add sel argument

tests/test_20_open_dataset.py

@@ -1,4 +1,6 @@
+from collections.abc import Hashable
 from pathlib import Path
+from typing import Any
 
 import pytest
 import xarray as xr
@@ -103,3 +105,34 @@ def test_combine_coords(tmp_path: Path, index_node: str) -> None:
     )
     assert set(ds.coords) == {"areacella", "lat", "lon", "experiment_id", "orog"}
     assert not ds.data_vars
+
+
+@pytest.mark.parametrize(
+    "sel,expected_size",
+    [
+        ({}, 12),
+        ({"time": "2019-01"}, 1),
+        ({"time": {"slice": ["2019-01", "2019-02"]}}, 2),
+    ],
+)
+def test_time_selection(
+    tmp_path: Path,
+    index_node: str,
+    sel: dict[Hashable, Any],
+    expected_size: int,
+) -> None:
+    esgpull_path = tmp_path / "esgpull"
+    selection = {
+        "query": [
+            '"tas_Amon_EC-Earth3-CC_ssp245_r1i1p1f1_gr_201901-201912.nc"',
+        ]
+    }
+    ds = xr.open_dataset(
+        selection,  # type: ignore[arg-type]
+        esgpull_path=esgpull_path,
+        engine="esgf",
+        index_node=index_node,
+        chunks={},
+        sel=sel,
+    )
+    assert ds.sizes["time"] == expected_size

xarray_esgf/client.py

@@ -5,7 +5,7 @@
 from collections.abc import Callable, Hashable, Iterable
 from functools import cached_property
 from pathlib import Path
-from typing import Literal, get_args
+from typing import Any, Literal, get_args
 
 import tqdm
 import xarray as xr
@@ -117,10 +117,15 @@ def download(self) -> list[File]:
     def _open_datasets(
         self,
         concat_dims: DATASET_ID_KEYS | Iterable[DATASET_ID_KEYS] | None,
-        drop_variables: str | Iterable[str] | None = None,
-        download: bool = False,
-        show_progress: bool = True,
+        drop_variables: str | Iterable[str] | None,
+        download: bool,
+        show_progress: bool,
+        sel: dict[Hashable, Any],
     ) -> dict[str, Dataset]:
+        sel = {
+            k: slice(*v["slice"]) if isinstance(v, dict) else v for k, v in sel.items()
+        }
+
         if isinstance(concat_dims, str):
             concat_dims = [concat_dims]
         concat_dims = concat_dims or []
@@ -139,6 +144,7 @@ def _open_datasets(
                 drop_variables=drop_variables,
                 storage_options={"ssl": self.verify_ssl},
             )
+            ds = ds.sel({k: v for k, v in sel.items() if k in ds.dims})
             grouped_objects[file.dataset_id].append(ds.drop_encoding())
 
         combined_datasets = {}
@@ -173,9 +179,14 @@ def open_dataset(
         drop_variables: str | Iterable[str] | None = None,
         download: bool = False,
         show_progress: bool = True,
+        sel: dict[Hashable, Any] | None = None,
     ) -> Dataset:
         combined_datasets = self._open_datasets(
-            concat_dims, drop_variables, download, show_progress
+            concat_dims=concat_dims,
+            drop_variables=drop_variables,
+            download=download,
+            show_progress=show_progress,
+            sel=sel or {},
         )
 
         obj = xr.combine_by_coords(

xarray_esgf/engine.py

@@ -1,4 +1,4 @@
-from collections.abc import Iterable
+from collections.abc import Hashable, Iterable
 from pathlib import Path
 from typing import Any
 
@@ -22,6 +22,7 @@ def open_dataset(  # type: ignore[override]
         concat_dims: DATASET_ID_KEYS | Iterable[DATASET_ID_KEYS] | None = None,
         download: bool = False,
         show_progress: bool = True,
+        sel: dict[Hashable, Any] | None = None,
     ) -> Dataset:
         client = Client(
             selection=filename_or_obj,
@@ -36,6 +37,7 @@ def open_dataset(  # type: ignore[override]
             drop_variables=drop_variables,
             download=download,
             show_progress=show_progress,
+            sel=sel,
         )
 
     open_dataset_parameters = (