Python decorator to change loglevel within a function.

python-logger.py

import logging

LOG = logging.getLogger(__name__)
logging.basicConfig(format="[%(levelname)8s] %(message)s    (%(funcName)s@%(filename)s:%(lineno)s)")
LOG.setLevel(logging.DEBUG)

LOGLEVEL_FUNCS = {} # autoreload workaround https://github.com/ipython/ipython/issues/11099#issuecomment-382029692
def loglevel(level):
  def outer(func):
    LOG.debug(f"loglevel {level} for function {func.__qualname__}")
    LOGLEVEL_FUNCS[func.__qualname__] = (level, func)
    @wraps(func)
    def inner(*args, **kwargs):
      level, f = LOGLEVEL_FUNCS[func.__qualname__]
      oldlevel = LOG.getEffectiveLevel()
      #print(f">LOGLEVEL {level}")
      LOG.setLevel(level)
      try:
        res = f(*args, **kwargs)
        if isinstance(res, Iterator):
          return loglevel_iterator(level, res)
        else:
          return res
      finally:
        LOG.setLevel(oldlevel)
        #print(f"<LOGLEVEL {oldlevel}")
    return inner
  return outer
def loglevel_iterator(level, iterator):
  try:
    oldlevel = LOG.getEffectiveLevel()
    LOG.setLevel(level)
    for i in iterator:
      LOG.setLevel(oldlevel)
      yield i
      oldlevel = LOG.getEffectiveLevel()
      LOG.setLevel(level)
  finally:
    LOG.setLevel(oldlevel)