power_status_handler handles missing PSU and all exceptions

Signed-off-by: Qi Luo <qiluo-msft@users.noreply.github.com>

src/sonic_ax_impl/mibs/vendor/cisco/ciscoEntityFruControlMIB.py

@@ -45,7 +45,14 @@ def _getPsuIndex(self, sub_id):
 
         psu_index = int(sub_id[0])
 
-        if psu_index < 1 or psu_index > self.psuutil.get_num_psus():
+        try:
+            num_psus = self.psuutil.get_num_psus()
+        except Exception:
+            # Any unexpected exception or error, log it and keep running
+            logger.exception("PowerStatusHandler._getPsuIndex() caught an unexpected exception during get_num_psus()")
+            return None
+
+        if psu_index < 1 or psu_index > num_psus:
             return None
 
         return psu_index
@@ -62,8 +69,15 @@ def get_next(self, sub_id):
             return (1,)
 
         psu_index = self._getPsuIndex(sub_id)
+        try:
+            num_psus = self.psuutil.get_num_psus()
+        except Exception:
+            # Any unexpected exception or error, log it and keep running
+            logger.exception("PowerStatusHandler.get_next() caught an unexpected exception during get_num_psus()")
+            return None
 
-        if psu_index and psu_index + 1 <= self.psuutil.get_num_psus():
+
+        if psu_index and psu_index + 1 <= num_psus:
             return (psu_index + 1,)
 
         return None
@@ -74,19 +88,35 @@ def getPsuStatus(self, sub_id):
         :return: the status of requested PSU according to cefcModuleOperStatus ModuleOperType
                  2 - PSU has correct functionalling - ok
                  7 - PSU has a problem with functionalling - failed
+                 8 - the module is provisioned, but it is missing. This is a failure state.
         :ref: https://www.cisco.com/c/en/us/td/docs/switches/wan/mgx/mgx_8850/software/mgx_r2-0-10/pxm/reference/guide/pxm/cscoent.html
         """
         psu_index = self._getPsuIndex(sub_id)
 
         if not psu_index:
             return None
 
-        psu_status = self.psuutil.get_psu_status(psu_index)
+        try:
+            psu_presence = self.psuutil.get_psu_presence(psu_index)
+        except Exception:
+            # Any unexpected exception or error, log it and keep running
+            logger.exception("PowerStatusHandler.getPsuStatus() caught an unexpected exception during get_psu_presence()")
+            return None
+
+        if psu_presence:
+            try:
+                psu_status = self.psuutil.get_psu_status(psu_index)
+            except Exception:
+                # Any unexpected exception or error, log it and keep running
+                logger.exception("PowerStatusHandler.getPsuStatus() caught an unexpected exception during get_psu_status()")
+                return None
 
-        if psu_status:
-            return 2
+            if psu_status:
+                return 2
 
-        return 7
+            return 7
+        else:
+            return 8
 
 
 class cefcFruPowerStatusTable(metaclass=MIBMeta, prefix='.1.3.6.1.4.1.9.9.117.1.1.2'):

tests/plugins/psuutil.py

@@ -13,8 +13,9 @@ class PsuUtil():
 
     def __init__(self):
         """ For testing purpose only """
-        self.num_of_psus = 2
-        self.psu_status = { 1 : True, 2 : False }
+        self.num_of_psus = 3
+        self.psu_status = { 1: False, 2: True, 3: False }
+        self.psu_presence = { 1: False, 2: True, 3: True }
 
     def get_num_psus(self):
         """
@@ -37,7 +38,10 @@ def get_psu_status(self, index):
         if not isinstance(index, int):
             return False
         elif index > 0 and index <= self.num_of_psus:
-            return self.psu_status[index]
+            if self.psu_presence[index]:
+                return self.psu_status[index]
+            else:
+                raise ValueError(index)
         else:
             return False
 
@@ -53,6 +57,6 @@ def get_psu_presence(self, index):
         if not isinstance(index, int):
             return False
         elif index > 0 and index <= self.num_of_psus:
-            return self.psu_status[index]
+            return self.psu_presence[index]
         else:
             return False

tests/test_psu.py

@@ -22,6 +22,22 @@ class TestPsuStatus(TestCase):
     def setUpClass(cls):
         cls.lut = MIBTable(ciscoEntityFruControlMIB.cefcFruPowerStatusTable)
 
+    def test_getNextPsu0(self):
+        oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2))
+        expected_oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 1))
+        get_pdu = GetNextPDU(
+            header=PDUHeader(1, PduTypes.GET_NEXT, 16, 0, 42, 0, 0, 0),
+            oids=[oid]
+        )
+
+        encoded = get_pdu.encode()
+        response = get_pdu.make_response(self.lut)
+
+        value0 = response.values[0]
+        self.assertEqual(value0.type_, ValueType.INTEGER)
+        self.assertEqual(str(value0.name), str(expected_oid))
+        self.assertEqual(value0.data, 8)
+
     def test_getPsu1Status(self):
         oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 1))
         get_pdu = GetPDU(
@@ -35,7 +51,7 @@ def test_getPsu1Status(self):
         value0 = response.values[0]
         self.assertEqual(value0.type_, ValueType.INTEGER)
         self.assertEqual(str(value0.name), str(oid))
-        self.assertEqual(value0.data, 2)
+        self.assertEqual(value0.data, 8)
 
     def test_getNextPsu1(self):
         oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 1))
@@ -51,7 +67,7 @@ def test_getNextPsu1(self):
         value0 = response.values[0]
         self.assertEqual(value0.type_, ValueType.INTEGER)
         self.assertEqual(str(value0.name), str(expected_oid))
-        self.assertEqual(value0.data, 7)
+        self.assertEqual(value0.data, 2)
 
     def test_getPsu2Status(self):
         oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 2))
@@ -66,10 +82,10 @@ def test_getPsu2Status(self):
         value0 = response.values[0]
         self.assertEqual(value0.type_, ValueType.INTEGER)
         self.assertEqual(str(value0.name), str(oid))
-        self.assertEqual(value0.data, 7)
+        self.assertEqual(value0.data, 2)
 
-    def test_getNextPsu2(self):
-        oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 2))
+    def test_getNextPsu3(self):
+        oid = ObjectIdentifier(2, 0, 0, 0, (1, 3, 6, 1, 4, 1, 9, 9, 117, 1, 1, 2, 1, 2, 3))
         expected_oid = None
         get_pdu = GetNextPDU(
             header=PDUHeader(1, PduTypes.GET_NEXT, 16, 0, 42, 0, 0, 0),