Change RasterReader api, read method

Adding extra parameter for selecting subset of
bands to read.

odc/loader/_rio.py

@@ -101,8 +101,9 @@ def read(
         cfg: RasterLoadParams,
         dst_geobox: GeoBox,
         dst: Optional[np.ndarray] = None,
+        selection: Optional[slice] = None,
     ) -> Tuple[NormalizedROI, np.ndarray]:
-        return rio_read(self._src, cfg, dst_geobox, dst=dst)
+        return rio_read(self._src, cfg, dst_geobox, dst=dst, selection=selection)
 
 
 class RioDriver:
@@ -426,6 +427,7 @@ def rio_read(
     cfg: RasterLoadParams,
     dst_geobox: GeoBox,
     dst: Optional[np.ndarray] = None,
+    selection: Optional[slice] = None,
 ) -> Tuple[NormalizedROI, np.ndarray]:
     """
     Internal read method.
@@ -450,7 +452,7 @@ def rio_read(
     """
 
     try:
-        return _rio_read(src, cfg, dst_geobox, dst)
+        return _rio_read(src, cfg, dst_geobox, dst, selection=selection)
     except (
         rasterio.errors.RasterioIOError,
         rasterio.errors.RasterBlockError,
@@ -491,10 +493,12 @@ def _rio_read(
     cfg: RasterLoadParams,
     dst_geobox: GeoBox,
     dst: Optional[np.ndarray] = None,
+    selection: Optional[slice] = None,
 ) -> Tuple[NormalizedROI, np.ndarray]:
     # if resampling is `nearest` then ignore sub-pixel translation when deciding
     # whether we can just paste source into destination
     ttol = 0.9 if cfg.nearest else 0.05
+    assert selection is None, "Band selection not implemented in rio_read"
 
     with rasterio.open(src.uri, "r", sharing=False) as rdr:
         assert isinstance(rdr, rasterio.DatasetReader)

odc/loader/testing/fixtures.py

@@ -149,9 +149,12 @@ def read(
         cfg: RasterLoadParams,
         dst_geobox: GeoBox,
         dst: Optional[np.ndarray] = None,
+        selection: Optional[slice] = None,
     ) -> Tuple[NormalizedROI, np.ndarray]:
         meta = self._src.meta
         assert meta is not None
+        # TODO: handle selection
+        assert selection is None
 
         extra_dims = self._extra_dims()
         prefix_dims: Tuple[int, ...] = ()

odc/loader/types.py

@@ -367,6 +367,7 @@ def read(
         cfg: RasterLoadParams,
         dst_geobox: GeoBox,
         dst: Optional[np.ndarray] = None,
+        selection: Optional[slice] = None,
     ) -> Tuple[NormalizedROI, np.ndarray]: ...