fix: skip cleanup if we can't find anything to delete (#313)

Author: ceholden

lambda_functions/cleanup_sentinel2_granules.py

@@ -51,6 +51,10 @@ def handler(event: dict, context: dict):
         Prefix=prefix,
     )
 
+    if "Contents" not in response:
+        print(f"Found 0 granule zip files for prefix={prefix}, aborting.")
+        return
+
     granule_zips = [obj["Key"] for obj in response["Contents"]]
 
     # We have three possible cases,

lambda_functions/tests/test_cleanup_sentinel2_granules.py

@@ -77,3 +77,25 @@ def test_bad_granule_id_inputs(mock_delete_object):
         handler({"granule": "thisiswronggranuleid,obviouslynotagranuleid"}, {})
         mock_list_objects.assert_not_called()
         mock_delete_object.assert_not_called()
+
+
+def test_no_granules_found_skips(mock_delete_object, capsys):
+    """Ensure we skip if no granules are found on S3
+
+    Ref: https://github.com/NASA-IMPACT/hls_development/issues/342
+    """
+    from lambda_functions.cleanup_sentinel2_granules import handler, s3
+
+    with (
+        patch.object(
+            s3,
+            "list_objects_v2",
+            return_value={},
+        ) as mock_list_objects,
+    ):
+        handler({"granule": "one12345"}, {})
+        mock_list_objects.assert_called()
+        mock_delete_object.assert_not_called()
+
+    captured = capsys.readouterr()
+    assert "Found 0 granule zip files for prefix" in captured.out