Add proper support for deprecation messages

Add support for warning once about deprecated options. Use that in
the rootwrap options deprecation message, and move it to run_as_root
so that the deprecated message is emitted once and only if used.

Change-Id: I29e39c662b4456256f4c9397f305bfa857972c46

cinder/common/deprecated.py

@@ -0,0 +1,55 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright (c) 2012 IBM
+#
+#    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.
+
+import warnings
+
+from cinder import exception
+from cinder import flags
+from cinder.openstack.common import cfg
+from cinder.openstack.common import log as logging
+
+LOG = logging.getLogger(__name__)
+
+deprecate_opts = [
+    cfg.BoolOpt('fatal_deprecations',
+                default=False,
+                help='make deprecations fatal')
+    ]
+FLAGS = flags.FLAGS
+FLAGS.register_opts(deprecate_opts)
+
+
+def _showwarning(message, category, filename, lineno, file=None, line=None):
+    """
+    Redirect warnings into logging.
+    """
+    LOG.warn(str(message))
+
+
+# Install our warnings handler
+warnings.showwarning = _showwarning
+
+
+def warn(msg=""):
+    """
+    Warn of a deprecated config option that an operator has specified.
+    This should be added in the code where we've made a change in how
+    we use some operator changeable parameter to indicate that it will
+    go away in a future version of OpenStack.
+    """
+    warnings.warn(_("Deprecated Config: %s") % msg)
+    if FLAGS.fatal_deprecations:
+        raise exception.DeprecatedConfig(msg=msg)

cinder/exception.py

@@ -171,6 +171,10 @@ class CinderException(Exception):
         super(CinderException, self).__init__(message)
 
 
+class DeprecatedConfig(CinderException):
+    message = _("Fatal call to deprecated config") + " %(msg)s"
+
+
 class DecryptionFailure(CinderException):
     message = _("Failed to decrypt text")
 

cinder/tests/test_deprecated.py

@@ -0,0 +1,46 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+#
+#    Copyright 2010 OpenStack LLC
+#
+#    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.
+
+from cinder.common import deprecated
+from cinder import exception
+from cinder import test
+
+
+class DeprecatedConfigTestCase(test.TestCase):
+    def setUp(self):
+        super(DeprecatedConfigTestCase, self).setUp()
+        self.logbuffer = ""
+
+        def local_log(msg):
+            self.logbuffer = msg
+
+        self.stubs.Set(deprecated.LOG, 'warn', local_log)
+
+    def test_deprecated(self):
+        deprecated.warn('test')
+        self.assertEqual(self.logbuffer, 'Deprecated Config: test')
+
+    def test_deprecated_fatal(self):
+        self.flags(fatal_deprecations=True)
+        self.assertRaises(exception.DeprecatedConfig,
+                          deprecated.warn, "test2")
+        self.assertEqual(self.logbuffer, 'Deprecated Config: test2')
+
+    def test_deprecated_logs_only_once(self):
+        deprecated.warn('only once!')
+        deprecated.warn('only once!')
+        deprecated.warn('only once!')
+        self.assertEqual(self.logbuffer, 'Deprecated Config: only once!')

cinder/utils.py

@@ -46,6 +46,7 @@ from eventlet import greenthread
 from eventlet.green import subprocess
 import netaddr
 
+from cinder.common import deprecated
 from cinder import exception
 from cinder import flags
 from cinder.openstack.common import log as logging
@@ -59,12 +60,6 @@ ISO_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
 PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
 FLAGS = flags.FLAGS
 
-if FLAGS.rootwrap_config is None or FLAGS.root_helper != 'sudo':
-    LOG.warn(_('The root_helper option (which lets you specify a root '
-               'wrapper different from cinder-rootwrap, and defaults to '
-               'using sudo) is now deprecated. You should use the '
-               'rootwrap_config option instead.'))
-
 
 def find_config(config_path):
     """Find a configuration file using the given hint.
@@ -187,6 +182,14 @@ def execute(*cmd, **kwargs):
                                 'to utils.execute: %r') % kwargs)
 
     if run_as_root:
+
+        if FLAGS.rootwrap_config is None or FLAGS.root_helper != 'sudo':
+            deprecated.warn(_('The root_helper option (which lets you specify '
+                              'a root wrapper different from cinder-rootwrap, '
+                              'and defaults to using sudo) is now deprecated. '
+                              'You should use the rootwrap_config option '
+                              'instead.'))
+
         if (FLAGS.rootwrap_config is not None):
             cmd = ['sudo', 'cinder-rootwrap',
                    FLAGS.rootwrap_config] + list(cmd)