logging error with the latest bluesky master

[mrakitin]

We observed this issue with @dmgav yesterday when we tried to debug multiruns issue on the latest master. It seems something is broken, either on the client side (likely), or on the library side (unlikely):

AttributeError                            Traceback (most recent call last)
/opt/conda_envs/collection-2020-1.0rc1/lib/python3.7/site-packages/IPython/core/shellapp.py in _exec_file(self, fname, shell_futures)
    338                                                  self.shell.user_ns,
    339                                                  shell_futures=shell_futures,
--> 340                                                  raise_exceptions=True)
    341         finally:
    342             sys.argv = save_argv

/opt/conda_envs/collection-2020-1.0rc1/lib/python3.7/site-packages/IPython/core/interactiveshell.py in safe_execfile(self, fname, exit_ignore, raise_exceptions, shell_futures, *where)
   2720                 py3compat.execfile(
   2721                     fname, glob, loc,
-> 2722                     self.compile if shell_futures else None)
   2723             except SystemExit as status:
   2724                 # If the call was made with 0 or None exit status (sys.exit(0)

/opt/conda_envs/collection-2020-1.0rc1/lib/python3.7/site-packages/IPython/utils/py3compat.py in execfile(fname, glob, loc, compiler)
    166     with open(fname, 'rb') as f:
    167         compiler = compiler or compile
--> 168         exec(compiler(f.read(), fname, 'exec'), glob, loc)
    169
    170 # Refactor print statements in doctests.

~/.ipython/profile_collection/startup/00-startup.py in <module>
      6
      7 from bluesky.log import current_handler
----> 8 current_handler.setLevel('CRITICAL')
      9
     10 # After the above call, you will now have the following in your namespace:

AttributeError: 'NoneType' object has no attribute 'setLevel'

Should we just remove these lines as they have to be different now?

cc @danielballan @ke-zhang-rd @tacaswell

[danielballan]

The intended usage is:

from bluesky.log import config_bluesky_logging
config_bluesky_logging(level='CRITICAL')

The current_handler is a global module variable that is None at import time and will be set to a logger when (if) conifg_bluesky_logging is called.

[danielballan]

This docstring is relevant:

https://github.com/bluesky/bluesky/blob/7b2ae57ee472dd9c161a50e6e3d11f7d20f7bc5a/bluesky/log.py#L252-L258