ovs-xapi-sync: Cache nicira-bridge-id in ovs-xapi-sync.

Communicating with xapi from Python can be quite expensive so it
makes sense to cache this data if convenient.

Signed-off-by: Ethan Jackson <ethan@nicira.com>

diff --git a/xenserver/usr_share_openvswitch_scripts_ovs-xapi-sync b/xenserver/usr_share_openvswitch_scripts_ovs-xapi-sync
index 79a6bde..585a894 100755 (executable)
--- a/xenserver/usr_share_openvswitch_scripts_ovs-xapi-sync
+++ b/xenserver/usr_share_openvswitch_scripts_ovs-xapi-sync
@@ -192,14 +192,6 @@ def update_in_band_mgmt(row):
         row.other_config = other_config
 
 
-def update_bridge_id(row):
-    id_ = get_bridge_id(row.name, row.external_ids.get("xs-network-uuids"))
-    if not id_:
-        return
-
-    set_external_id(row, "bridge-id", id_.split(";")[0])
-
-
 def keep_table_columns(schema, table_name, columns):
     table = schema.tables.get(table_name)
     if not table:
@@ -264,7 +256,7 @@ def main():
 
     signal.signal(signal.SIGHUP, handler)
 
-    bridges = {}                # Map from bridge name to xs_network_uuids
+    bridges = {}                # Map from bridge name to nicira-bridge-id
     iface_ids = {}              # Map from xs-vif-uuid to iface-id
     vm_ids = {}                 # Map from xs-vm-uuid to vm-id
     seqno = idl.change_seqno    # Sequence number when we last processed the db
@@ -288,15 +280,22 @@ def main():
 
         new_bridges = {}
         for row in idl.tables["Bridge"].rows.itervalues():
-            old_xnu = bridges.get(row.name)
-            new_xnu = row.external_ids.get("xs-network-uuids", "")
-            if old_xnu is None:
+            if row.name in bridges:
+                nbd = bridges[row.name]
+            else:
                 # New bridge.
                 update_fail_mode(row)
                 update_in_band_mgmt(row)
+                nbd = get_bridge_id(row.name)
+
+            bridge_id = nbd
+            if bridge_id is None:
+                bridge_id = row.external_ids.get("xs-network-uuids")
+
+            if bridge_id is not None:
+                set_external_id(row, "bridge-id", bridge_id.split(";")[0])
 
-            update_bridge_id(row)
-            new_bridges[row.name] = new_xnu
+            new_bridges[row.name] = nbd
         bridges = new_bridges
 
         iface_by_name = {}