NUCAPS time format of data from CLASS

[joleenf]

Describe the bug
The Scene object is not able to load data from recently downloaded NUCAPS data from NOAA Class. There seems to have been a time format string change within the files. There is a format change of the time_coverage_start and time_coverage_end strings. I believe the format of the time variable is unchanged.

To Reproduce
Get NUCAPS EDR data from NOAA Class: (https://www.avl.class.noaa.gov/saa/products/search?datatype_family=JPSS_SND)

from datetime import datetime
from satpy import find_files_and_readers, Scene
from satpy.utils import debug_on; debug_on()

files = find_files_and_readers(start_time=datetime(2020,10,1,8,29), end_time=datetime(2020,10,1,8,32))
scn = Scene(files)

Expected behavior
The Scene object should load the files without error.

Actual results
[DEBUG: 2020-10-02 12:24:14 : satpy.scene] Setting 'PPP_CONFIG_DIR' to '/Users/joleenf/code/satpy/satpy/etc'
[DEBUG: 2020-10-02 12:24:14 : satpy.readers.yaml_reader] Reading ('/Users/joleenf/code/satpy/satpy/etc/readers/nucaps.yaml',)
[DEBUG: 2020-10-02 12:24:14 : satpy.readers.yaml_reader] Assigning to nucaps: ['NUCAPS-EDR_v2r0_npp_s202010010831030_e202010010831330_c202010011004460.nc', 'NUCAPS-EDR_v2r0_npp_s202010010829270_e202010010829570_c202010011018340.nc', 'NUCAPS-EDR_v2r0_npp_s202010010831350_e202010010832050_c202010011018180.nc', 'NUCAPS-EDR_v2r0_npp_s202010010828550_e202010010829250_c202010011017490.nc', 'NUCAPS-EDR_v2r0_npp_s202010010830310_e202010010831010_c202010011003140.nc', 'NUCAPS-EDR_v2r0_npp_s202010010829590_e202010010830290_c202010011018170.nc']
Traceback (most recent call last):
File "", line 1, in
File "/Users/joleenf/code/satpy/satpy/scene.py", line 151, in init
self._readers = self._create_reader_instances(filenames=filenames,
File "/Users/joleenf/code/satpy/satpy/scene.py", line 200, in _create_reader_instances
return load_readers(filenames=filenames,
File "/Users/joleenf/code/satpy/satpy/readers/init.py", line 495, in load_readers
reader_instance.create_filehandlers(loadables, fh_kwargs=reader_kwargs_without_filter)
File "/Users/joleenf/code/satpy/satpy/readers/yaml_reader.py", line 604, in create_filehandlers
filehandlers = self._new_filehandlers_for_filetype(filetype_info,
File "/Users/joleenf/code/satpy/satpy/readers/yaml_reader.py", line 592, in _new_filehandlers_for_filetype
return list(filtered_iter)
File "/Users/joleenf/code/satpy/satpy/readers/yaml_reader.py", line 561, in filter_fh_by_metadata
filehandler.metadata['start_time'] = filehandler.start_time
File "/Users/joleenf/code/satpy/satpy/readers/nucaps.py", line 90, in start_time
return self._parse_datetime(self['/attr/time_coverage_start'])
File "/Users/joleenf/code/satpy/satpy/readers/nucaps.py", line 84, in _parse_datetime
return datetime.strptime(datestr, "%Y-%m-%dT%H:%M:%S.%fZ")
File "/Users/joleenf/miniconda3/envs/satpy-dev/lib/python3.8/_strptime.py", line 568, in _strptime_datetime
tt, fraction, gmtoff_fraction = _strptime(data_string, format)
File "/Users/joleenf/miniconda3/envs/satpy-dev/lib/python3.8/_strptime.py", line 349, in _strptime
raise ValueError("time data %r does not match format %r" %
ValueError: time data '2020-10-01T08:31:03Z' does not match format '%Y-%m-%dT%H:%M:%S.%fZ'

Environment Info:

• OS: OSX 10.15.6 (Darwin simple.local 19.6.0 Darwin Kernel Version 19.6.0: Thu Jun 18 20:49:00 PDT 2020; root:xnu-6153.141.1~1/RELEASE_X86_64 x86_64)

