Complete with best practices, useful tools, and standards implemented by professional Python developers, this fourth edition has been extensively updated. Become familiar with the latest Python improvements, syntax elements, and interesting tools to boost your development efficiency.
# インストール
poetry new advent_calendar_prefect
cd advent_calendar_prefect/advent_calendar_prefect
poetry add "prefect>=2.0.0a"
poetry shell
basic.pyとして保存します。
from prefect import flow, task
from typing import List
import httpx
@task(retries=3)
def get_stars(repo: str):
url = f"https://api.github.com/repos/{repo}"
count = httpx.get(url).json()["stargazers_count"]
print(f"{repo} has {count} stars!")
@flow(name="Github Stars")
def github_stars(repos: List[str]):
for repo in repos:
get_stars(repo)
# run the flow!
github_stars(["PrefectHQ/Prefect", "PrefectHQ/miter-design"])
実行
python basic2.py
07:48:04.506 | Beginning flow run 'merciful-unicorn' for flow 'Github Stars'...
07:48:04.506 | Starting executor `SequentialExecutor`...
07:48:04.731 | Submitting task run 'get_stars-e40861f0-0' to executor...
PrefectHQ/Prefect has 7906 stars!
07:48:05.229 | Task run 'get_stars-e40861f0-0' finished in state Completed(message=None, type=COMPLETED)
07:48:05.319 | Submitting task run 'get_stars-e40861f0-1' to executor...
PrefectHQ/miter-design has 12 stars!
07:48:05.796 | Task run 'get_stars-e40861f0-1' finished in state Completed(message=None, type=COMPLETED)
07:48:05.800 | Shutting down executor `SequentialExecutor`...
07:48:05.882 | Flow run 'merciful-unicorn' finished in state Completed(message='All states completed.', type=COMPLETED)
サーバを起動
prefect orion start
prefet_orion
サーバを起動する前に実行したFlowも登録されていることに注目です。
（~/.prefect/orion.dbに情報が保存されるようです）
エラー
常に起きるかは不明ですが、自分の場合以下のエラーがでました（抜粋）。
sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: flow
[SQL: INSERT INTO flow (id, created, updated, name, tags) VALUES (?, ?, ?, ?, ?) ON CONFLICT (name) DO NOTHING]
[parameters: ('cb63d353-0279-4e4c-adfd-5bb1254b88d7', '2021-12-06 22:33:35.319780', '2021-12-06 22:33:35.319804', 'my-favorite-function', '[]')]
(Background on this error at: https://sqlalche.me/e/14/e3q8)
