Enhance orchagent and buffer manager in error handling (sonic-net#2414)

What I did
Enhance orchagent and buffer manager

Buffer manager: do not insert buffer queue into cache if the profile is illegal, which prevents an empty string from being inserted into APPL_DB during initialization.
orchagent: handle the case that a field referencing other objects is an empty string.
There had been such logic that was broken by a PR last year.
Signed-off-by: Stephen Sun stephens@nvidia.com

Why I did it
Enhance the error handling logic.
In most cases, a user will not encounter such scenarios in a production environment because it's the front-ends' (eg. CLI) responsibility to identify the wrong configuration and prevent them from being inserted to CONFIG_DB.
However, in some cases, like a wrong config_db.json composed and copied to the switch, front-ends can not prevent that.

How I verified it
Manual and mock tests.

Details if related
For the improvement in buffer manager:

previously, the logic was:
declare a reference portQueue to m_portQueueLookup[port][queues] and then assign fvValue(i) to portQueue.running_profile_name
But [] operation on C++ map has a side-effect -- it will insert a new element into the map if there wasn't one. In case the validation check in checkBufferProfileDirection failed and there was not one in the map, the portQueue.running_profile_name will keep empty. This is not what we want.
In case there was an item configured in the map, we should not remove it on failure because we want to prevent the user from being affected by misconfiguration and alert user to correct the error. There is log in checkBufferProfileDirection
Now it is improved in this way:
Avoid using reference and initialize m_portQueueLookup[port][queues] only if there is a valid egress profile configured

Author: stephenxs

cfgmgr/buffermgrdyn.cpp

@@ -3110,8 +3110,7 @@ task_process_status BufferMgrDynamic::handleSingleBufferQueueEntry(const string
 
     if (op == SET_COMMAND)
     {
-        auto &portQueue = m_portQueueLookup[port][queues];
-
+        bool successful = false;
         SWSS_LOG_INFO("Inserting entry BUFFER_QUEUE_TABLE:%s to APPL_DB", key.c_str());
 
         for (auto i : kfvFieldsValues(tuple))
@@ -3122,8 +3121,10 @@ task_process_status BufferMgrDynamic::handleSingleBufferQueueEntry(const string
                 auto rc = checkBufferProfileDirection(fvValue(i), BUFFER_EGRESS);
                 if (rc != task_process_status::task_success)
                     return rc;
-                portQueue.running_profile_name = fvValue(i);
+
+                m_portQueueLookup[port][queues].running_profile_name = fvValue(i);
                 SWSS_LOG_NOTICE("Queue %s has been configured on the system, referencing profile %s", key.c_str(), fvValue(i).c_str());
+                successful = true;
             }
             else
             {
@@ -3134,8 +3135,15 @@ task_process_status BufferMgrDynamic::handleSingleBufferQueueEntry(const string
             SWSS_LOG_INFO("Inserting field %s value %s", fvField(i).c_str(), fvValue(i).c_str());
         }
 
+        if (!successful)
+        {
+            SWSS_LOG_ERROR("Invalid BUFFER_QUEUE configuration on %s: no profile configured", key.c_str());
+            return task_process_status::task_failed;
+        }
+
         // TODO: check overlap. Currently, assume there is no overlap
 
+        auto &portQueue = m_portQueueLookup[port][queues];
         if (PORT_ADMIN_DOWN == portInfo.state)
         {
             handleSetSingleBufferObjectOnAdminDownPort(BUFFER_QUEUE, port, key, portQueue.running_profile_name);

orchagent/orch.cpp

@@ -393,7 +393,7 @@ ref_resolve_status Orch::resolveFieldRefValue(
             {
                 return ref_resolve_status::not_resolved;
             }
-            else if (ref_type_name.empty() && object_name.empty())
+            else if (object_name.empty())
             {
                 return ref_resolve_status::empty;
             }

tests/mock_tests/buffermgrdyn_ut.cpp

@@ -667,6 +667,13 @@ namespace buffermgrdyn_test
         CheckProfileList("Ethernet0", true, "ingress_lossless_profile", false);
         CheckProfileList("Ethernet0", false, "egress_lossless_profile,egress_lossy_profile", false);
 
