Delete pynio backend. (pydata#8971)

* Delete pynio backend.

* cleanup test

* fix whats-new

.binder/environment.yml

@@ -28,7 +28,6 @@ dependencies:
   - pip
   - pooch
   - pydap
-  - pynio
   - rasterio
   - scipy
   - seaborn

doc/getting-started-guide/installing.rst

@@ -31,9 +31,6 @@ For netCDF and IO
 - `pydap <https://www.pydap.org>`__: used as a fallback for accessing OPeNDAP
 - `h5netcdf <https://github.com/h5netcdf/h5netcdf>`__: an alternative library for
   reading and writing netCDF4 files that does not use the netCDF-C libraries
-- `PyNIO <https://www.pyngl.ucar.edu/Nio.shtml>`__: for reading GRIB and other
-  geoscience specific file formats. Note that PyNIO is not available for Windows and
-  that the PyNIO backend may be moved outside of xarray in the future.
 - `zarr <https://zarr.readthedocs.io>`__: for chunked, compressed, N-dimensional arrays.
 - `cftime <https://unidata.github.io/cftime>`__: recommended if you
   want to encode/decode datetimes for non-standard calendars or dates before

doc/user-guide/io.rst

@@ -1294,27 +1294,6 @@ We recommend installing cfgrib via conda::
 
 .. _cfgrib: https://github.com/ecmwf/cfgrib
 
-.. _io.pynio:
-
-Formats supported by PyNIO
---------------------------
-
-.. warning::
-
-    The `PyNIO backend is deprecated`_. `PyNIO is no longer maintained`_.
-
-Xarray can also read GRIB, HDF4 and other file formats supported by PyNIO_,
-if PyNIO is installed. To use PyNIO to read such files, supply
-``engine='pynio'`` to :py:func:`open_dataset`.
-
-We recommend installing PyNIO via conda::
-
-    conda install -c conda-forge pynio
-
-.. _PyNIO: https://www.pyngl.ucar.edu/Nio.shtml
-.. _PyNIO backend is deprecated: https://github.com/pydata/xarray/issues/4491
-.. _PyNIO is no longer maintained: https://github.com/NCAR/pynio/issues/53
-
 
 CSV and other formats supported by pandas
 -----------------------------------------

doc/whats-new.rst

@@ -32,6 +32,8 @@ New Features
 
 Breaking changes
 ~~~~~~~~~~~~~~~~
+- The PyNIO backend has been deleted (:issue:`4491`, :pull:`7301`).
+  By `Deepak Cherian <https://github.com/dcherian>`_.
 
 
 Bug fixes
@@ -6806,8 +6808,7 @@ Enhancements
       datasets with a MultiIndex to a netCDF file. User contributions in this
       area would be greatly appreciated.
 
-- Support for reading GRIB, HDF4 and other file formats via PyNIO_. See
-  :ref:`io.pynio` for more details.
+- Support for reading GRIB, HDF4 and other file formats via PyNIO_.
 - Better error message when a variable is supplied with the same name as
   one of its dimensions.
 - Plotting: more control on colormap parameters (:issue:`642`). ``vmin`` and

xarray/backends/__init__.py

@@ -15,7 +15,6 @@
 from xarray.backends.netCDF4_ import NetCDF4BackendEntrypoint, NetCDF4DataStore
 from xarray.backends.plugins import list_engines, refresh_engines
 from xarray.backends.pydap_ import PydapBackendEntrypoint, PydapDataStore
-from xarray.backends.pynio_ import NioDataStore
 from xarray.backends.scipy_ import ScipyBackendEntrypoint, ScipyDataStore
 from xarray.backends.store import StoreBackendEntrypoint
 from xarray.backends.zarr import ZarrBackendEntrypoint, ZarrStore
@@ -30,7 +29,6 @@
     "InMemoryDataStore",
     "NetCDF4DataStore",
     "PydapDataStore",
-    "NioDataStore",
     "ScipyDataStore",
     "H5NetCDFStore",
     "ZarrStore",

xarray/backends/api.py

@@ -61,7 +61,7 @@
     T_NetcdfEngine = Literal["netcdf4", "scipy", "h5netcdf"]
     T_Engine = Union[
         T_NetcdfEngine,
-        Literal["pydap", "pynio", "zarr"],
+        Literal["pydap", "zarr"],
         type[BackendEntrypoint],
         str,  # no nice typing support for custom backends
         None,
@@ -79,7 +79,6 @@
     "scipy": backends.ScipyDataStore,
     "pydap": backends.PydapDataStore.open,
     "h5netcdf": backends.H5NetCDFStore.open,
-    "pynio": backends.NioDataStore,
     "zarr": backends.ZarrStore.open_group,
 }
 
@@ -420,8 +419,8 @@ def open_dataset(
         ends with .gz, in which case the file is gunzipped and opened with
         scipy.io.netcdf (only netCDF3 supported). Byte-strings or file-like
         objects are opened by scipy.io.netcdf (netCDF3) or h5py (netCDF4/HDF).
-    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "pynio", \
-        "zarr", None}, installed backend \
+    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "zarr", None}\
+        , installed backend \
         or subclass of xarray.backends.BackendEntrypoint, optional
         Engine to use when reading files. If not provided, the default engine
         is chosen based on available dependencies, with a preference for
@@ -523,7 +522,7 @@ def open_dataset(
           relevant when using dask or another form of parallelism. By default,
           appropriate locks are chosen to safely read and write files with the
           currently active dask scheduler. Supported by "netcdf4", "h5netcdf",
-          "scipy", "pynio".
+          "scipy".
 
         See engine open function for kwargs accepted by each specific engine.
 
@@ -627,8 +626,8 @@ def open_dataarray(
         ends with .gz, in which case the file is gunzipped and opened with
         scipy.io.netcdf (only netCDF3 supported). Byte-strings or file-like
         objects are opened by scipy.io.netcdf (netCDF3) or h5py (netCDF4/HDF).
-    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "pynio", \
-        "zarr", None}, installed backend \
+    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "zarr", None}\
+        , installed backend \
         or subclass of xarray.backends.BackendEntrypoint, optional
         Engine to use when reading files. If not provided, the default engine
         is chosen based on available dependencies, with a preference for
@@ -728,7 +727,7 @@ def open_dataarray(
           relevant when using dask or another form of parallelism. By default,
           appropriate locks are chosen to safely read and write files with the
           currently active dask scheduler. Supported by "netcdf4", "h5netcdf",
-          "scipy", "pynio".
+          "scipy".
 
         See engine open function for kwargs accepted by each specific engine.
 
@@ -897,8 +896,8 @@ def open_mfdataset(
         If provided, call this function on each dataset prior to concatenation.
         You can find the file-name from which each dataset was loaded in
         ``ds.encoding["source"]``.
-    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "pynio", \
-        "zarr", None}, installed backend \
+    engine : {"netcdf4", "scipy", "pydap", "h5netcdf", "zarr", None}\
+        , installed backend \
         or subclass of xarray.backends.BackendEntrypoint, optional
         Engine to use when reading files. If not provided, the default engine
         is chosen based on available dependencies, with a preference for

xarray/tests/__init__.py

@@ -99,7 +99,6 @@ def _importorskip(
     )
 
     has_h5netcdf, requires_h5netcdf = _importorskip("h5netcdf")
-has_pynio, requires_pynio = _importorskip("Nio")
 has_cftime, requires_cftime = _importorskip("cftime")
 has_dask, requires_dask = _importorskip("dask")
 with warnings.catch_warnings():