← full-stack-fastapi-template / backend/app/backend_pre_start.py
| 1 | import logging |
| 2 | |
| 3 | from sqlalchemy import Engine |
| 4 | from sqlmodel import Session, select |
| 5 | from tenacity import after_log, before_log, retry, stop_after_attempt, wait_fixed |
| 6 | |
| 7 | from app.core.db import engine |
| 8 | |
| 9 | logging.basicConfig(level=logging.INFO) |
| 10 | logger = logging.getLogger(__name__) |
| 11 | |
| 12 | max_tries = 60 * 5 # 5 minutes |
| 13 | wait_seconds = 1 |
| 14 | |
| 15 | |
| 16 | @retry( |
| 17 | stop=stop_after_attempt(max_tries), |
| 18 | wait=wait_fixed(wait_seconds), |
| 19 | before=before_log(logger, logging.INFO), |
| 20 | after=after_log(logger, logging.WARN), |
| 21 | ) |
| 22 | def init(db_engine: Engine) -> None: |
| 23 | try: |
| 24 | with Session(db_engine) as session: |
| 25 | # Try to create session to check if DB is awake |
| 26 | session.exec(select(1)) |
| 27 | except Exception as e: |
| 28 | logger.error(e) |
| 29 | raise e |
| 30 | |
| 31 | |
| 32 | def main() -> None: |
| 33 | logger.info("Initializing service") |
| 34 | init(engine) |
| 35 | logger.info("Service finished initializing") |
| 36 | |
| 37 | |
| 38 | if __name__ == "__main__": |
| 39 | main() |
| 40 |