openstack日志模块

一、简单的python日志模块介绍

http://www.cnblogs.com/tuzkee/p/3974193.html

http://blog.csdn.net/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)

巴特西

openstack日志模块

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