Proof of concept to allow iterable instead of sequence for mosaics.

iterable_example.ipynb

@@ -0,0 +1,86 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 5,
+   "id": "760550cf-4feb-44b4-9f7f-ce065fde279b",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "[-93.01025390625037, 44.99588261816585, -92.98828125000037, 45.01141864227766]\n",
+      "https://planetarycomputer.microsoft.com/api/stac/v1/search?limit=10&bbox=-93.01025390625037%2C44.99588261816585%2C-92.98828125000037%2C45.01141864227766&collections=naip&fields=\n",
+      "4 4 4\n",
+      "4\n",
+      "CPU times: user 383 ms, sys: 7.44 ms, total: 391 ms\n",
+      "Wall time: 1.08 s\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%time\n",
+    "from pystac_client import Client\n",
+    "from rio_tiler.mosaic import mosaic_reader\n",
+    "from rio_tiler.io import Reader\n",
+    "from rio_tiler.models import ImageData\n",
+    "import morecantile\n",
+    "\n",
+    "tms = morecantile.tms.get(\"WebMercatorQuad\")\n",
+    "x, y, z = tms.tile(-93,45,14)\n",
+    "bbox = list(tms.bounds(morecantile.Tile(x, y, z)))\n",
+    "print(bbox)\n",
+    "\n",
+    "def reader(asset: str, *args, **kwargs) -> ImageData:\n",
+    "    with Reader(asset) as src:\n",
+    "        return src.tile(*args, **kwargs)\n",
+    "\n",
+    "\n",
+    "catalog = Client.open('https://planetarycomputer.microsoft.com/api/stac/v1')\n",
+    "results = catalog.search(\n",
+    "    limit=10,\n",
+    "    max_items=100,\n",
+    "    bbox=bbox,\n",
+    "    collections=[\"naip\"],\n",
+    "    fields={\"include\":[\"assets.image.href\"], \"exclude\":[\"links\"]}\n",
+    ")\n",
+    "print(results.url_with_parameters())\n",
+    "items=results.items_as_dicts()\n",
+    "\n",
+    "assets = (item['assets']['image']['href'] for item in items)\n",
+    "\n",
+    "img, used = mosaic_reader(assets, reader, x, y, z, threads=4)\n",
+    "print(len(used))\n"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "python-3.10.12",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.10.12"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}

rio_tiler/mosaic/reader.py

@@ -2,7 +2,18 @@
 
 import warnings
 from inspect import isclass
-from typing import Any, Callable, List, Optional, Sequence, Tuple, Type, Union, cast
+from typing import (
+    Any,
+    Callable,
+    Iterator,
+    List,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+    cast,
+)
 
 import numpy
 from rasterio.crs import CRS
@@ -23,7 +34,7 @@
 
 
 def mosaic_reader(  # noqa: C901
-    mosaic_assets: Sequence,
+    mosaic_assets: Union[Iterator, Sequence],
     reader: Callable[..., ImageData],
     *args: Any,
     pixel_selection: Union[Type[MosaicMethodBase], MosaicMethodBase] = FirstMethod,
@@ -36,7 +47,7 @@ def mosaic_reader(  # noqa: C901
 
     Args:
 
-        mosaic_assets (sequence): List of assets.
+        mosaic_assets (Sequence or Iterator): List of assets.
         reader (callable): Reader function. The function MUST take `(asset, *args, **kwargs)` as arguments, and MUST return an ImageData.
         args (Any): Argument to forward to the reader function.
         pixel_selection (MosaicMethod, optional): Instance of MosaicMethodBase class. Defaults to `rio_tiler.mosaic.methods.defaults.FirstMethod`.
@@ -76,9 +87,11 @@ def mosaic_reader(  # noqa: C901
             "'rio_tiler.mosaic.methods.base.MosaicMethodBase'"
         )
 
-    if not chunk_size:
+    if not isinstance(mosaic_assets, Iterator) and not chunk_size:
         chunk_size = threads if threads > 1 else len(mosaic_assets)
 
+    chunk_size = chunk_size or threads
+
     assets_used: List = []
     crs: Optional[CRS]
     bounds: Optional[BBox]

rio_tiler/utils.py

@@ -1,8 +1,20 @@
 """rio_tiler.utils: utility functions."""
 
+import itertools
 import warnings
 from io import BytesIO
-from typing import Any, Dict, Generator, List, Optional, Sequence, Tuple, Union
+from typing import (
+    Any,
+    Dict,
+    Generator,
+    Iterable,
+    Iterator,
+    List,
+    Optional,
+    Sequence,
+    Tuple,
+    Union,
+)
 
 import numpy
 import rasterio
@@ -26,10 +38,13 @@
 from rio_tiler.types import BBox, ColorMapType, IntervalTuple, RIOResampling
 
 
-def _chunks(my_list: Sequence, chuck_size: int) -> Generator[Sequence, None, None]:
+def _chunks(my_list: Iterable, chuck_size: int) -> Generator[Sequence, None, None]:
     """Yield successive n-sized chunks from l."""
-    for i in range(0, len(my_list), chuck_size):
-        yield my_list[i : i + chuck_size]
+    if not isinstance(my_list, Iterator):
+        my_list = iter(my_list)
+
+    while chunk := tuple(itertools.islice(my_list, chuck_size)):
+        yield chunk
 
 
 def get_array_statistics(

tests/test_mosaic.py

@@ -286,6 +286,20 @@ class aClass(object):
     assert m.dtype == "uint8"
 
 
+def test_mosaic_tiler_iter():
+    """Test mosaic tiler with iterator input."""
+    assets_iter = iter(assets)
+
+    (t, m), assets_used = mosaic.mosaic_reader(assets_iter, _read_tile, x, y, z)
+    assert t.shape == (3, 256, 256)
+    assert m.shape == (256, 256)
+    assert m.all()
+    # Should only have value of 1
+    assert numpy.unique(t[0, m == 255]).tolist() == [1]
+    assert t.dtype == "uint16"
+    assert m.dtype == "uint8"
+
+
 def mock_rasterio_open(asset):
     """Mock rasterio Open."""
     assert asset.startswith("http://somewhere-over-the-rainbow.io")