Modular chassis: Psud set master led on first run (sonic-net#206)

On first run, the PSU master-led on supervisor of modular-chassis is not set.

Description
The PSU master-led on modular chassis indicates the power-buget status. Similar to individual PSU leds that are set on first_run, the master-led also will be set to based on initial status (RED or GREEN with LED status ON).

Motivation and Context
Without the forced setting of first_run, the master-led status will default to per vendor default. In some cases, this could be amber blinking etc

sonic-psud/scripts/psud

@@ -175,6 +175,7 @@ class PsuChassisInfo(logger.Logger):
         super(PsuChassisInfo, self).__init__(log_identifier)
 
         self.chassis = chassis
+        self.first_run = True
         self.master_status_good = True
         self.total_consumed_power = 0.0
         self.total_supplied_power = 0.0
@@ -242,30 +243,30 @@ class PsuChassisInfo(logger.Logger):
         chassis_tbl.set(CHASSIS_INFO_POWER_KEY_TEMPLATE.format(1), fvs)
 
     def update_master_status(self):
-        if not self.total_supplied_power or not self.total_consumed_power:
-            if self.master_status_good is not True:
-                self.master_status_good = True
-            return False
-
-        master_status_good = (self.total_consumed_power < self.total_supplied_power)
-        if master_status_good == self.master_status_good:
-            return False
+        set_led = self.first_run
+        master_status_good = False
 
-        self.master_status_good = master_status_good
+        if self.total_supplied_power != 0.0 and self.total_consumed_power != 0.0:
+            master_status_good = (self.total_consumed_power < self.total_supplied_power)
+            if master_status_good != self.master_status_good:
+                set_led = True
 
-        # Update the PSU master status LED
-        # set_status_master_led() is a class method implemented in PsuBase
-        # so we do not need to catch NotImplementedError here
-        color = Psu.STATUS_LED_COLOR_GREEN if master_status_good else Psu.STATUS_LED_COLOR_RED
-        Psu.set_status_master_led(color)
+            self.master_status_good = master_status_good
 
-        log_on_status_changed(self, self.master_status_good,
-                              'PSU supplied power warning cleared: supplied power is back to normal.',
-                              'PSU supplied power warning: {}W supplied-power less than {}W consumed-power'.format(
-                                  self.total_supplied_power, self.total_consumed_power)
-                              )
+        if set_led:
+            # Update the PSU master status LED
+            # set_status_master_led() is a class method implemented in PsuBase
+            # so we do not need to catch NotImplementedError here
+            color = Psu.STATUS_LED_COLOR_GREEN if master_status_good else Psu.STATUS_LED_COLOR_RED
+            Psu.set_status_master_led(color)
+
+            log_on_status_changed(self, self.master_status_good,
+                                  'PSU supplied power warning cleared: supplied power is back to normal.',
+                                  'PSU supplied power warning: {}W supplied-power less than {}W consumed-power'.format(
+                                      self.total_supplied_power, self.total_consumed_power)
+                                  )
 
-        return True
+        return set_led
 
 # PSU status ===================================================================
 #
@@ -605,6 +606,9 @@ class DaemonPsud(daemon_base.DaemonBase):
         self.psu_chassis_info.run_power_budget(self.chassis_tbl)
         self.psu_chassis_info.update_master_status()
 
+        if self.first_run:
+            self.first_run = False
+
 
 #
 # Main =========================================================================

sonic-psud/tests/test_PsuChassisInfo.py

@@ -65,6 +65,7 @@ def test_update_master_status(self):
         chassis = MockChassis()
         chassis_info = psud.PsuChassisInfo(SYSLOG_IDENTIFIER, chassis)
 
+        # With first_run set as True
         # Test good values while in bad state
         chassis_info.total_supplied_power = 510.0
         chassis_info.total_consumed_power = 350.0
@@ -75,13 +76,44 @@ def test_update_master_status(self):
 
