88 lines
2.8 KiB
Python
88 lines
2.8 KiB
Python
"""LangGraph checkpoint support for resumable analysis runs.
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Per-ticker SQLite databases so concurrent tickers don't contend.
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"""
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from __future__ import annotations
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import hashlib
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import sqlite3
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from contextlib import contextmanager
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from pathlib import Path
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from typing import Generator
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from langgraph.checkpoint.sqlite import SqliteSaver
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def _db_path(data_dir: str | Path, ticker: str) -> Path:
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"""Return the SQLite checkpoint DB path for a ticker."""
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p = Path(data_dir) / "checkpoints"
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p.mkdir(parents=True, exist_ok=True)
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return p / f"{ticker.upper()}.db"
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def thread_id(ticker: str, date: str) -> str:
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"""Deterministic thread ID for a ticker+date pair."""
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return hashlib.sha256(f"{ticker.upper()}:{date}".encode()).hexdigest()[:16]
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@contextmanager
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def get_checkpointer(data_dir: str | Path, ticker: str) -> Generator[SqliteSaver, None, None]:
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"""Context manager yielding a SqliteSaver backed by a per-ticker DB."""
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db = _db_path(data_dir, ticker)
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conn = sqlite3.connect(str(db), check_same_thread=False)
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try:
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saver = SqliteSaver(conn)
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saver.setup()
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yield saver
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finally:
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conn.close()
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def has_checkpoint(data_dir: str | Path, ticker: str, date: str) -> bool:
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"""Check whether a resumable checkpoint exists for ticker+date."""
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return checkpoint_step(data_dir, ticker, date) is not None
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def checkpoint_step(data_dir: str | Path, ticker: str, date: str) -> int | None:
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"""Return the step number of the latest checkpoint, or None if none exists."""
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db = _db_path(data_dir, ticker)
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if not db.exists():
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return None
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tid = thread_id(ticker, date)
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with get_checkpointer(data_dir, ticker) as saver:
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config = {"configurable": {"thread_id": tid}}
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cp = saver.get_tuple(config)
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if cp is None:
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return None
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return cp.metadata.get("step")
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def clear_all_checkpoints(data_dir: str | Path) -> int:
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"""Remove all checkpoint DBs. Returns number of files deleted."""
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cp_dir = Path(data_dir) / "checkpoints"
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if not cp_dir.exists():
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return 0
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dbs = list(cp_dir.glob("*.db"))
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for db in dbs:
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db.unlink()
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return len(dbs)
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def clear_checkpoint(data_dir: str | Path, ticker: str, date: str) -> None:
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"""Remove checkpoint for a specific ticker+date (delete the whole DB if it's the only thread)."""
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db = _db_path(data_dir, ticker)
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if not db.exists():
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return
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tid = thread_id(ticker, date)
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conn = sqlite3.connect(str(db))
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try:
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# Delete writes and checkpoints for this thread
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for table in ("writes", "checkpoints"):
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conn.execute(f"DELETE FROM {table} WHERE thread_id = ?", (tid,))
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conn.commit()
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except sqlite3.OperationalError:
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pass # table doesn't exist yet
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finally:
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conn.close()
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