Change nova-dhcpbridge FLAGFILE to a list of files

This patch adds support to linux_net and nova-dhcpbridge for
specifying and conveying multiple dhcpbridge_flagfile values.
The support is implemented as follows:

dhcpbridge_flagfile is now a "MultiStr" configuration file option
allowing the flag files to be defined over multiple configuration files.
The configured files are concatenated into a comma separated string and
assigned to the FLAGFILE environment variable when invoking
nova-dhcpbridge. nova-dhcpbridge splits the value of the environment
variable on the comma an initializes its configuration with the provided
files (the configuration system already supports loading configuration
from multiple files)

Fixes bug 1131932

Change-Id: Ic9cc57b8f7d9356606b9134ef5b63ab07b6099d9

4 files changed, 11 insertions, 7 deletions

diff --git a/bin/nova-dhcpbridge b/bin/nova-dhcpbridge
index c00578821..1acaf4cd1 100755
--- a/bin/nova-dhcpbridge
+++ b/bin/nova-dhcpbridge
@@ -42,6 +42,7 @@ from nova import context
 from nova import db
 from nova.network import rpcapi as network_rpcapi
 from nova.openstack.common import importutils
+from nova.openstack.common import jsonutils
 from nova.openstack.common import log as logging
 from nova.openstack.common import rpc
 
@@ -121,7 +122,8 @@ def main():
     except KeyError:
         config_file = os.environ['FLAGFILE']
 
-    config.parse_args(sys.argv, default_config_files=[config_file])
+    config.parse_args(sys.argv,
+        default_config_files=jsonutils.loads(config_file))
 
     logging.setup("nova")
 
diff --git a/etc/nova/nova.conf.sample b/etc/nova/nova.conf.sample
index 9cbb8c1a5..a094469f7 100644
--- a/etc/nova/nova.conf.sample
+++ b/etc/nova/nova.conf.sample
@@ -970,7 +970,7 @@
 # Options defined in nova.network.linux_net
 #
 
-# location of flagfile for dhcpbridge (string value)
+# location of flagfile(s) for dhcpbridge (multi valued)
 #dhcpbridge_flagfile=/etc/nova/nova-dhcpbridge.conf
 
 # Location to keep network config files (string value)
diff --git a/nova/network/linux_net.py b/nova/network/linux_net.py
index 29b882a02..5c20f9ce8 100644
--- a/nova/network/linux_net.py
+++ b/nova/network/linux_net.py
@@ -31,6 +31,7 @@ from nova import db
 from nova import exception
 from nova.openstack.common import fileutils
 from nova.openstack.common import importutils
+from nova.openstack.common import jsonutils
 from nova.openstack.common import lockutils
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
@@ -41,9 +42,9 @@ LOG = logging.getLogger(__name__)
 
 
 linux_net_opts = [
-    cfg.StrOpt('dhcpbridge_flagfile',
-               default='/etc/nova/nova-dhcpbridge.conf',
-               help='location of flagfile for dhcpbridge'),
+    cfg.MultiStrOpt('dhcpbridge_flagfile',
+                    default=['/etc/nova/nova-dhcpbridge.conf'],
+                    help='location of flagfiles for dhcpbridge'),
     cfg.StrOpt('networks_path',
                default=paths.state_path_def('networks'),
                help='Location to keep network config files'),
@@ -994,7 +995,7 @@ def restart_dhcp(context, dev, network_ref):
             LOG.debug(_('Pid %d is stale, relaunching dnsmasq'), pid)
 
     cmd = ['env',
-           'CONFIG_FILE=%s' % CONF.dhcpbridge_flagfile,
+           'CONFIG_FILE=%s' % jsonutils.dumps(CONF.dhcpbridge_flagfile),
            'NETWORK_ID=%s' % str(network_ref['id']),
            'dnsmasq',
            '--strict-order',
diff --git a/nova/tests/network/test_linux_net.py b/nova/tests/network/test_linux_net.py
index cba08d9ce..4eac0c88c 100644
--- a/nova/tests/network/test_linux_net.py
+++ b/nova/tests/network/test_linux_net.py
@@ -26,6 +26,7 @@ from nova import db
 from nova.network import driver
 from nova.network import linux_net
 from nova.openstack.common import fileutils
+from nova.openstack.common import jsonutils
 from nova.openstack.common import log as logging
 from nova.openstack.common import timeutils
 from nova import test
@@ -496,7 +497,7 @@ class LinuxNetworkTestCase(test.TestCase):
         dev = 'br100'
         linux_net.restart_dhcp(self.context, dev, network_ref)
         expected = ['env',
-          'CONFIG_FILE=%s' % CONF.dhcpbridge_flagfile,
+          'CONFIG_FILE=%s' % jsonutils.dumps(CONF.dhcpbridge_flagfile),
           'NETWORK_ID=fake',
           'dnsmasq',
           '--strict-order',