Handle errors from run_ofctl() when dumping flows

The function dump_flows_for_table() calls run_ofctl(). If this occurs during an OVS
restart, run_ofctl() will return None. dump_flows_for_table() needs to realize this
and not try to call splitlines() on a None object.

Change-Id: Ide26028656e634113f955dfc89569149d4d5b306
Closes-Bug: #1324659

diff --git a/neutron/agent/linux/ovs_lib.py b/neutron/agent/linux/ovs_lib.py
index d5bf42e0b5bf5286724a3502171930e5d20e0e45..9c80d7c8530438b0effff9411565193cf902634d 100644 (file)
--- a/neutron/agent/linux/ovs_lib.py
+++ b/neutron/agent/linux/ovs_lib.py
@@ -204,10 +204,12 @@ class OVSBridge(BaseOVS):
             self.run_ofctl("del-flows", [flow_expr_str])
 
     def dump_flows_for_table(self, table):
+        retval = None
         flow_str = "table=%s" % table
         flows = self.run_ofctl("dump-flows", [flow_str])
-        retval = '\n'.join(item for item in flows.splitlines()
-                           if 'NXST' not in item)
+        if flows:
+            retval = '\n'.join(item for item in flows.splitlines()
+                               if 'NXST' not in item)
         return retval
 
     def defer_apply_on(self):

diff --git a/neutron/tests/unit/agent/linux/test_ovs_lib.py b/neutron/tests/unit/agent/linux/test_ovs_lib.py
index a1daa22a01b08be16a3f6ce0cb72107806382ac0..a11cd02556a0c608d5b108145e658787efac5f31 100644 (file)
--- a/neutron/tests/unit/agent/linux/test_ovs_lib.py
+++ b/neutron/tests/unit/agent/linux/test_ovs_lib.py
@@ -367,6 +367,34 @@ class OVS_Lib_Test(base.BaseTestCase):
                           self.br.delete_flows,
                           **params)
 
+    def test_dump_flows(self):
+        table = 23
+        nxst_flow = "NXST_FLOW reply (xid=0x4):"
+        flows = "\n".join([" cookie=0x0, duration=18042.514s, table=0, "
+                           "n_packets=6, n_bytes=468, "
+                           "priority=2,in_port=1 actions=drop",
+                           " cookie=0x0, duration=18027.562s, table=0, "
+                           "n_packets=0, n_bytes=0, "
+                           "priority=3,in_port=1,dl_vlan=100 "
+                           "actions=mod_vlan_vid:1,NORMAL",
+                           " cookie=0x0, duration=18044.351s, table=0, "
+                           "n_packets=9, n_bytes=594, priority=1 "
+                           "actions=NORMAL", " cookie=0x0, "
+                           "duration=18044.211s, table=23, n_packets=0, "
+                           "n_bytes=0, priority=0 actions=drop"])
+        flow_args = '\n'.join([nxst_flow, flows])
+        run_ofctl = mock.patch.object(self.br, 'run_ofctl').start()
+        run_ofctl.side_effect = [flow_args]
+        retflows = self.br.dump_flows_for_table(table)
+        self.assertEqual(flows, retflows)
+
+    def test_dump_flows_ovs_dead(self):
+        table = 23
+        run_ofctl = mock.patch.object(self.br, 'run_ofctl').start()
+        run_ofctl.side_effect = ['']
+        retflows = self.br.dump_flows_for_table(table)
+        self.assertEqual(None, retflows)
+
     def test_mod_flow_with_priority_set(self):
         params = {'in_port': '1',
                   'priority': '1'}