subset with time_components fails for day values which are not in the netcdf file

[cehbrecht]

• clisops version: 0.9.0
• Python version: 3.7
• Operating System:

Description

Run the subset with time_components on a cmip6 netcdf file with monthly data and choose a day component which does not exist, like day:01, then you get the following exception:

File "/usr/local/anaconda/envs/rook/lib/python3.7/site-packages/clisops/ops/subset.py", line 244, in subset
    return op.process()
  File "/usr/local/anaconda/envs/rook/lib/python3.7/site-packages/clisops/ops/base_operation.py", line 107, in process
    processed_ds = self._calculate()
  File "/usr/local/anaconda/envs/rook/lib/python3.7/site-packages/clisops/ops/subset.py", line 160, in _calculate
    result = subset_time_by_components(result, time_components=time_comps)
  File "/usr/local/anaconda/envs/rook/lib/python3.7/site-packages/clisops/core/subset.py", line 1641, in subset_time_by_components
    {idx for tc in req_t_comp for idx in t_comp_indices[tc]}
  File "/usr/local/anaconda/envs/rook/lib/python3.7/site-packages/clisops/core/subset.py", line 1641, in <setcomp>
    {idx for tc in req_t_comp for idx in t_comp_indices[tc]}
KeyError: 1

What I Did

See this notebook:
https://github.com/roocs/rooki/blob/master/notebooks/tests/test-c3s-cmip6-subset-by-point.ipynb

wf = ops.Subset(
        ops.Input(
            'tas', ['c3s-cmip6.CMIP.NCAR.CESM2-WACCM-FV2.historical.r1i1p1f1.Amon.tas.gn.v20191120']
        ),
        time="1998/2000",
        time_components="year:1998,1999,2000|month:jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec|day:01,02,03,04,05,06,07,08,09,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31"
        #time_components="year:1998,1999,2000|month:jan,feb,mar,apr,may,jun,jul,aug,sep,oct,nov,dec|day:14,15"
)
resp = wf.orchestrate()
resp.ok

[cehbrecht]

In the example I have chosen monthly data and using a “day” selector which does not exist in the data, like “day:01”. It works with “day:14,15”.

The expected behaviour should probably be to ignore non-existing selectors. This happens already … but if the selector does not appear at all in the data we get an exception. Day 14,15 appears in the data … but no other days.

ping @JamesVarndell

[agstephens]

@cehbrecht, the offending code is maybe mixing up index values with actual values:

https://github.com/roocs/clisops/blob/master/clisops/core/subset.py#L1639-L1644

So, maybe "day:01" is looking for the_selected_days[1] - so it will fail if there is only one value in the array of selected days.