From 8a16dc428b3cca823021c2df0e3c03b2b8606b29 Mon Sep 17 00:00:00 2001
From: Konstantin Malanchev <malanchev@cmu.edu>
Date: Tue, 20 Jan 2026 11:14:21 -0800
Subject: [PATCH] add fetch_dp2_ccd_visit.py

---
 scripts/fetch_dp2_ccd_visit.py | 72 ++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100755 scripts/fetch_dp2_ccd_visit.py

diff --git a/scripts/fetch_dp2_ccd_visit.py b/scripts/fetch_dp2_ccd_visit.py
new file mode 100755
index 0000000..a74fb1c
--- /dev/null
+++ b/scripts/fetch_dp2_ccd_visit.py
@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+
+import argparse
+from pathlib import Path
+from shutil import copyfileobj
+
+
+def parse_args(argv=None):
+    """Parse command-line arguments."""
+    parser = argparse.ArgumentParser(
+        description="Fetch DP2 CCD visit parquet file from the Butler repository. "
+        "Requires LSST stack environment."
+    )
+    parser.add_argument(
+        "--run",
+        type=str,
+        required=True,
+        help="The run identifier for the data (e.g., '20250417_20250921').",
+    )
+    parser.add_argument(
+        "--version",
+        type=str,
+        required=True,
+        help="The version (e.g., for weekly, 'w_2025_49').",
+    )
+    parser.add_argument(
+        "--collection",
+        type=str,
+        required=True,
+        help="The collection name (e.g., 'DM-53545').",
+    )
+    parser.add_argument(
+        "--config",
+        type=str,
+        default="dp2_prep",
+        help="The Butler configuration to use (default: 'dp2_prep').",
+    )
+    parser.add_argument(
+        "--destination",
+        type=Path,
+        default=Path(__file__).parent.parent / "data" / "dp2" / "public_parquet" / "ccd_visit.parquet",
+        help="The local path to save the parquet file "
+        "(default: 'data/dp2/public_parquet/ccd_visit.parquet').",
+    )
+    return parser.parse_args(argv)
+
+
+def get_uri(*, run, version, collection, config, **_kwargs):
+    """Get LSST URI object for the visit_detector_table parquet file."""
+    from lsst.daf.butler import Butler
+
+    collections = f"LSSTCam/runs/DRP/{run}/{version}/{collection}"
+    butler = Butler(config, collections=collections)
+    uri = butler.getURI("visit_detector_table", dataId={"instrument": "LSSTCam"})
+    return uri
+
+
+def copy_to_local(uri, local_path):
+    """Copy file from LSST URI to local path."""
+    with uri.open("rb") as src, local_path.open("wb") as dest:
+        copyfileobj(src, dest)
+
+
+def main(argv=None):
+    """Fetch DP2 CCD visit parquet file and save it locally."""
+    arg = parse_args(argv)
+    uri = get_uri(**vars(arg))
+    copy_to_local(uri, arg.destination)
+
+
+if __name__ == "__main__":
+    main()