Vland/drivers/common.py

#! /usr/bin/python

#  Copyright 2014-2015 Linaro Limited
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.

import time
import logging

from errors import InputError, PExpectError

class SwitchErrors:
    """ Error logging and statistics class """

    def __init__(self):
        self.errors_in = 0
        self.errors_out = 0

    def __repr__(self):
        return "<SwitchErrors: errors_in: %d, errors_out: %d>" % (self.errors_in, self.errors_out)

    # For now, just count the error. Later on we might add stats and
    # analysis
    def log_error_in(self, text):
        self.errors_in += 1

    # For now, just count the error. Later on we might add stats and
    # analysis
    def log_error_out(self, text):
        self.errors_out += 1

class SwitchDriver(object):

    connection = None
    hostname = ""
    serial_number = ''

    _allowed_port_modes = [ "trunk", "access" ]
    _ports = []
    _port_modes = {}
    _port_numbers = {}
    _prompt_name = ''
    _username = ''
    _password = ''
    _enable_password = ''
    _systemdata = []

    def __init__ (self, switch_hostname, debug):

        if debug:
            # Configure logging for pexpect output if we have debug
            # enabled

            # get the logger
            self.logger = logging.getLogger(switch_hostname)

            # give the logger the methods required by pexpect
            self.logger.write = self._log_write
            self.logger.flush = self._log_do_nothing

        else:
            self.logger = None

        self.hostname = switch_hostname

    # Connect to the switch and log in
    def switch_connect(self, username, password, enablepassword):
        self._username = username
        self._password = password
        self._enable_password = enablepassword
        self._switch_connect()

    # Log out of the switch and drop the connection and all state
    def switch_disconnect(self):
        self._logout()
        logging.debug("Closing connection to %s", self.hostname)
        self._ports = []
        self._port_modes.clear()
        self._port_numbers.clear()
        self._prompt_name = ''
        self._systemdata = []
        del(self)

    def dump_list(self, data):
        i = 0
        for line in data:
            print "%d: \"%s\"" % (i, line)
            i += 1

    def _delay(self):
        time.sleep(0.5)

    # List the capabilities of the switch (and driver) - some things
    # make no sense to abstract. Returns a dict of strings, each one
    # describing an extra feature that that higher levels may care
    # about
    def switch_get_capabilities(self):
        return self._capabilities

    # List the names of all the ports on the switch
    def switch_get_port_names(self):
        return self._ports

    def _is_port_name_valid(self, name):
        for port in self._ports:
            if name == port:
                return True
        return False

    def _is_port_mode_valid(self, mode):
        for allowed in self._allowed_port_modes:
            if allowed == mode:
                return True
        return False

    # Try to look up a port mode in our cache. If not there, go ask
    # the switch and cache the result
    def port_get_mode(self, port):
        if not self._is_port_name_valid(port):
            raise InputError("Port name %s not recognised" % port)
        if port in self._port_modes:
            logging.debug("port_get_mode: returning mode %s from cache for port %s", self._port_modes[port], port)
            return self._port_modes[port]
        else:
            mode = self._port_get_mode(port)
            self._port_modes[port] = mode
            logging.debug("port_get_mode: found mode %s for port %s, adding to cache", self._port_modes[port], port)
            return mode

    def port_map_name_to_number(self, port_name):
        if not self._is_port_name_valid(port_name):
            raise InputError("Port name %s not recognised" % port_name)
        logging.debug("port_map_name_to_number: returning %d for port_name %s", self._port_numbers[port_name], port_name)
        return self._port_numbers[port_name]

    # Wrappers to adapt logging for pexpect when we've configured on a
    # switch.
    # This will be the method called by the pexpect object to write a
    # log message
    def _log_write(self, *args, **kwargs):
        # ignore other parameters, pexpect only uses one arg
        content = args[0]

        if content in [' ', '', '\n', '\r', '\r\n']:
            return # don't log empty lines

        # Split the output into multiple lines so we get a
        # well-formatted logfile
        for line in content.split('\r\n'):
            logging.info(line)

    # This is the flush method for pexpect
    def _log_do_nothing(self):
        pass