kytos / of_stats

"""Manage link speeds when OF spec is not enough."""

import json

from os.path import dirname

from pathlib import Path

class UserSpeed:

    """User-defined interface speeds.

    In case there is no matching speed in OF spec or the speed is not correctly

    detected.

    """

    _FILE = Path(dirname(__file__)) / 'user_speed.json'

    def __init__(self):

        """Load user-created file."""

        if self._FILE.exists():

            with self._FILE.open() as user_file:

                # print('UserSpeed', user_file.read())

                self._speed = json.load(user_file)

        else:

            self._speed = {}

    def get_speed(self, dpid, port=None):

        """Return speed in bits/sec or None if not defined by the user.

        Args:

            dpid (str): Switch dpid.

            port (int or str): Port number.

        """

        if not isinstance(port, str):

            port = str(port)

        speed = None

        switch = self._speed.get(dpid)

        if switch is None:

            speed = self._speed.get('default')

        else:

            if port is None or port not in switch:

                speed = switch.get('default')

            else:

                speed = switch.get(port)

        return speed