Using cfgrib with xarray.open_dataset fails due to "'EntryPoint' object has no attribute 'module_name'" AttributeError

[Josh Dorrington]

Versions and dependencies

I have installed cfgrib using mamba. I have checked that cfgrib is installed correctly:

>>python -m cfgrib selfcheck
Found: ecCodes v2.26.0.
Your system is ready.

and I have retrieved the test grib file using wget.

>>import xarray as xr
>>import sys

>>print(sys.version)
3.9.10 | packaged by conda-forge | (main, Feb  1 2022, 21:24:11) 
[GCC 9.4.0]

>>print(xr.__version__)
0.20.1

Nature of Error
When I run:
xr.open_dataset('era5-levels-members.grib',engine='cfgrib')

I receive an error (posted in full at the bottom) which seems to derive from this object:
EntryPoint(name='cfgrib', value='cfgrib.xarray_plugin:CfGribBackend', group='xarray.backends')
having no attribute 'module_name', which occurs at the bottom of the following stacktrace:

xr.open_dataset->plugins.get_backend(engine)->list_engines()->build_engines(entrypoints)->remove_duplicates(entrypoints)

I would appreciate any assistance in getting this working!

Full error message:

AttributeError                            Traceback (most recent call last)
/tmp/ipykernel_23372/811187540.py in <module>
      4 
      5 get_ipython().run_line_magic('debug', '')
----> 6 xr.open_dataset('era5-levels-members.grib',engine='cfgrib')

~/miniconda3/lib/python3.9/site-packages/xarray/backends/api.py in open_dataset(filename_or_obj, engine, chunks, cache, decode_cf, mask_and_scale, decode_times, decode_timedelta, use_cftime, concat_characters, decode_coords, drop_variables, backend_kwargs, *args, **kwargs)
    479         engine = plugins.guess_engine(filename_or_obj)
    480 
--> 481     backend = plugins.get_backend(engine)
    482 
    483     decoders = _resolve_decoders_kwargs(

~/miniconda3/lib/python3.9/site-packages/xarray/backends/plugins.py in get_backend(engine)
    156     """Select open_dataset method based on current engine."""
    157     if isinstance(engine, str):
--> 158         engines = list_engines()
    159         if engine not in engines:
    160             raise ValueError(

~/miniconda3/lib/python3.9/site-packages/xarray/backends/plugins.py in list_engines()
    101 def list_engines():
    102     entrypoints = entry_points().get("xarray.backends", ())
--> 103     return build_engines(entrypoints)
    104 
    105 

~/miniconda3/lib/python3.9/site-packages/xarray/backends/plugins.py in build_engines(entrypoints)
     90         if backend.available:
     91             backend_entrypoints[backend_name] = backend
---> 92     entrypoints = remove_duplicates(entrypoints)
     93     external_backend_entrypoints = backends_dict_from_pkg(entrypoints)
     94     backend_entrypoints.update(external_backend_entrypoints)

~/miniconda3/lib/python3.9/site-packages/xarray/backends/plugins.py in remove_duplicates(entrypoints)
     27         matches_len = len(matches)
     28         if matches_len > 1:
---> 29             selected_module_name = matches[0].module_name
     30             all_module_names = [e.module_name for e in matches]
     31             warnings.warn(

AttributeError: 'EntryPoint' object has no attribute 'module_name'

[Iain Russell]

Hi @joshdorrington,

I've just installed cfgrib into a mamba environment and it worked ok for me. I think it's worth double-checking that everything is installed where you think it is, e.g. that cfgrib is installed into the same environment that xarray is installed into.

Best regards,
Iain

[Michael Niklas]

This has been fixed 1 year ago in xarray: pydata/xarray#5959
Consider updating xarray.