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"""
Library for configuring python logging to standard ROS locations (e.g. ROS_LOG_DIR).
"""

import os
import sys
import time
import logging
import logging.config

import rospkg
from rospkg.environment import ROS_LOG_DIR

class LoggingException: pass

def configure_logging(logname, level=logging.INFO, filename=None, env=None):
    """
    Configure Python logging package to send log files to ROS-specific log directory
    :param logname str: name of logger, ``str``
    :param filename: filename to log to. If not set, a log filename
        will be generated using logname, ``str``
    :param env: override os.environ dictionary, ``dict``
    :returns: log file name, ``str``
    :raises: :exc:`LoggingException` If logging cannot be configured as specified
    """
    if env is None:
        env = os.environ

    logname = logname or 'unknown'
    log_dir = rospkg.get_log_dir(env=env)
    
    # if filename is not explicitly provided, generate one using logname
    if not filename:
        log_filename = os.path.join(log_dir, '%s-%s.log'%(logname, os.getpid()))
    else:
        log_filename = os.path.join(log_dir, filename)

    logfile_dir = os.path.dirname(log_filename)
    if not os.path.exists(logfile_dir):
        try:
            makedirs_with_parent_perms(logfile_dir)
        except OSError:
            # cannot print to screen because command-line tools with output use this
            sys.stderr.write("WARNING: cannot create log directory [%s]. Please set %s to a writable location.\n"%(logfile_dir, ROS_LOG_DIR))
            return None
    elif os.path.isfile(logfile_dir):
        raise LoggingException("Cannot save log files: file [%s] is in the way"%logfile_dir)

    if 'ROS_PYTHON_LOG_CONFIG_FILE' in os.environ:
        config_file = os.environ['ROS_PYTHON_LOG_CONFIG_FILE']
    else:
        # search for logging config file in /etc/.  If it's not there,
        # look for it package-relative.
        fname = 'python_logging.conf'
        rosgraph_d = rospkg.RosPack().get_path('rosgraph')
        for f in [os.path.join(rospkg.get_ros_home(), 'config', fname),
                  '/etc/ros/%s'%(fname),
                  os.path.join(rosgraph_d, 'conf', fname)]:
            if os.path.isfile(f):
                config_file = f
                break
        else:
            config_file = None

    if config_file is None or not os.path.isfile(config_file):
        # logging is considered soft-fail
        sys.stderr.write("WARNING: cannot load logging configuration file, logging is disabled\n")
        logging.getLogger(logname).setLevel(logging.CRITICAL)
        return log_filename
    
    # pass in log_filename as argument to pylogging.conf
    os.environ['ROS_LOG_FILENAME'] = log_filename
    # #3625: disabling_existing_loggers=False
    logging.config.fileConfig(config_file, disable_existing_loggers=False)
    return log_filename

def makedirs_with_parent_perms(p):
    """
    Create the directory using the permissions of the nearest
    (existing) parent directory. This is useful for logging, where a
    root process sometimes has to log in the user's space.
    :param p: directory to create, ``str``
    """    
    p = os.path.abspath(p)
    parent = os.path.dirname(p)
    # recurse upwards, checking to make sure we haven't reached the
    # top
    if not os.path.exists(p) and p and parent != p:
        makedirs_with_parent_perms(parent)
        s = os.stat(parent)
        os.mkdir(p)

        # if perms of new dir don't match, set anew
        s2 = os.stat(p)
        if s.st_uid != s2.st_uid or s.st_gid != s2.st_gid:
            os.chown(p, s.st_uid, s.st_gid)
        if s.st_mode != s2.st_mode:
            os.chmod(p, s.st_mode)    

_logging_to_rospy_names = {
    'DEBUG': ('DEBUG', '\033[32m'),
    'INFO': ('INFO', None),
    'WARNING': ('WARN', '\033[33m'),
    'ERROR': ('ERROR', '\033[31m'),
    'CRITICAL': ('FATAL', '\033[31m')
}
_color_reset = '\033[0m'

class RosStreamHandler(logging.Handler):
    def __init__(self, colorize=True):
        super(RosStreamHandler, self).__init__()
        self._colorize = colorize
        try:
            from rospy.rostime import get_time, is_wallclock
            self._get_time = get_time
            self._is_wallclock = is_wallclock
        except ImportError:
            self._get_time = None
            self._is_wallclock = None

    def emit(self, record):
        level, color = _logging_to_rospy_names[record.levelname]
        msg = '[%s] [WallTime: %f]' % (level, time.time())
        if self._get_time is not None and not self._is_wallclock():
            msg += ' [%f]' % self._get_time()
        msg += ' %s\n' % record.getMessage()

        if record.levelno < logging.WARNING:
            self._write(sys.stdout, msg, color)
        else:
            self._write(sys.stderr, msg, color)

    def _write(self, fd, msg, color):
        if self._colorize and color and fd.isatty():
            msg = color + msg + _color_reset
        fd.write(msg)
