Address some review comments; Add watchdog_base

Author: jleveque

sonic_platform_base/chassis_base.py

@@ -13,22 +13,30 @@
     raise ImportError(str(e) + " - required module not found")
 
 
+# NOTE: This class inherits the metaclass 'abc.ABCMeta' from DeviceBase
 class ChassisBase(device_base.DeviceBase):
     """
     Abstract base class for interfacing with a platform chassis
     """
 
-    __metaclass__ = abc.ABCMeta
-
     # Possible reboot causes
-    REBOOT_CAUSE_POWER_LOSS = "power_loss" 
+    REBOOT_CAUSE_POWER_LOSS = "power_loss"
     REBOOT_CAUSE_THERMAL_OVERLOAD = "thermal_overload"
     REBOOT_CAUSE_INSUFFICIENT_FAN = "insufficient_fan"
     REBOOT_CAUSE_WATCHDOG = "watchdog"
     REBOOT_CAUSE_SOFTWARE = "software"
 
-    # List of all fans available on the chassis
-    fan_list = []
+
+    # List of FanBase-derived objects representing all fans
+    # available on the chassis
+    _fan_list = []
+
+    # List of PsuBase-derived objects representing all power supply units
+    # available on the chassis
+    _psu_list = []
+
+    # Object derived from WatchdogBase for interacting with hardware watchdog
+    _watchdog = None
 
     @abc.abstractmethod
     def get_base_mac(self):
@@ -39,7 +47,7 @@ def get_base_mac(self):
             A string containing the MAC address in the format
             'XX:XX:XX:XX:XX:XX'
         """
-        return None 
+        return None
 
     @abc.abstractmethod
     def get_reboot_cause(self):
@@ -52,14 +60,18 @@ def get_reboot_cause(self):
         """
         return REBOOT_CAUSE_SOFTWARE
 
+    ##############################################
+    # Fan module methods
+    ##############################################
+
     def get_num_fans(self):
         """
         Retrieves the number of fan modules available on this chassis
 
         Returns:
             An integer, the number of fan modules available on this chassis
         """
-        return len(self.fan_list)
+        return len(self._fan_list)
 
     def get_all_fans(self):
         """
@@ -69,7 +81,7 @@ def get_all_fans(self):
             A list of objects derived from FanBase representing all fan
             modules available on this chassis
         """
-        return self.fan_list
+        return self._fan_list
 
     def get_fan(self, index):
         """
@@ -86,9 +98,65 @@ def get_fan(self, index):
         fan = None
 
         try:
-            fan = self.fan_list[index]
+            fan = self._fan_list[index]
         except IndexError:
             sys.stderr.write("Fan index {} out of range (0-{})\n".format(
-                             index, len(self.fan_list)-1))
+                             index, len(self._fan_list)-1))
 
         return fan
+
+    ##############################################
+    # PSU module methods
+    ##############################################
+
+    def get_num_psus(self):
+        """
+        Retrieves the number of power supply units available on this chassis
+
+        Returns:
+            An integer, the number of power supply units available on this
+            chassis
+        """
+        return len(self._psu_list)
+
+    def get_all_psus(self):
+        """
+        Retrieves all power supply units available on this chassis
+
+        Returns:
+            A list of objects derived from PsuBase representing all power
+            supply units available on this chassis
+        """
+        return self._psu_list
+
+    def get_fan(self, index):
+        """
+        Retrieves power supply unit represented by (1-based) index <index>
+
+        Args:
+            index: An integer, the index (1-based) of the power supply unit to
+            retrieve
+
+        Returns:
+            An object dervied from PsuBase representing the specified power
+            supply unit
+        """
+        psu = None
+
+        try:
+            psu = self._psu_list[index]
+        except IndexError:
+            sys.stderr.write("PSU index {} out of range (0-{})\n".format(
+                             index, len(self._psu_list)-1))
+
+        return psu
+
+    def get_watchdog(self):
+        """
+        Retreives hardware watchdog module on this chassis
+
+        Returns:
+            An object derived from WatchdogBase representing the hardware
+            watchdog module
+        """
+        return _watchdog

sonic_platform_base/device_base.py

@@ -7,18 +7,20 @@
 
 try:
     import abc
+    import six
 except ImportError as e:
     raise ImportError(str(e) + " - required module not found")
 
