Added execute_cmds_via_open_connection

* There are use cases where rather than SSH to a remote server
  to execute cmds, the connection to the remote server is already
  open, so use that connection to execute the commands.

  USE CASE (example):
  Execute cmds on/from proxy server: conn = connect_to_proxy(), and
  then use that connection to execute commands.)

* Updated to better check if connection provided could be a connection
  Raise execption if it is not a pexpect.spawn object.

Change-Id: Ie01aa891ecbfe76a1231cd0714ce5511bc4d05cc

cloudcafe/networking/networks/common/proxy_mgr/ssh_util.py

@@ -18,6 +18,12 @@ class MissingCredentials(SshUnableToConnect):
     MSG = 'Missing credentials to connect to: {ip} (Type: {t_type})'
 
 
+class ConnectionNotFound(Exception):
+    def __str__(self):
+        return ('No open pexpect connection was provided. Was not type '
+                'pexpect.spawn')
+
+
 class SshResponse(object):
     str_concat = '{0!s}\n{1!s}'
 
@@ -372,6 +378,32 @@ class SshMixin(object):
         self.last_response = response_obj
         return response_obj
 
+    def execute_cmds_via_open_connection(
+            self, connection, cmds, response_obj=None, close_conn=False):
+        """
+        Execute the list of commands on the open connection
+
+        @param connection: Open pexpect connection
+        @param cmds: list of commands to execute
+        @param response_obj: The SSH Response object; instantiated if !provided
+        @param close_conn: (Boolean), Close the connection when done?
+        @return: Populated response object
+        """
+
+        if not isinstance(connection, pexpect.spawn):
+            raise ConnectionNotFound()
+
+        if response_obj is None:
+            response_obj = SshResponse()
+            response_obj.connection = connection
+
+        args = {'response_obj': response_obj, 'cmds': cmds}
+
+        response_obj = self._cmds_via_open_connection(**args)
+        if close_conn:
+            self.close_connections(response_obj)
+        return response_obj
+
     def _cmds_via_open_connection(self, response_obj, cmds):
         """
         SSH from the local host using pexpect.