feat: add env var overrides for conversion parameters

Add OVERRIDE_GROUPS, OVERRIDE_EXTRA_FLAGS, OVERRIDE_SPATIAL_CHUNK,
OVERRIDE_TILE_WIDTH environment variables to override collection registry
defaults at runtime.

Enables production parameter tuning and testing without code deployment.

Tests: 97 passing (+7), coverage: 91% for get_conversion_params.py

Author: wietzesuijker

pyproject.toml

@@ -55,7 +55,7 @@ packages = ["scripts"]
 [tool.pytest.ini_options]
 minversion = "8.0"
 testpaths = ["tests"]
-pythonpath = ["scripts"]  # Fix import resolution for tests
+pythonpath = ["scripts"] # Fix import resolution for tests
 python_files = ["test_*.py"]
 python_classes = ["Test*"]
 python_functions = ["test_*"]

scripts/get_conversion_params.py

@@ -5,16 +5,24 @@
 different satellite collections, enabling the workflow template to use
 data-driven configuration instead of hard-coded bash conditionals.
 
+Environment Variable Overrides (for testing/debugging):
+    OVERRIDE_GROUPS: Override groups parameter
+    OVERRIDE_EXTRA_FLAGS: Override extra_flags parameter
+    OVERRIDE_SPATIAL_CHUNK: Override spatial_chunk parameter
+    OVERRIDE_TILE_WIDTH: Override tile_width parameter
+
 Usage:
     python3 get_conversion_params.py --collection sentinel-1-l1-grd
     python3 get_conversion_params.py --collection sentinel-2-l2a --format json
     python3 get_conversion_params.py --collection sentinel-2-l2a --param groups
+    OVERRIDE_GROUPS="/custom/path" python3 get_conversion_params.py --collection sentinel-2-l2a
 """
 
 from __future__ import annotations
 
 import argparse
 import json
+import os
 import sys
 from typing import Any, cast
 
@@ -58,6 +66,12 @@ def _match_collection_config(collection_id: str) -> dict[str, Any] | None:
 def get_conversion_params(collection_id: str) -> dict[str, Any]:
     """Get conversion parameters for collection.
 
+    Environment variables can override configuration values:
+    - OVERRIDE_GROUPS: Override groups parameter
+    - OVERRIDE_EXTRA_FLAGS: Override extra_flags parameter
+    - OVERRIDE_SPATIAL_CHUNK: Override spatial_chunk parameter (integer)
+    - OVERRIDE_TILE_WIDTH: Override tile_width parameter (integer)
+
     Args:
         collection_id: Collection identifier (e.g., sentinel-1-l1-grd-dp-test)
 
@@ -75,7 +89,19 @@ def get_conversion_params(collection_id: str) -> dict[str, Any]:
             raise ValueError(f"No config for collection {collection_id}")
         config = default_config
 
-    return cast(dict[str, Any], config.get("conversion", {}))
+    conversion_params = cast(dict[str, Any], config.get("conversion", {}))
+
+    # Apply environment variable overrides (useful for testing/debugging)
+    return {
+        "groups": os.getenv("OVERRIDE_GROUPS", conversion_params.get("groups", "")),
+        "extra_flags": os.getenv("OVERRIDE_EXTRA_FLAGS", conversion_params.get("extra_flags", "")),
+        "spatial_chunk": int(
+            os.getenv("OVERRIDE_SPATIAL_CHUNK", str(conversion_params.get("spatial_chunk", 4096)))
+        ),
+        "tile_width": int(
+            os.getenv("OVERRIDE_TILE_WIDTH", str(conversion_params.get("tile_width", 512)))
+        ),
+    }
 
 
 def main(argv: list[str] | None = None) -> int:

tests/unit/test_get_conversion_params.py

@@ -1,6 +1,7 @@
 """Tests for get_conversion_params.py - Collection registry logic."""
 
 import json
+import os
 
 import pytest
 
@@ -160,3 +161,66 @@ def test_unknown_collection_uses_default(self, capsys):
         captured = capsys.readouterr()
         # Should fall back to S2 default
         assert "ZARR_GROUPS='/quality/l2a_quicklook/r10m'" in captured.out
+
+
+class TestEnvironmentVariableOverrides:
+    """Test environment variable override functionality."""
+
+    def test_override_groups(self, monkeypatch):
+        """OVERRIDE_GROUPS overrides default groups."""
+        monkeypatch.setenv("OVERRIDE_GROUPS", "/custom/groups")
+        params = get_conversion_params("sentinel-2-l2a")
+        assert params["groups"] == "/custom/groups"
+        assert params["spatial_chunk"] == 4096  # Other params unchanged
+
+    def test_override_extra_flags(self, monkeypatch):
+        """OVERRIDE_EXTRA_FLAGS overrides default flags."""
+        monkeypatch.setenv("OVERRIDE_EXTRA_FLAGS", "--custom-flag")
+        params = get_conversion_params("sentinel-1-l1-grd")
+        assert params["extra_flags"] == "--custom-flag"
+
+    def test_override_spatial_chunk(self, monkeypatch):
+        """OVERRIDE_SPATIAL_CHUNK overrides default chunk size."""
+        monkeypatch.setenv("OVERRIDE_SPATIAL_CHUNK", "8192")
+        params = get_conversion_params("sentinel-2-l2a")
+        assert params["spatial_chunk"] == 8192
+        assert isinstance(params["spatial_chunk"], int)
+
+    def test_override_tile_width(self, monkeypatch):
+        """OVERRIDE_TILE_WIDTH overrides default tile width."""
+        monkeypatch.setenv("OVERRIDE_TILE_WIDTH", "1024")
+        params = get_conversion_params("sentinel-1-l1-grd")
+        assert params["tile_width"] == 1024
+        assert isinstance(params["tile_width"], int)
+
+    def test_multiple_overrides(self, monkeypatch):
+        """Multiple overrides work together."""
+        monkeypatch.setenv("OVERRIDE_GROUPS", "/test/path")
+        monkeypatch.setenv("OVERRIDE_SPATIAL_CHUNK", "2048")
+        params = get_conversion_params("sentinel-2-l2a")
+        assert params["groups"] == "/test/path"
+        assert params["spatial_chunk"] == 2048
+        # Non-overridden values remain default
+        assert params["extra_flags"] == "--crs-groups /quality/l2a_quicklook/r10m"
+
+    def test_override_empty_string(self, monkeypatch):
+        """Empty string override is allowed."""
+        monkeypatch.setenv("OVERRIDE_EXTRA_FLAGS", "")
+        params = get_conversion_params("sentinel-1-l1-grd")
+        assert params["extra_flags"] == ""
+
+    def test_no_override_uses_default(self):
+        """Without env vars, uses configuration defaults."""
+        # Ensure no env vars are set
+        for var in [
+            "OVERRIDE_GROUPS",
+            "OVERRIDE_EXTRA_FLAGS",
+            "OVERRIDE_SPATIAL_CHUNK",
+            "OVERRIDE_TILE_WIDTH",
+        ]:
+            if var in os.environ:
+                del os.environ[var]
+
+        params = get_conversion_params("sentinel-2-l2a")
+        assert params["groups"] == "/quality/l2a_quicklook/r10m"
+        assert params["spatial_chunk"] == 4096