[ycabled] fix minor appl_db retrieving logic for update (#319)

Signed-off-by: vaibhav-dahiya vdahiya@microsoft.com
This PR fixes the app DB access fix logic by updating the values causing some failures for ycabled's response for mux probe from linkmgrd.
This PR essentially fixes that logic, calling the correct method to access the app DB
self.appl_db -> self.table_helper.get_appl_db()

Description
Motivation and Context
How Has This Been Tested?
UT and deploying changes to kvm

Additional Information (Optional)

sonic-ycabled/tests/test_y_cable_helper.py

@@ -5798,3 +5798,25 @@ def test_apply_grpc_secrets_configuration(self, open):
             patched_util.return_value = parsed_data
             rc = apply_grpc_secrets_configuration(None)
             assert(rc == None)
+
+
+
+    def test_handle_ycable_active_standby_probe_notification(self):
+
+        test_db = "TEST_DB"
+        status = True
+        port_m = "Ethernet0"
+        fvp_m = [('command', "probe"), ('read_side', 1), ('cable_type','active-standby'), ('soc_ipv4','192.168.0.1')]
+        fvp_dict = {"command": "probe"}
+        hw_mux_cable_tbl = {}
+        y_cable_response_tbl = {}
+        asic_index = 0
+        hw_mux_cable_tbl[asic_index] = swsscommon.Table(
+            test_db[asic_index], "PORT_INFO_TABLE")
+        y_cable_response_tbl[asic_index] = swsscommon.Table(
+            test_db[asic_index], "PORT_INFO_TABLE")
+        hw_mux_cable_tbl[asic_index].get.return_value = (status, fvp_m)
+
+        rc = handle_ycable_active_standby_probe_notification("active-standby", fvp_dict, test_db, hw_mux_cable_tbl, port_m, asic_index, y_cable_response_tbl)
+        assert(rc == True)
+

sonic-ycabled/ycable/ycable_utilities/y_cable_helper.py

@@ -3411,6 +3411,29 @@ def handle_hw_mux_cable_table_grpc_notification(fvp, hw_mux_cable_tbl, asic_inde
             helper_logger.log_info("Got a change event on port {} of table {} that does not contain state".format(
                 port, swsscommon.APP_HW_MUX_CABLE_TABLE_NAME))
 
+
+def handle_ycable_active_standby_probe_notification(cable_type, fvp_dict, appl_db, hw_mux_cable_tbl, port_m, asic_index,  y_cable_response_tbl):
+
+    if cable_type == 'active-standby' and "command" in fvp_dict:
+
+        # check if xcvrd got a probe command
+        probe_identifier = fvp_dict["command"]
+
+        if probe_identifier == "probe":
+
+            (status, fv) = hw_mux_cable_tbl[asic_index].get(port_m)
+
+            if status is False:
+                helper_logger.log_warning("Could not retreive fieldvalue pairs for {}, inside state_db table {}".format(
+                    port_m, hw_mux_cable_tbl[asic_index].getTableName()))
+                return False
+
+            mux_port_dict = dict(fv)
+            read_side = mux_port_dict.get("read_side")
+            update_appdb_port_mux_cable_response_table(port_m, asic_index, appl_db, int(read_side), y_cable_response_tbl)
+
+            return True
+
 def handle_ycable_enable_disable_tel_notification(fvp_m, key):
 
     global disable_telemetry
@@ -3576,21 +3599,8 @@ def task_worker(self):
                     (status, cable_type) = check_mux_cable_port_type(port_m, self.table_helper.get_port_tbl(), asic_index)
 
                     if status:
+                        handle_ycable_active_standby_probe_notification(cable_type, fvp_dict, self.table_helper.get_appl_db(), self.table_helper.get_hw_mux_cable_tbl(), port_m, asic_index, self.table_helper.get_y_cable_response_tbl())
 
-                        if cable_type == 'active-standby' and "command" in fvp_dict:
-
-                            # check if xcvrd got a probe command
-                            probe_identifier = fvp_dict["command"]
-
-                            if probe_identifier == "probe":
-                                (status, fv) = self.table_helper.get_hw_mux_cable_tbl()[asic_index].get(port_m)
-                                if status is False:
-                                    helper_logger.log_warning("Could not retreive fieldvalue pairs for {}, inside state_db table {}".format(
-                                        port_m, self.table_helper.get_hw_mux_cable_tbl()[asic_index].getTableName()))
-                                    continue
-                                mux_port_dict = dict(fv)
-                                read_side = mux_port_dict.get("read_side")
-                                update_appdb_port_mux_cable_response_table(port_m, asic_index, self.appl_db, int(read_side), self.table_helper.get_y_cable_response_tbl())
 
             while True:
                 (port_m, op_m, fvp_m) = self.table_helper.get_fwd_state_command_tbl()[asic_index].pop()