sqme: dask mode from env

odc/loader/_builder.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import dataclasses
+import os
 from concurrent.futures import ThreadPoolExecutor
 from datetime import datetime
 from typing import (
@@ -51,6 +52,8 @@
     T,
 )
 
+DaskBuilderMode = Literal["mem", "concurrency"]
+
 
 class MkArray(Protocol):
     """Internal interface."""
@@ -143,6 +146,13 @@ def resolve_sources_dask(
         ]
 
 
+def _default_dask_mode() -> DaskBuilderMode:
+    mode = os.environ.get("ODC_STAC_DASK_MODE", "mem")
+    if mode == "concurrency":
+        return "concurrency"
+    return "mem"
+
+
 class DaskGraphBuilder:
     """
     Build xarray from parsed metadata.
@@ -160,7 +170,7 @@ def __init__(
         env: Dict[str, Any],
         rdr: ReaderDriver,
         chunks: Mapping[str, int],
-        mode: Literal["auto"] | Literal["mem"] | Literal["concurrency"] = "auto",
+        mode: DaskBuilderMode | Literal["auto"] = "auto",
     ) -> None:
         gbox = gbt.base
         assert isinstance(gbox, GeoBox)
@@ -169,7 +179,8 @@ def __init__(
         chunks = {**chunks}
         chunks.update(dict(zip(["time", "y", "x"], chunk_tyx)))
         if mode == "auto":
-            mode = "mem"  # current default
+            # "mem" unless overwriten by env var
+            mode = _default_dask_mode()
 
         self.cfg = cfg
         self.template = template