Fix nodepool --version

Currently, the `nodepool --version` command prints a usage message
followed by 'nodepool: error: too few arguments' because we are
not specifying a subcommand. The proper way to do this is to use the
version action in argparser rather than store_true with some logic.

Add version_info so it can successfully be imported and a version
action to print the imported string.

Change-Id: Ic5437d508b27fe4a8e02361cfe345c1f741d3c48

nodepool/cmd/nodepoolcmd.py

@@ -21,6 +21,7 @@ import time
 
 from nodepool import nodedb
 from nodepool import nodepool
+from nodepool.version import version_info as npc_version_info
 from prettytable import PrettyTable
 
 
@@ -33,7 +34,8 @@ class NodePoolCmd(object):
         parser.add_argument('-c', dest='config',
                             default='/etc/nodepool/nodepool.yaml',
                             help='path to config file')
-        parser.add_argument('--version', dest='version', action='store_true',
+        parser.add_argument('--version', action='version',
+                            version=npc_version_info.version_string(),
                             help='show version')
         parser.add_argument('--debug', dest='debug', action='store_true',
                             help='show DEBUG level logging')
@@ -316,11 +318,6 @@ class NodePoolCmd(object):
         self.pool.deleteImage(self.args.id)
 
     def main(self):
-        if self.args.version:
-            from nodepool.version import version_info as npc_version_info
-            print "Nodepool version: %s" % npc_version_info.version_string()
-            return(0)
-
         self.pool = nodepool.NodePool(self.args.config)
         config = self.pool.loadConfig()
         self.pool.reconfigureDatabase(config)

nodepool/version.py

@@ -0,0 +1,17 @@
+#    Copyright 2014 Hewlett-Packard Development Company, L.P.
+#
+#    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 pbr.version
+
+version_info = pbr.version.VersionInfo('nodepool')