openstack日志模块

zsy001

　　一、简单的python日志模块介绍
　　http://www.iyunv.com/tuzkee/p/3974193.html
　　http://blog.iyunv.com/jgood/article/details/4340740
　　
　　二、日志的配置
　　openstack服务程序在启动的时候都会对日志系统进行设置，这里以nova-api为例，在它的的启动代码里：
　　nova/cmd/api.py



def main():
config.parse_args(sys.argv)
logging.setup("nova")
...
　　由于在/etc/init.d/openstack-nova-api控制脚本里已经传入参数，所以sys.argv为['/usr/bin/nova-api', '--logfile', '/var/log/nova/api.log']，即在配置参数里面设置了日志系统的文件记录地址。接着看日志的设置代码如下:
　　nova/openstack/common/log.py



def setup(product_name):
if CONF.log_config:
_load_log_config(CONF.log_config)
else:
_setup_logging_from_conf()
sys.excepthook = _create_logging_excepthook(product_name)

def _setup_logging_from_conf():
"""
获取根logger，此后创建的所有logger都继承了它的配置，所以此后创建的logger基本不需要配置就可以直接使用
"""
log_root = getLogger(None).logger   
for handler in log_root.handlers:
log_root.removeHandler(handler)
if CONF.use_syslog:
facility = _find_facility_from_conf()
syslog = logging.handlers.SysLogHandler(address='/dev/log',
facility=facility)
log_root.addHandler(syslog)
"""设置日志输出位置"""
logpath = _get_log_file_path()#获取刚刚设置的日志文件路径
if logpath:
filelog = logging.handlers.WatchedFileHandler(logpath)
log_root.addHandler(filelog)
if CONF.use_stderr:
streamlog = ColorHandler()
log_root.addHandler(streamlog)
elif not CONF.log_file:
streamlog = logging.StreamHandler(sys.stdout)
log_root.addHandler(streamlog)
if CONF.publish_errors:
handler = importutils.import_object(
"nova.openstack.common.log_handler.PublishErrorsHandler",
logging.ERROR)
log_root.addHandler(handler)
"""设置日志格式"""
datefmt = CONF.log_date_format
for handler in log_root.handlers:
if CONF.log_format:
handler.setFormatter(logging.Formatter(fmt=CONF.log_format,
datefmt=datefmt))
log_root.info('Deprecated: log_format is now deprecated and will '
'be removed in the next release')
else:
handler.setFormatter(ContextFormatter(datefmt=datefmt))
"""设置日志级别"""
if CONF.debug:
log_root.setLevel(logging.DEBUG)
elif CONF.verbose:
log_root.setLevel(logging.INFO)
else:
log_root.setLevel(logging.WARNING)
for pair in CONF.default_log_levels:
mod, _sep, level_name = pair.partition('=')
level = logging.getLevelName(level_name)
logger = logging.getLogger(mod)
logger.setLevel(level)
　　
　　三、日志的使用
　　首先导入并获取logger



from nova.openstack.common import log as logging
LOG = logging.getLogger(__name__)
　　其中的LOG是经过openstack定制的logger，可见如下代码：



def getLogger(name='unknown', version='unknown'):
if name not in _loggers:
_loggers[name] = ContextAdapter(logging.getLogger(name),
name,
version)
return _loggers[name]
class ContextAdapter(BaseLoggerAdapter):
warn = logging.LoggerAdapter.warning
def __init__(self, logger, project_name, version_string):
self.logger = logger
self.project = project_name
self.version = version_string
　　接着就可以使用logger了，例如：



LOG.error(xxx)