         # Test good values while in good state
         ret = chassis_info.update_master_status()
-        assert ret == False
+        assert ret == True
         assert chassis_info.master_status_good == True
 
         # Test unknown total_supplied_power (0.0)
         chassis_info.total_supplied_power = 0.0
         chassis_info.master_status_good = False
         ret = chassis_info.update_master_status()
+        assert ret == True
+        assert chassis_info.master_status_good == False
+
+        # Test bad values while in good state
+        chassis_info.total_supplied_power = 300.0
+        chassis_info.total_consumed_power = 350.0
+        chassis_info.master_status_good = True
+        ret = chassis_info.update_master_status()
+        assert ret == True
+        assert chassis_info.master_status_good == False
+
+        # With first_run set as False
+        chassis_info.first_run = False
+
+        # Test good values while in bad state
+        chassis_info.total_supplied_power = 510.0
+        chassis_info.total_consumed_power = 350.0
+        chassis_info.master_status_good = False
+        ret = chassis_info.update_master_status()
+        assert ret == True
+        assert chassis_info.master_status_good == True
+
+        # Test good values while in good state
+        ret = chassis_info.update_master_status()
+        assert ret == False
+        assert chassis_info.master_status_good == True
+
+        # Test unknown total_supplied_power (0.0)
+        chassis_info.total_supplied_power = 0.0
+        chassis_info.master_status_good = True
+        ret = chassis_info.update_master_status()
         assert ret == False
         assert chassis_info.master_status_good == True
 
@@ -91,7 +123,7 @@ def test_update_master_status(self):
         chassis_info.master_status_good = False
         ret = chassis_info.update_master_status()
         assert ret == False
-        assert chassis_info.master_status_good == True
+        assert chassis_info.master_status_good == False
 
         # Test bad values while in good state
         chassis_info.total_supplied_power = 300.0
@@ -106,6 +138,7 @@ def test_update_master_status(self):
         assert ret == False
         assert chassis_info.master_status_good == False
 
+
     def test_supplied_power(self):
         chassis = MockChassis()
         psu1 = MockPsu("PSU 1", 0, True, True)
@@ -204,6 +237,7 @@ def test_power_budget(self):
         state_db = daemon_base.db_connect("STATE_DB")
         chassis_tbl = mock_swsscommon.Table(state_db, CHASSIS_INFO_TABLE)
         chassis_info = psud.PsuChassisInfo(SYSLOG_IDENTIFIER, chassis)
+        chassis_info.first_run = False
 
         # Check case where supplied_power < consumed_power
         chassis_info.run_power_budget(chassis_tbl)
@@ -237,6 +271,24 @@ def test_power_budget(self):
         # so we must call it on the class there.
         assert psud.Psu.get_status_master_led() == MockPsu.STATUS_LED_COLOR_GREEN
 
+    def test_first_run(self):
+        chassis = MockChassis()
+        chassis_info = psud.PsuChassisInfo(SYSLOG_IDENTIFIER, chassis)
+
+        chassis_info.total_supplied_power = 0.0
+        chassis_info.total_consumed_power = 350.0
+        chassis_info.master_status_good = False
+        ret = chassis_info.update_master_status()
+        assert ret == True
+        assert psud.Psu.get_status_master_led() == MockPsu.STATUS_LED_COLOR_RED
+
+        chassis_info.total_supplied_power = 510.0
+        chassis_info.total_consumed_power = 350.0
+        chassis_info.master_status_good = True
+        ret = chassis_info.update_master_status()
+        assert ret == True
+        assert psud.Psu.get_status_master_led() == MockPsu.STATUS_LED_COLOR_GREEN
+
     def test_get_psu_key(self):
         assert psud.get_psu_key(0) == psud.PSU_INFO_KEY_TEMPLATE.format(0)
         assert psud.get_psu_key(1) == psud.PSU_INFO_KEY_TEMPLATE.format(1)