Rework nova_cell_v2_discover_host.py to use nova.conf and python novaclient

Previously nova_cell_v2_discover_host.py used environment variables passed
to the script and it got deleted right after usage. This changed to:
- read auth information from nova.conf
- read host information from nova.conf
- use python novaclient to check new services instead of subprocess
calls

Change-Id: Id08be90d6be89af66d94bc779f311702526eb788

docker_config_scripts/nova_cell_v2_discover_host.py

@@ -14,73 +14,80 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 from __future__ import print_function
+
+import logging
+from optparse import OptionParser
 import os
-import pwd
 import socket
 import subprocess
 import sys
 import time
 
-# Delete this immediataly as it contains auth info
-os.unlink(__file__)
 
-# Only need root to read this script, drop to nova user
-nova_uid, nova_gid = pwd.getpwnam('nova')[2:4]
-os.setgid(nova_gid)
-os.setuid(nova_uid)
+from keystoneauth1 import loading
+from keystoneauth1 import session
 
+from novaclient import client
 
-os.environ.update(
-    OS_PROJECT_DOMAIN_NAME='__OS_PROJECT_DOMAIN_NAME',
-    OS_USER_DOMAIN_NAME='__OS_PROJECT_USER_NAME',
-    OS_PROJECT_NAME='__OS_PROJECT_NAME',
-    OS_USERNAME='__OS_USERNAME',
-    OS_PASSWORD='__OS_PASSWORD',
-    OS_AUTH_URL='__OS_AUTH_URL',
-    OS_AUTH_TYPE='password',
-    OS_IDENTITY_API_VERSION='3'
-)
+from six.moves.configparser import SafeConfigParser
 
-try:
-    my_host = subprocess.check_output([
-        'crudini',
-        '--get',
-        '/etc/nova/nova.conf',
-        'DEFAULT',
-        'host'
-    ], universal_newlines=True).rstrip()
-except subprocess.CalledProcessError:
+logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
+LOG = logging.getLogger('nova_cell_v2_discover_host')
+
+nova_cfg = '/etc/nova/nova.conf'
+
+if __name__ == '__main__':
+    parser = OptionParser(usage="usage: %prog [options]")
+    parser.add_option('-k', '--insecure',
+                      action="store_false",
+                      dest='insecure',
+                      default=True,
+                      help='Allow insecure connection when using SSL')
+
+    (options, args) = parser.parse_args()
+    LOG.debug('Running with parameter insecure = %s',
+              options.insecure)
+
+    if os.path.isfile(nova_cfg):
+        config = SafeConfigParser()
+        config.read(nova_cfg)
+    else:
+        LOG.error('Nova configuration file %s does not exist', nova_cfg)
+        sys.exit(1)
+
+    my_host = config.get('DEFAULT', 'host')
+    if not my_host:
         # If host isn't set nova defaults to this
         my_host = socket.gethostname()
 
+    loader = loading.get_plugin_loader('password')
+    auth = loader.load_from_options(
+        auth_url=config.get('neutron',
+                            'auth_url'),
+        username=config.get('neutron',
+                            'username'),
+        password=config.get('neutron',
+                            'password'),
+        project_name=config.get('neutron',
+                                'project_name'),
+        project_domain_name=config.get('neutron',
+                                       'project_domain_name'),
+        user_domain_name=config.get('neutron',
+                                    'user_domain_name'))
+    sess = session.Session(auth=auth, verify=options.insecure)
+    nova = client.Client('2.11', session=sess, endpoint_type='internal')
+
     # Wait until this host is listed in the service list then
     # run cellv2 host discovery
     retries = 10
     for i in range(retries):
         try:
-        service_output = subprocess.check_output([
-            'openstack',
-            '-q',
-            '--os-interface',
-            'internal',
-            'compute',
-            'service',
-            'list',
-            '-c',
-            'Host',
-            '-c',
-            'Zone',
-            '-f',
-            'value'
-        ], universal_newlines=True)
-        service_list = service_output.split('\n')
+            service_list = nova.services.list(binary='nova-compute')
             for entry in service_list:
-            # skip any empty lines
-            if not entry:
-                continue
-            host, zone = entry.split()
+                host = getattr(entry, 'host', '')
+                zone = getattr(entry, 'zone', '')
                 if host == my_host and zone != 'internal':
-                print('(cellv2) Service registered, running discovery')
+                    LOG.info('(cellv2) Service registered, running discovery')
                     sys.exit(subprocess.call([
                         '/usr/bin/nova-manage',
                         'cell_v2',
@@ -88,8 +95,15 @@ for i in range(retries):
                         '--by-service',
                         '--verbose'
                     ]))
-        print('(cellv2) Waiting for service to register')
+                if len(service_list) == 0:
+                    LOG.warning('(cellv2) no nova-compute service registered' +
+                                ' after %i checks', i)
+            LOG.info('(cellv2) Waiting for service to register')
         except subprocess.CalledProcessError:
-        print('(cellv2) Retrying')
+            LOG.info('(cellv2) Retrying')
+        except Exception as e:
+            LOG.exception('Error during host discovery:')
         time.sleep(30)
 sys.exit(1)
+
+# vim: set et ts=4 sw=4 :