Support syslog handler in logging.py

[ZQyou]

We use splunk + syslog for performance check and visualization instead of using special log server. Adding syslog handler in logging.py seems trivial and I have done this on my side:

def _create_syslog_handler(handler_config):
    return logging.handlers.SysLogHandler(address = '/dev/log')

def _create_stream_handler(handler_config):
    stream = handler_config.get('name', 'stdout')
    if stream == 'stdout':
            hdlr = _create_file_handler(handler_config)
        elif handler_type == 'filelog':
            hdlr = _create_filelog_handler(handler_config)
        elif handler_type == 'syslog':
            hdlr = _create_syslog_handler(handler_config)
        elif handler_type == 'stream':
            hdlr = _create_stream_handler(handler_config)
...

[vkarak]

Thanks @ZQyou, I was thinking the same thing these days, cos several sites use syslog and some elastic search to pipe the syslog into. Would you mind doing a PR for that, since you already have it running?

[ZQyou]

Sure, I will work on that.