Add sonic_psu module along with initial psu_base.py base class for pl…

…ugins (sonic-net#116)

setup.py

@@ -11,7 +11,7 @@
     url='https://github.com/Azure/sonic-utilities',
     maintainer='Joe LeVeque',
     maintainer_email='[email protected]',
-    packages=['config', 'sfputil', 'show', 'sonic_eeprom', 'sonic_sfp', "sonic_installer"],
+    packages=['config', 'sfputil', 'show', 'sonic_eeprom', 'sonic_installer', 'sonic_psu', 'sonic_sfp'],
     package_data={
         'show': ['aliases.ini']
     },

sonic_psu/psu_base.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python
+#
+# psu_base.py
+#
+# Abstract base class for implementing platform-specific
+#  PSU control functionality for SONiC
+#
+
+try:
+    import abc
+except ImportError, e:
+    raise ImportError (str(e) + " - required module not found")
+
+class PsuBase(object):
+    __metaclass__ = abc.ABCMeta
+
+    @abc.abstractmethod
+    def get_psu_status(self, index):
+        """
+        Retrieves the oprational status of power supply unit (PSU) defined
+                by index <index>
+
+        :param index: An integer, index of the PSU of which to query status
+        :return: Boolean, True if PSU is operating properly, False if PSU is faulty
+        """
+        return False