Source code for can.util

#!/usr/bin/env python3
Utilities and configuration file parsing.
from __future__ import absolute_import

import can
from can.interfaces import VALID_INTERFACES

    from configparser import ConfigParser
except ImportError:
    from ConfigParser import SafeConfigParser as ConfigParser
import os
import os.path
import sys
import platform
import re
import logging

log = logging.getLogger('can.util')


CONFIG_FILES = ['~/can.conf']

if platform.system() == "Linux":
elif platform.system() == "Windows" or platform.python_implementation() == "IronPython":
            os.path.join(os.getenv('APPDATA', ''), 'can.ini')

[docs]def load_file_config(path=None): """ Loads configuration from file with following content:: [default] interface = socketcan channel = can0 :param path: path to config file. If not specified, several sensible default locations are tried depending on platform. """ config = ConfigParser() if path is None:[os.path.expanduser(path) for path in CONFIG_FILES]) else: if not config.has_section('default'): return {} return dict( (key, val) for key, val in config.items('default') )
[docs]def load_environment_config(): """ Loads config dict from environmental variables (if set): * CAN_INTERFACE * CAN_CHANNEL * CAN_BITRATE """ mapper = { 'interface': 'CAN_INTERFACE', 'channel': 'CAN_CHANNEL', 'bitrate': 'CAN_BITRATE', } return dict( (key, os.environ.get(val)) for key, val in mapper.items() if val in os.environ )
[docs]def load_config(path=None, config=None): """ Returns a dict with configuration details which is loaded from (in this order): - config - can.rc - Environment variables CAN_INTERFACE, CAN_CHANNEL, CAN_BITRATE - Config files ``/etc/can.conf`` or ``~/.can`` or ``~/.canrc`` where the latter may add or replace values of the former. Interface can be any of the strings from ``can.VALID_INTERFACES`` for example: kvaser, socketcan, pcan, usb2can, ixxat, nican, virtual. .. note:: If you pass ``"socketcan"`` this automatically selects between the native and ctypes version. :param path: Optional path to config file. :param config: A dict which may set the 'interface', and/or the 'channel', or neither. :return: A config dictionary that should contain 'interface' & 'channel':: { 'interface': 'python-can backend interface to use', 'channel': 'default channel to use', } Note ``None`` will be used if all the options are exhausted without finding a value. """ if config is None: config = {} system_config = {} configs = [ config, can.rc, load_environment_config, lambda: load_file_config(path) ] # Slightly complex here to only search for the file config if required for cfg in configs: if callable(cfg): cfg = cfg() for key in cfg: if key not in system_config and cfg[key] is not None: system_config[key] = cfg[key] # substitute None for all values not found for key in REQUIRED_KEYS: if key not in system_config: system_config[key] = None if system_config['interface'] == 'socketcan': system_config['interface'] = choose_socketcan_implementation() if system_config['interface'] not in VALID_INTERFACES: raise NotImplementedError('Invalid CAN Bus Type - {}'.format(can.rc['interface'])) if 'bitrate' in system_config: system_config['bitrate'] = int(system_config['bitrate']) can.log.debug("can config: {}".format(system_config)) return system_config
[docs]def choose_socketcan_implementation(): """Set the best version of SocketCAN for this system. :param config: The can.rc configuration dictionary :raises Exception: If the system doesn't support SocketCAN """ # Check OS: SocketCAN is available only under Linux if not sys.platform.startswith('linux'): msg = 'SocketCAN not available under {}'.format( sys.platform) raise Exception(msg) else: # Check release: SocketCAN was added to Linux 2.6.25 rel_string = platform.release() m = re.match(r'\d+\.\d+\.\d', rel_string) if m is None: msg = 'Bad linux release {}'.format(rel_string) raise Exception(msg) rel_num = [int(i) for i in rel_string[:m.end()].split('.')] if (rel_num >= [2, 6, 25]): # Check Python version: SocketCAN was added in 3.3 return 'socketcan_native' if sys.version_info >= (3, 3) else 'socketcan_ctypes' else: msg = 'SocketCAN not available under Linux {}'.format( rel_string) raise Exception(msg)
[docs]def set_logging_level(level_name=None): """Set the logging level for the "can" logger. Expects one of: 'critical', 'error', 'warning', 'info', 'debug', 'subdebug' """ can_logger = logging.getLogger('can') try: can_logger.setLevel(getattr(logging, level_name.upper())) except AttributeError: can_logger.setLevel(logging.DEBUG) log.debug("Logging set to {}".format(level_name))
if __name__ == "__main__": print("Searching for configuration named:") print("\n".join(CONFIG_FILES)) print("Settings:") print(load_config())