Exception 'PosixPath' object is not iterable when using the Herbie xarray method

[mattatwork26]

There appears to be a bug in the Herbie.xarray method where the file path is not made into a string before calling cfgrib.open_datasets

Logs in question:

🏋🏻‍♂️ Found  2022-Feb-09 00:00 UTC F01 [HRRR] [product=sfc] GRIB2 file from aws and index file from aws.

Search string: APCP:surface:0-1 hour
👨🏻‍🏭 Created directory: [/tmp/hrrr/20220209]
📇 Download subset: [HRRR] model [sfc] product run at 2022-Feb-09 00:00 UTC F01
 cURL from https://noaa-hrrr-bdp-pds.s3.amazonaws.com/hrrr.20220209/conus/hrrr.t00z.wrfsfcf01.grib2
   1: GRIB_message=84  :APCP:surface:0-1 hour acc fcst
indexpath value  is ignored
No results found for search string: APCP:surface:0-1 hour, Exception: 'PosixPath' object is not iterable

After changing

        Hxr = cfgrib.open_datasets(
            self.get_localFilePath(searchString=searchString),
            backend_kwargs=backend_kwargs,
        )

to

        fp = self.get_localFilePath(searchString=searchString)
        Hxr = cfgrib.open_datasets(
            str(fp),
            backend_kwargs=backend_kwargs,
        )

in the herbie.archive xarray method, the exception no longer occurs.

[mattatwork26]

this is addressed in PR #43

[blaylockbk]

Thanks for reporting this @mattatwork26 and the pull request.
Can you tell me the version of python and cfgrib you are using?

[mattatwork26]

Np, thanks for the package

cfgrib 0.9.10.0
python 3.9.1

Just for clarity, the PR is not mine.

[blaylockbk]

This is interesting. I was not able to recreate the problem with the following:

• Python version 3.9.5
• cfgrib 0.9.9.1

from herbie.archive import Herbie
date = '2022-02-09T00:00'
fxx = 1
H = Herbie(date, model='hrrr', fxx=1)

ds = H.xarray('APCP:surface:0-1 hour')
ds

I'll have to look more into this later. I like that the PR gets around this by converting the path back into a string, but it may be that the latest release of cfgrib has an issue opening pathlib.Path objects that needs to be reported.

[blaylockbk]

Ok, I was curious and had to see what was wrong. It does appear to be an issue with cfgrib. When I updated to 0.9.10.0, I got the same error. See ecmwf/cfgrib#282

On the Herbie side of things, for now, I updated the recommended environment.yml file to use cfgrib=0.9.9.1.

- cfgrib=0.9.9.1

[mattatwork26]

I can confirm that using version cfgrib 0.9.9.1 resolves my issue, thanks!

[blaylockbk]

Looks like this will be fixed in cfgrib 0.9.10.1 😄
ecmwf/cfgrib#282

[blaylockbk]

Fixed in https://github.com/ecmwf/cfgrib/tree/0.9.10.1.
Waiting to see what happens with ecmwf/cfgrib#293