Python logging模塊無法正常輸出日志

廢話少說，先上代碼

• File：logger.conf
   
  [formatters]
  keys=default
   
  [formatter_default]
  format=%(asctime)s - %(name)s - %(levelname)s - %(message)s
  class=logging.Formatter
   
  [handlers]
  keys=console, error_file
   
  [handler_console]
  class=logging.StreamHandler
  formatter=default
  args=tuple()
   
  [handler_error_file]
  class=logging.FileHandler
  level=INFO
  formatter=default
  args=("logger.log", "a")
   
  [loggers]
  keys=root
   
  [logger_root]
  level=DEBUG
  formatter=default
  handlers=console,error_file
  

   

  File：logger.py
   
  #!/bin/env python
   
  import logging
  from logging.config import logging
   
  class Test(object):
      """docstring for Test"""
      def __init__(self):
          logging.config.fileConfig("logger.conf")
          self.logger = logging.getLogger(__name__)
   
      def test_func(self):
          self.logger.error('test_func function')
   
  class Worker(object):
      """docstring for Worker"""
      def __init__(self):
          logging.config.fileConfig("logger.conf")
          self.logger = logging.getLogger(__name__)
   
          data_logger = logging.getLogger('data')
          handler = logging.FileHandler('./data.log')
          fmt = logging.Formatter('%(asctime)s|%(message)s')
          handler.setFormatter(fmt)
          data_logger.addHandler(handler)
          data_logger.setLevel(logging.DEBUG)
          self.data_logger = data_logger
   
      def test_logger(self):
          self.data_logger.error("test_logger function")
          instance = Test()
          self.data_logger.error("test_logger output")
          instance.test_func()
   
   
  def main():
      worker = Worker()
      worker.test_logger()
   
  if __name__ == '__main__':
      main()
  

   

問題一：測試過程中，只能打印出 test_logger function一條語句

問題二：明明只在data_logger中打印出語句，但是logger的日志中也出現了相關的日志。

 

問題一解決方案：利用 python -m pdb logger.py 語句對腳本進行調試發現，在執行instance = Test()語句后，通過 print '\n'.join(['%s:%s' % item for item in self.data_logger.__dict__.items()])調試語句看到data_logger的disable屬性值由0變成了True，此時logger的對應屬性也發生了相同的變化。這種變化導致了logger對象停止記錄日志。參考python  logging模塊的相關手冊發現 “The fileConfig() function takes a default parameter, disable_existing_loggers, which defaults to True for reasons of backward compatibility. This may or may not be what you want, since it will cause any loggers existing before the fileConfig() call to be disabled unless they (or an ancestor) are explicitly named in the configuration.” 的說明，即調用fileconfig()函數會將之前存在的所有logger禁用。在python 2.7版本該fileConfig()函數添加了一個參數，logging.config.fileConfig(fname, defaults=None, disable_existing_loggers=True)，可以顯式的將disable_existing_loggers設置為FALSE來避免將原有的logger禁用。將上述代碼中的Test類中的logging.config.fileConfig函數改成logging.config.fileConfig("./logger.conf", disable_existing_loggers=0)就可以解決問題。 不過該代碼中由於位於同一程序內，可以直接用logging.getLogger(LOGGOR_NAME)函數引用同一個logger，不用再調用logging.config.fileConfig函數重新加載一遍了。

 

問題二解決方案：logger對象有個屬 性propagate，如果這個屬性為True，就會將要輸出的信息推送給該logger的所有上級logger，這些上級logger所對應的handlers就會把接收到的信息打印到關聯的日志中。logger.conf配置文件中配置了相關的root logger的屬性，這個root logger就是默認的logger日志。

 

修改后的如下：

File：logger.conf
 
[formatters]
keys=default, data
 
[formatter_default]
format=%(asctime)s - %(name)s - %(levelname)s - %(message)s
class=logging.Formatter
 
[formatter_data]
format=%(asctime)s|%(message)s
class=logging.Formatter
 
[handlers]
keys=console, error_file, data_file
 
[handler_console]
class=logging.StreamHandler
formatter=default
args=tuple()
 
[handler_error_file]
class=logging.FileHandler
level=INFO
formatter=default
args=("logger.log", "a")
 
[handler_data_file]
class=logging.FileHandler
level=INFO
formatter=data
args=("data_new.log", "a")
 
[loggers]
keys=root, data
 
[logger_root]
level=DEBUG
handlers=console,error_file
 
[logger_data]
level=DEBUG
handlers=data_file
qualname=data
propagate=0

 

File：logger.py
 
#!/bin/env python
 
import logging
from logging.config import logging
 
class Test(object):
    """docstring for Test"""
    def __init__(self):
        self.logger = logging.getLogger(__name__)
 
    def test_func(self):
        self.logger.error('test_func function')
 
class Worker(object):
    """docstring for Worker"""
    def __init__(self):
        logging.config.fileConfig("logger.conf")
        self.logger = logging.getLogger(__name__)
        self.data_logger = logging.getLogger('data')
 
    def test_logger(self):
        self.data_logger.error("test_logger function")
        instance = Test()
        self.data_logger.error("test_logger output")
        instance.test_func()
 
 
def main():
    worker = Worker()
    worker.test_logger()
 
if __name__ == '__main__':
    main()