scripts/jsonl_to_parquet.py

#!/usr/bin/env python3
"""
Convert a JSONL file (records per line) to Parquet with a stable schema.

Usage:
  python scripts/jsonl_to_parquet.py manifests/preview.jsonl manifests/preview.parquet
  python scripts/jsonl_to_parquet.py manifests/dev.jsonl manifests/dev.parquet

Requires: pandas + pyarrow
"""
import argparse
import json
from pathlib import Path

import pandas as pd


def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("src", type=Path)
    ap.add_argument("dst", type=Path)
    args = ap.parse_args()

    records = []
    with args.src.open("r", encoding="utf-8") as f:
        for line in f:
            if not line.strip():
                continue
            records.append(json.loads(line))

    # Use pandas to write parquet; let pyarrow infer nested lists
    df = pd.DataFrame.from_records(records)
    args.dst.parent.mkdir(parents=True, exist_ok=True)
    df.to_parquet(args.dst, index=False)
    print(f"Wrote {args.dst}")


if __name__ == "__main__":
    main()