为什么我在OS X上使用Python的SysLogHandler在syslog消息中得到一个虚假的']'字符？

使用OS X 10.10.4上的Python 3.5,我]在输出系统日志消息中得到虚假字符.这可以通过以下示例程序看到:

#!/usr/bin/env python3

import logging
import logging.handlers

logger = logging.getLogger('test')

syslog_handler = logging.handlers.SysLogHandler(address='/var/run/syslog')
syslog_formatter = logging.Formatter('[{process}] {message}', )
syslog_handler.setFormatter(syslog_formatter)

logger.addHandler(syslog_handler)
logger.error("Test : ABC")

如果我运行这个,我看到syslog输出如下:

Dec 16 12:38:33 mymachinename [76399] Test]: ABC

(注意之后的虚假]角色Test).

如果我稍微更改格式化程序字符串以删除初始[字符,则附加]消失.但是,我希望这个文字字符出现在格式化的字符串中(即使它不在格式化字符串的开头,我也有同样的问题).

为什么会]出现这种虚假现象,我该如何避免呢？

OS X asl.conf是配置日志记录的地方,如下所示.我没有修改默认值:

##
# configuration file for syslogd and aslmanager
##

# authpriv messages are root/admin readable
? [= Facility authpriv] access 0 80

# remoteauth critical, alert, and emergency messages are root/admin readable
? [= Facility remoteauth] [<= Level critical] access 0 80

# broadcast emergency messages
? [= Level emergency] broadcast

# save kernel [PID 0] and launchd [PID 1] messages
? [<= PID 1] store

# ignore "internal" facility
? [= Facility internal] ignore

# save everything from emergency to notice
? [<= Level notice] store

# Rules for /var/log/system.log
> system.log mode=0640 format=bsd rotate=seq compress file_max=5M all_max=50M
? [= Sender kernel] file system.log
? [<= Level notice] file system.log
? [= Facility auth] [<= Level info] file system.log
? [= Facility authpriv] [<= Level info] file system.log
? [= Facility user] [<= Level debug] file system.log

# Facility com.apple.alf.logging gets saved in appfirewall.log
? [= Facility com.apple.alf.logging] file appfirewall.log file_max=5M all_max=

我在Ubuntu 10.04上没有看到同样的问题,因此它似乎是特定于OS X的.