[thermalctld] Use platform API for PSU fan name

sonic-thermalctld/scripts/thermalctld

@@ -201,6 +201,14 @@ class FanUpdater(logger.Logger):
         self.drawer_table = swsscommon.Table(state_db, FanUpdater.FAN_DRAWER_INFO_TABLE_NAME)
         self.phy_entity_table = swsscommon.Table(state_db, PHYSICAL_ENTITY_INFO_TABLE)
 
+    def get_psu_key(self, psu_index):
+        if self.chassis is not None:
+            try:
+                return self.chassis.get_psu(psu_index).get_name()
+            except (NotImplementedError, AttributeError):
+                pass
+        return 'PSU {}'.format(psu_index + 1)
+
     def __del__(self):
         if self.table:
             table_keys = self.table.getKeys()
@@ -308,7 +316,7 @@ class FanUpdater(logger.Logger):
         """
         drawer_name = NOT_AVAILABLE if fan_type != FanType.DRAWER else str(try_get(parent.get_name))
         if fan_type == FanType.PSU:
-            parent_name = try_get(parent.get_name, default='PSU {}'.format(parent_index + 1))
+            parent_name = self.get_psu_key(parent_index)
         elif fan_type == FanType.MODULE:
             parent_name = try_get(parent.get_name, default='Module {}'.format(parent_index + 1))
         else:

sonic-thermalctld/tests/test_thermalctld.py

@@ -289,6 +289,37 @@ def test_update_module_fans(self):
         else:
             fan_updater.log_warning.assert_called_with("Failed to update module fan status - Exception('Test message',)")
 
+    def test_get_psu_key_returns_psu_name(self):
+        """Test get_psu_key returns PSU name from platform API"""
+        chassis = MockChassis()
+        psu = MockPsu()
+        psu._name = 'PSU0'
+        chassis._psu_list.append(psu)
+        fan_updater = thermalctld.FanUpdater(chassis, threading.Event())
+        assert fan_updater.get_psu_key(0) == 'PSU0'
+
+    def test_get_psu_key_attribute_error(self):
+        """Test get_psu_key falls back when get_psu returns None (AttributeError on .get_name())"""
+        chassis = MockChassis()
+        # No PSUs added, so get_psu(index) returns None and .get_name() raises AttributeError
+        fan_updater = thermalctld.FanUpdater(chassis, threading.Event())
+        assert fan_updater.get_psu_key(0) == 'PSU 1'
+        assert fan_updater.get_psu_key(1) == 'PSU 2'
+
+    def test_get_psu_key_not_implemented_error(self):
+        """Test get_psu_key falls back to 1-based 'PSU <index+1>' when get_name raises NotImplementedError"""
+        chassis = MockChassis()
+        psu = MockPsu()
+        psu.get_name = mock.MagicMock(side_effect=NotImplementedError)
+        chassis._psu_list.append(psu)
+        fan_updater = thermalctld.FanUpdater(chassis, threading.Event())
+        assert fan_updater.get_psu_key(0) == 'PSU 1'
+
+    def test_get_psu_key_chassis_none(self):
+        """Test get_psu_key falls back to 1-based 'PSU <index+1>' when chassis is None"""
+        fan_updater = thermalctld.FanUpdater(None, threading.Event())
+        assert fan_updater.get_psu_key(0) == 'PSU 1'
+
 class TestLiquidCoolingUpdater(object):
     def test_update(self):
         mock_chassis = MockChassis()