• Satpy Version: 0.23

• PyResample Version: 1.16.0

• Readers and writers dependencies Readers
  =======
  abi_l1b: ok
  abi_l1b_scmi: ok
  abi_l2_nc: ok
  acspo: ok
  agri_l1: ok
  ahi_hrit: ok
  ahi_hsd: ok
  ahi_l1b_gridded_bin: ok
  ami_l1b: ok
  amsr2_l1b: ok
  amsr2_l2: ok
  avhrr_l1b_aapp: ok
  avhrr_l1b_eps: ok
  avhrr_l1b_gaclac: cannot find module 'satpy.readers.avhrr_l1b_gaclac' (No module named 'pygac')
  avhrr_l1b_hrpt: cannot find module 'satpy.readers.hrpt' (No module named 'pygac')
  caliop_l2_cloud: cannot find module 'satpy.readers.caliop_l2_cloud' (No module named 'pyhdf')
  clavrx: cannot find module 'satpy.readers.clavrx' (No module named 'pyhdf')
  cmsaf-claas2_l2_nc: ok
  electrol_hrit: ok
  fci_l1c_fdhsi: ok
  fci_l2_nc: ok
  generic_image: ok
  geocat: ok
  ghrsst_l3c_sst: cannot find module 'satpy.readers.ghrsst_l3c_sst' (cannot import name 'Dataset' from 'satpy.dataset' (/Users/joleenf/miniconda3/envs/satpy/lib/python3.8/site-packages/satpy/dataset/init.py))
  glm_l2: ok
  goes-imager_hrit: ok
  goes-imager_nc: ok
  gpm_imerg: ok
  grib: cannot find module 'satpy.readers.grib' (No module named 'pygrib')
  hsaf_grib: cannot find module 'satpy.readers.hsaf_grib' (No module named 'pygrib')
  hy2_scat_l2b_h5: ok
  iasi_l2: ok
  iasi_l2_so2_bufr: cannot find module 'satpy.readers.iasi_l2_so2_bufr' (('Missing eccodes-python and/or eccodes C-library installation. Use conda to install eccodes.\n Error: ', ModuleNotFoundError("No module named 'eccodes'")))
  jami_hrit: ok
  li_l2: cannot find module 'satpy.readers.li_l2' (No module named 'h5netcdf')
  maia: ok
  mersi2_l1b: ok
  mimicTPW2_comp: ok
  modis_l1b: cannot find module 'satpy.readers.modis_l1b' (No module named 'pyhdf')
  modis_l2: cannot find module 'satpy.readers.modis_l2' (No module named 'pyhdf')
  msi_safe: cannot find module 'satpy.readers.msi_safe' (No module named 'glymur')
  mtsat2-imager_hrit: ok
  nucaps: ok
  nwcsaf-geo: ok
  nwcsaf-msg2013-hdf5: ok
  nwcsaf-pps_nc: ok
  olci_l1b: ok
  olci_l2: ok
  omps_edr: ok
  safe_sar_l2_ocn: ok
  sar-c_safe: ok
  scatsat1_l2b: cannot find module 'satpy.readers.scatsat1_l2b' (cannot import name 'Dataset' from 'satpy.dataset' (/Users/joleenf/miniconda3/envs/satpy/lib/python3.8/site-packages/satpy/dataset/init.py))
  seviri_l1b_hrit: ok
  seviri_l1b_icare: cannot find module 'satpy.readers.seviri_l1b_icare' (No module named 'pyhdf')
  seviri_l1b_native: ok
  seviri_l1b_nc: ok
  seviri_l2_bufr: cannot find module 'satpy.readers.seviri_l2_bufr' (Missing eccodes-python and/or eccodes C-library installation. Use conda to install eccodes)
  seviri_l2_grib: cannot find module 'satpy.readers.seviri_l2_grib' (Missing eccodes-python and/or eccodes C-library installation. Use conda to install eccodes)
  slstr_l1b: ok
  slstr_l2: ok
  smos_l2_wind: ok
  tropomi_l2: ok
  vaisala_gld360: ok
  vii_l1b_nc: ok
  vii_l2_nc: ok
  viirs_compact: ok
  viirs_edr_active_fires: ok
  viirs_edr_flood: cannot find module 'satpy.readers.viirs_edr_flood' (No module named 'pyhdf')
  viirs_l1b: ok
  viirs_sdr: ok
  virr_l1b: ok
  Writers
  =======
  cf: ok
  geotiff: ok
  mitiff: ok
  ninjotiff: cannot find module 'satpy.writers.ninjotiff' (No module named 'pyninjotiff')
  scmi: ok
  simple_image: ok
  Extras
  ======
  cartopy: No module named 'cartopy'
  geoviews: No module named 'geoviews'

[djhoese]

Looks like maybe we should do a double check. First with the format with the .%f part and then if that fails, try again without the .%f part (note the . is in the format which makes it a required character).