Document the code layout for the pool manager

Change-Id: I8d30dae0e7acc68c23aca832056cce5c351845e6

doc/pool_mgm/code.rst

@@ -0,0 +1,130 @@
+Code Walkthrough
+================
+
+Here we'll highlight some of the more important code aspects.
+
+Server Class
+------------
+.. py:module:: libra.mgm.mgm
+
+.. py:class:: Server(logger, args)
+
+   This class is the main server activity once it has started in either
+   daemon on non-daemon mode.
+
+   :param logger: An instance of :py:class:`logging.logger`
+   :param args: An instance of :py:class:`libra.common.options.Options`
+
+   .. py:method:: main()
+
+      Sets the signal handler and then called :py:meth:`check_nodes`
+
+   .. py:method:: check_nodes()
+
+      Runs a check to see if new nodes are needed.  Called once by
+      :py:meth:`main` at start and then called by the scheduler.
+      It also restarts the scheduler at the end of execution
+
+   .. py:method:: reset_scheduler()
+
+      Uses :py:class:`threading.Timer` to set the next scheduled execution of
+      :py:meth:`check_nodes`
+
+   .. py:method:: build_nodes(count, api)
+
+       Builds the required number of nodes determined by
+       :py:meth:`check_nodes`.
+
+       :param count: The number of nodes to build
+       :param api: A driver derived from the :py:class:`MgmDriver` parent class
+
+   .. py:method:: exit_handler(signum, frame)
+
+      The signal handler function.  Clears the signal handler and calls
+      :py:meth:`shutdown`
+
+      :param signum: The signal number
+      :param frame: The stack frame
+
+   .. py:method:: shutdown(error)
+
+      Causes the application to exit
+
+      :param error: set to True if an error caused shutdown
+      :type error: boolean
+
+Node Class
+----------
+
+.. py:module:: libra.mgm.node
+
+.. py:class:: Node(username, password, tenant, auth_url, region, keyname, secgroup, image, node_type)
+
+   This class uses :py:class:`novaclient.client` to manipulate Nova nodes
+
+   :param username: The Nova username
+   :param password: The Nova password
+   :param tenant: The Nova tenant
+   :param auth_url: The Nova authentication URL
+   :param region: The Nova region
+   :param keyaname: The Nova key name for new nodes
+   :param secgroup: The Nova security group for new nodes
+   :param image: The Nova image ID for new nodes
+   :param node_type: The flavor ID for new nodes
+
+   .. py:method:: build()
+
+      Creates a new Nova node and tests that it is running.  It will poll
+      every 3 seconds for 2 minutes to check if the node is running.
+
+      :return: True and status dictionary for success, False and error for fail
+
+MgmDriver Class
+---------------
+
+.. py:module:: libra.mgm.drivers.base
+
+.. py:class:: MgmDriver
+
+   The defines the API for interacting with various API servers. Drivers for
+   these API servers should inherit from this class and implement the relevant
+   API methods that it can support.
+   `This is an abstract class and is not meant to be instantiated directly.`
+
+   .. py:method:: get_free_count()
+
+      Gets the number of free nodes.  This is used to calculate if more nodes
+      are needed
+
+      :return: the number of free nodes
+
+   .. py:method:: add_node(name, address)
+
+      Adds the node details for a new device to the API server.
+
+      :param name: the new name for the node
+      :param address: the new public IP address for the node
+      :return: True or False and the JSON response (if any)
+
+   .. py:method:: is_online()
+
+      Check to see if the driver has access to a valid API server
+
+      :return: True or False
+
+   .. py:method:: get_url()
+
+      Gets the URL for the current API server
+
+      :return: the URL for the current API server
+
+Known Drivers Dictionary
+------------------------
+
+.. py:data:: known_drivers
+
+   This is the dictionary that maps values for the :option:`--driver` option
+   to a class implementing the driver :py:class:`~MgmDriver` API
+   for that API server. After implementing a new driver class, you simply add
+   a new entry to this dictionary to plug in the new driver.
+

doc/pool_mgm/index.rst

@@ -5,3 +5,4 @@ Libra Node Pool Manager
    :maxdepth: 2
 
    about
+   code