| import fcntl | |
| import hashlib | |
| import json | |
| import sqlite3 | |
| from contextlib import contextmanager | |
| from pathlib import Path | |
| def fingerprint(value): | |
| return hashlib.sha256(json.dumps(value, sort_keys=True).encode()).hexdigest() | |
| def locked_state(directory): | |
| directory = Path(directory) | |
| directory.mkdir(parents=True, exist_ok=True) | |
| with (directory / 'worker.lock').open('a') as lock: | |
| try: | |
| fcntl.flock(lock, fcntl.LOCK_EX | fcntl.LOCK_NB) | |
| except BlockingIOError: | |
| raise RuntimeError('Another vector worker is using this state volume.') from None | |
| with sqlite3.connect(directory / 'cache.sqlite') as db: | |
| db.execute('CREATE TABLE IF NOT EXISTS vectors (key TEXT PRIMARY KEY, value TEXT NOT NULL)') | |
| yield db | |
| def cached_vectors(db, key, produce): | |
| row = db.execute('SELECT value FROM vectors WHERE key=?', (key,)).fetchone() | |
| if row: | |
| return json.loads(row[0]) | |
| vectors = produce() | |
| db.execute('INSERT INTO vectors VALUES (?,?)', (key, json.dumps(vectors))) | |
| db.commit() | |
| return vectors | |