+        // Initialize a port with all profiles undefined
+        InitPort("Ethernet8");
+        InitBufferPg("Ethernet8|0", "ingress_not_defined_profile");
+        InitBufferQueue("Ethernet8|0", "egress_not_defined_profile");
+        InitBufferProfileList("Ethernet8", "egress_not_defined_profile", bufferEgrProfileListTable);
+        InitBufferProfileList("Ethernet8", "ingress_not_defined_profile", bufferIngProfileListTable);
+
         // All default buffer profiles should be generated and pushed into BUFFER_PROFILE_TABLE
         static_cast<Orch *>(m_dynamicBuffer)->doTask();
 
@@ -686,6 +693,36 @@ namespace buffermgrdyn_test
         CheckProfileList("Ethernet0", true, "ingress_lossless_profile", true);
         CheckProfileList("Ethernet0", false, "egress_lossless_profile,egress_lossy_profile", true);
 
+        // Check no items applied on port Ethernet8
+        ASSERT_EQ(appBufferPgTable.get("Ethernet8:0", fieldValues), false);
+        CheckQueue("Ethernet8", "Ethernet8:0", "", false);
+        CheckProfileList("Ethernet8", true, "", false);
+        CheckProfileList("Ethernet8", false, "", false);
+
+        // Configure the missing buffer profiles
+        bufferProfileTable.set("ingress_not_defined_profile",
+                               {
+                                   {"pool", "ingress_lossless_pool"},
+                                   {"dynamic_th", "0"},
+                                   {"size", "0"}
+                               });
+        bufferProfileTable.set("egress_not_defined_profile",
+                               {
+                                   {"pool", "egress_lossless_pool"},
+                                   {"dynamic_th", "0"},
+                                   {"size", "0"}
+                               });
+        m_dynamicBuffer->addExistingData(&bufferProfileTable);
+        // For buffer profile
+        static_cast<Orch *>(m_dynamicBuffer)->doTask();
+        // For all other items
+        static_cast<Orch *>(m_dynamicBuffer)->doTask();
+        ASSERT_EQ(appBufferPgTable.get("Ethernet8:0", fieldValues), true);
+        ASSERT_EQ(fvValue(fieldValues[0]), "ingress_not_defined_profile");
+        CheckQueue("Ethernet8", "Ethernet8:0", "egress_not_defined_profile", true);
+        CheckProfileList("Ethernet8", true, "ingress_not_defined_profile", true);
+        CheckProfileList("Ethernet8", false, "egress_not_defined_profile", true);
+
         InitPort("Ethernet4");
         InitPort("Ethernet6");
         InitBufferQueue("Ethernet6|0-2", "egress_lossy_profile");

tests/mock_tests/qosorch_ut.cpp

@@ -1337,4 +1337,35 @@ namespace qosorch_test
 
         testing_wred_thresholds = false;
     }
+
+    /*
+     * Make sure empty fields won't cause orchagent crash
+     */
+    TEST_F(QosOrchTest, QosOrchTestEmptyField)
+    {
+        // Create a new dscp to tc map
+        std::deque<KeyOpFieldsValuesTuple> entries;
+        entries.push_back({"Ethernet0", "SET",
+                            {
+                                {"dscp_to_tc_map", ""}
+                            }});
+        auto consumer = dynamic_cast<Consumer *>(gQosOrch->getExecutor(CFG_PORT_QOS_MAP_TABLE_NAME));
+        consumer->addToSync(entries);
+        entries.clear();
+
+        entries.push_back({"Ethernet0|3", "SET",
+                           {
+                               {"scheduler", ""}
+                           }});
+        entries.push_back({"Ethernet0|4", "SET",
+                           {
+                               {"wred_profile", ""}
+                           }});
+        consumer = dynamic_cast<Consumer *>(gQosOrch->getExecutor(CFG_QUEUE_TABLE_NAME));
+        consumer->addToSync(entries);
+        entries.clear();
+
+        // Drain DSCP_TO_TC_MAP and PORT_QOS_MAP table
+        static_cast<Orch *>(gQosOrch)->doTask();
+    }
 }