"""Utility functions for FAUCET."""
# Copyright (C) 2015 Brad Cowie, Christopher Lorier and Joe Stringer.
# Copyright (C) 2015 Research and Education Advanced Network New Zealand Ltd.
# Copyright (C) 2015--2019 The Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
from logging.handlers import WatchedFileHandler
import os
import signal
import sys
from functools import wraps
[docs]def kill_on_exception(logname):
"""decorator to ensure functions will kill ryu when an unhandled exception
occurs"""
def _koe(func):
@wraps(func)
def __koe(*args, **kwargs):
try:
func(*args, **kwargs)
except:
logging.getLogger(logname).exception(
'Unhandled exception, killing RYU')
logging.shutdown()
os.kill(os.getpid(), signal.SIGTERM)
return __koe
return _koe
[docs]def utf8_decode(msg_str):
"""Gracefully decode a possibly UTF-8 string."""
return msg_str.decode('utf-8', errors='replace')
[docs]def get_sys_prefix():
"""Returns an additional prefix for log and configuration files when used in
a virtual environment"""
# Find the appropriate prefix for config and log file default locations
# in case Faucet is run in a virtual environment. virtualenv marks the
# original path in sys.real_prefix. If this value exists, and is
# different from sys.prefix, then we are most likely running in a
# virtualenv. Also check for Py3.3+ pyvenv.
sysprefix = ''
if (getattr(sys, 'real_prefix', sys.prefix) != sys.prefix or
getattr(sys, 'base_prefix', sys.prefix) != sys.prefix):
sysprefix = sys.prefix
return sysprefix
_PREFIX = get_sys_prefix()
# To specify a boolean-only setting, set the default value to a bool type.
DEFAULTS = {
'FAUCET_CONFIG': ''.join((
_PREFIX,
'/etc/faucet/faucet.yaml',
':',
_PREFIX,
'/etc/ryu/faucet/faucet.yaml')),
'FAUCET_CONFIG_STAT_RELOAD': False,
'FAUCET_CONFIG_AUTO_REVERT': False,
'FAUCET_LOG_LEVEL': 'INFO',
'FAUCET_LOG': _PREFIX + '/var/log/faucet/faucet.log',
'FAUCET_EVENT_SOCK': '', # Special-case, see get_setting().
'FAUCET_EVENT_SOCK_HEARTBEAT': 0, # Special-case, see get_setting().
'FAUCET_EXCEPTION_LOG': _PREFIX + '/var/log/faucet/faucet_exception.log',
'FAUCET_PROMETHEUS_PORT': '9302',
'FAUCET_PROMETHEUS_ADDR': '0.0.0.0',
'GAUGE_CONFIG': ''.join((
_PREFIX,
'/etc/faucet/gauge.yaml',
':',
_PREFIX,
'/etc/ryu/faucet/gauge.yaml')),
'GAUGE_CONFIG_STAT_RELOAD': False,
'GAUGE_LOG_LEVEL': 'INFO',
'GAUGE_PROMETHEUS_ADDR': '0.0.0.0',
'GAUGE_EXCEPTION_LOG': _PREFIX + '/var/log/faucet/gauge_exception.log',
'GAUGE_LOG': _PREFIX + '/var/log/faucet/gauge.log'
}
def _cast_bool(value):
"""Return True if value is a non-zero int."""
try:
return int(value) != 0
except ValueError:
return False
[docs]def get_setting(name, path_eval=False):
"""Returns value of specified configuration setting."""
default_value = DEFAULTS[name]
result = os.getenv(name, default_value)
# split on ':' and find the first suitable path
if (path_eval and
isinstance(result, str) and
isinstance(default_value, str) and not
isinstance(default_value, bool)):
locations = result.split(":")
result = None
for loc in locations:
if os.path.isfile(loc):
result = loc
break
if result is None:
result = locations[0]
# Check for setting that expects a boolean result.
if isinstance(default_value, bool):
return _cast_bool(result)
# Special default for FAUCET_EVENT_SOCK.
if name == 'FAUCET_EVENT_SOCK':
if result == '0':
return ''
if _cast_bool(result):
return _PREFIX + '/var/run/faucet/faucet.sock'
if name == 'FAUCET_EVENT_SOCK_HEARTBEAT':
if result == '0':
return 0
return result
[docs]def get_logger(logname, logfile, loglevel, propagate):
"""Create and return a logger object."""
stream_handlers = {
'STDOUT': sys.stdout,
'STDERR': sys.stderr,
}
try:
if logfile in stream_handlers:
logger_handler = logging.StreamHandler(stream_handlers[logfile])
else:
logger_handler = WatchedFileHandler(logfile)
except (PermissionError, FileNotFoundError) as err: # pytype: disable=name-error
print(err)
sys.exit(-1)
logger = logging.getLogger(logname)
log_fmt = '%(asctime)s %(name)-6s %(levelname)-8s %(message)s'
logger_handler.setFormatter(
logging.Formatter(log_fmt, '%b %d %H:%M:%S'))
logger.addHandler(logger_handler)
logger.propagate = propagate
logger.setLevel(loglevel)
return logger
[docs]def close_logger(logger):
"""Close all handlers on logger object."""
if logger is None:
return
for handler in list(logger.handlers):
handler.close()
logger.removeHandler(handler)
[docs]def dpid_log(dpid):
"""Log a DP ID as hex/decimal."""
return 'DPID %u (0x%x)' % (dpid, dpid)
[docs]def stat_config_files(config_hashes):
"""Return dict of a subset of stat attributes on config files."""
config_files_stats = {}
for config_file in list(config_hashes.keys()):
try:
config_file_stat = os.stat(config_file)
except OSError:
continue
config_files_stats[config_file] = (
config_file_stat.st_size,
config_file_stat.st_mtime,
config_file_stat.st_ctime)
return config_files_stats