):
         func = getattr(self, '_plugin_%s_%s' % (plugin, method), None)
         if not func:

plugins/xenserver/xenapi/contrib/rpmbuild/SPECS/openstack-xen-plugins.spec

@@ -42,3 +42,4 @@ rm -rf $RPM_BUILD_ROOT
 /etc/xapi.d/plugins/xenhost
 /etc/xapi.d/plugins/xenstore.py
 /etc/xapi.d/plugins/utils.py
+/etc/xapi.d/plugins/nova_plugin_version

plugins/xenserver/xenapi/etc/xapi.d/plugins/nova_plugin_version

@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2013 OpenStack Foundation
+# Copyright (c) 2013 Citrix Systems, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Returns the version of the nova plugins"""
+
+import utils
+
+# MAJOR VERSION: Incompatible changes
+# MINOR VERSION: Compatible changes, new plugins, etc
+
+# 1.0 - Initial version.
+PLUGIN_VERSION = "1.0"
+
+def get_version(session):
+    return PLUGIN_VERSION
+
+
+if __name__ == '__main__':
+    utils.register_plugin_calls(get_version)