Merge pull request #1 from Mikejmnez/new_branch

moved definitions to zarr backends

Author: Miguel Jimenez

xarray/backends/api.py

@@ -567,7 +567,7 @@ def maybe_decode_store(store, lock=False):
             ds2 = ds.chunk(chunks, name_prefix=name_prefix, token=token)
             ds2._file_obj = ds._file_obj
 
-        else:  # file is zarr!
+        else:
 
             # adapted from Dataset.Chunk() and taken from open_zarr
             if not isinstance(chunks, (int, dict)):
@@ -579,58 +579,11 @@ def maybe_decode_store(store, lock=False):
             if isinstance(chunks, int):
                 chunks = dict.fromkeys(ds.dims, chunks)
 
-            if isinstance(chunks, tuple) and len(chunks) == len(ds.dims):
-                chunks = dict(zip(ds.dims, chunks))
-
-            def get_chunk(name, var, chunks):
-                chunk_spec = dict(zip(var.dims, var.encoding.get("chunks")))
-
-                # Coordinate labels aren't chunked
-                if var.ndim == 1 and var.dims[0] == name:
-                    return chunk_spec
-
-                if chunks == "auto":
-                    return chunk_spec
-
-                for dim in var.dims:
-                    if dim in chunks:
-                        spec = chunks[dim]
-                        if isinstance(spec, int):
-                            spec = (spec,)
-                        if isinstance(spec, (tuple, list)) and chunk_spec[dim]:
-                            if any(s % chunk_spec[dim] for s in spec):
-                                warnings.warn(
-                                    "Specified Dask chunks %r would "
-                                    "separate Zarr chunk shape %r for "
-                                    "dimension %r. This significantly "
-                                    "degrades performance. Consider "
-                                    "rechunking after loading instead."
-                                    % (chunks[dim], chunk_spec[dim], dim),
-                                    stacklevel=2,
-                                )
-                        chunk_spec[dim] = chunks[dim]
-                return chunk_spec
-
-            def maybe_chunk(name, var, chunks):
-                chunk_spec = get_chunk(name, var, chunks)
-
-                if (var.ndim > 0) and (chunk_spec is not None):
-                    # does this cause any data to be read?
-                    token2 = tokenize(name, var._data)
-                    name2 = "zarr-%s" % token2
-                    var = var.chunk(chunk_spec, name=name2, lock=None)
-                    if overwrite_encoded_chunks and var.chunks is not None:
-                        var.encoding["chunks"] = tuple(x[0] for x in var.chunk)
-                    return var
-                else:
-                    return var
-
-            variables = {k: maybe_chunk(k, v, chunks) for k, v in ds.variables.items()}
+            variables = {k: backends.ZarrStore.open_group.maybe_chunk(k, v, chunks) for k, v in ds.variables.items()}
             ds2 = ds._replace_vars_and_dims(variables)
         return ds2
     else:
         ds2 = ds
-
     return ds2
 
 

xarray/backends/zarr.py

@@ -358,6 +358,48 @@ def encode_variable(self, variable):
     def encode_attribute(self, a):
         return encode_zarr_attr_value(a)
 
+
+    def get_chunk(name, var, chunks):
+        chunk_spec = dict(zip(var.dims, var.encoding.get("chunks")))
+
+        # Coordinate labels aren't chunked
+        if var.ndim == 1 and var.dims[0] == name:
+            return chunk_spec
+
+        if chunks == "auto":
+            return chunk_spec
+
+        for dim in var.dims:
+            if dim in chunks:
+                spec = chunks[dim]
+                if isinstance(spec, int):
+                    spec = (spec,)
+                if isinstance(spec, (tuple, list)) and chunk_spec[dim]:
+                    if any(s % chunk_spec[dim] for s in spec):
+                        warnings.warn(
+                            "Specified Dask chunks %r would "
+                            "separate Zarr chunk shape %r for "
+                            "dimension %r. This significantly "
+                            "degrades performance. Consider "
+                            "rechunking after loading instead."
+                            % (chunks[dim], chunk_spec[dim], dim),
+                            stacklevel=2,
+                        )
+                chunk_spec[dim] = chunks[dim]
+        return chunk_spec
+
+    def maybe_chunk(name, var, chunks):
+        chunk_spec = get_chunk(name, var, chunks)
+
+        if (var.ndim > 0) and (chunk_spec is not None):
+            # does this cause any data to be read?
+            token2 = tokenize(name, var._data)
+            name2 = "zarr-%s" % token2
+            var = var.chunk(chunk_spec, name=name2, lock=None)
+            if overwrite_encoded_chunks and var.chunks is not None:
+                var.encoding["chunks"] = tuple(x[0] for x in var.chunk)
+        return var
+
     def store(
         self,
         variables,