Logging getChild not working properly

[juliotux]

When ask Astropy's logger for a child with getChild methos, the logger returns a default python logger (logging.Logger class) and not a proper astropy.logger.AstropyLogger instance. As the following examples shows:

In [1]: from astropy.logger import log                                         

In [2]: log.__class__                                                          
Out[2]: astropy.logger.AstropyLogger

In [3]: l = log.getChild('testing_child')                                      

In [4]: l.__class__                                                            
Out[4]: logging.Logger

As everything else works with AstropyLogger's record, any message generated by this child logger will raise AttributeError: 'LogRecord' object has no attribute 'origin', since default logger makeRecord do not set the origin attribute as Astropy do. This problem was noticed by @cdeil a long time ago in astropy/package-template#134 .

A reimplementation like the following one (based on _init_log()) should fix this problem, but generate another problem of multiplicity in output.

class AstropyLogger(Logger):
    def getChild(self, suffix):
        """
        Simple reimplementation of Logger.getChild
        """
        if self.root is not self:
            suffix = '.'.join((self.name, suffix))

        orig_logger_cls = logging.getLoggerClass()
        logging.setLoggerClass(AstropyLogger)
        try:
            log = logging.getLogger(suffix)
            log._set_defaults()
        finally:
            logging.setLoggerClass(orig_logger_cls)

        return log

How could we deal with this problem?