 
+# NOTE: Using 'six' module here to ensure consistent abc metaclass behavior
+# with both Python 2.x and Python 3.x
+@six.add_metaclass(abc.ABCMeta)
 class DeviceBase(object):
     """
     Abstract base class for interfacing with a generic type of platform
     peripheral device
     """
 
-    __metaclass__ = abc.ABCMeta
-
     @abc.abstractmethod
     def get_presence(self):
         """
@@ -48,7 +50,7 @@ def get_serial(self):
             string: Serial number of device
         """
         return None
-    
+
     @abc.abstractmethod
     def get_status(self):
         """

sonic_platform_base/fan_base.py

@@ -12,12 +12,12 @@
     raise ImportError(str(e) + " - required module not found")
 
 
+# NOTE: This class inherits the metaclass 'abc.ABCMeta' from DeviceBase
 class FanBase(device_base.DeviceBase):
     """
     Abstract base class for interfacing with a fan module
     """
-    __metaclass__ = abc.ABCMeta
-    
+
     # Possible fan directions
     FAN_DIRECTION_INTAKE = "intake"
     FAN_DIRECTION_EXHAUST = "exhaust"

sonic_platform_base/platform_base.py

@@ -10,17 +10,15 @@
 from __future__ import print_function
 
 try:
-    import abc
     import sys
 except ImportError as e:
     raise ImportError(str(e) + " - required module not found")
 
 
 class PlatformBase(object):
 
-    __metaclass__ = abc.ABCMeta
-
-    # List of all chassis available on the platform
+    # List of ChassisBase-derived objects representing all chassis available
+    # on the platform
     chassis_list = []
 
     def get_num_chassis(self):

sonic_platform_base/psu_base.py

@@ -11,12 +11,11 @@
 except ImportError as e:
     raise ImportError(str(e) + " - required module not found")
 
-
+# NOTE: This class inherits the metaclass 'abc.ABCMeta' from DeviceBase
 class PsuBase(device_base.DeviceBase):
     """
     Abstract base class for interfacing with a power supply unit
     """
-    __metaclass__ = abc.ABCMeta
 
     # Possible fan directions
     FAN_DIRECTION_INTAKE = "intake"

sonic_platform_base/watchdog_base.py

@@ -0,0 +1,58 @@
+#
+# watchdog_base.py
+#
+# Abstract base class for implementing a platform-specific class with which
+# to interact with a hardware watchdog module in SONiC
+#
+
+try:
+    import abc
+    from . import device_base
+except ImportError as e:
+    raise ImportError(str(e) + " - required module not found")
+
+
+# NOTE: This class inherits the metaclass 'abc.ABCMeta' from DeviceBase
+class WatchdogBase(device_base.DeviceBase):
+    """
+    Abstract base class for interfacing with a hardware watchdog module
+    """
+
+    # Possible fan directions
+    FAN_DIRECTION_INTAKE = "intake"
+    FAN_DIRECTION_EXHAUST = "exhaust"
+
+    @abc.abstractmethod
+    def arm(self, seconds):
+        """
+        Arm the hardware watchdog with a timeout of <seconds> seconds
+
+        Returns:
+            A boolean, True if watchdog is armed successfully, False if not
+        """
+        return None
+
+    @abc.abstractmethod
+    def disarm(self):
+        """
+        Disarm the hardware watchdog
+
+        Returns:
+            A boolean, True if watchdog is disarmed successfully, False if not
+        """
+        return 0
+
+    @abc.abstractmethod
+    def is_armed(self):
+        """
+        Retrieves the armed state of the hardware watchdog and if armed, the
+        number of seconds remaining on the watchdog timer
+
+        Returns:
+            A tuple of the form (bool, int). If the watchdog is armed, the
+            first value will be 'true' and the second value will be the
+            number of seconds remaining on the watchdog timer. If the watchdog
+            is disarmed, the first value will be 'false' and the integer
+            returned as the second value should be ignored.
+        """
+        return (false, 0)