08/04/2023, 12:55 AM
I'm trying to limit concurrency at the task level to keep from hitting an api at a rate that exceeds their limit. I'm invoking the task with .sumbit(), and then calling .result() - and I have the task tagged and used the command line for setting the concurrency limit, but when I run the flow the concurrency limit is not enforced. Am I missing something? Is there a simple example somewhere that demonstrates this common scenario?
For example, I'm not able to get this example to demonstrate the concurrency limit.
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import httpx
from datetime import timedelta
from prefect import flow, task, get_run_logger
from prefect.tasks import task_input_hash

@task(tags=['mytest'], cache_key_fn=task_input_hash, cache_expiration=timedelta(hours=1))
def get_url(url: str, params: dict = None):
    response = httpx.get(url, params=params)
    return response.json()

def get_open_issues(repo_name: str, open_issues_count: int, per_page: int = 100):
    issues = []
    pages = range(1, -(open_issues_count // -per_page) + 1)
    for page in pages:
                params={"page": page, "per_page": per_page, "state": "open"},
    return [i for p in issues for i in p.result()]

@flow(retries=3, retry_delay_seconds=5)
def get_repo_info(
    repo_name: str = "PrefectHQ/prefect"
    repo = get_url(f"<{repo_name}>")
    issues = get_open_issues(repo_name, repo["open_issues_count"])
    issues_per_user = len(issues) / len(set([i["user"]["id"] for i in issues]))
    logger = get_run_logger()
    <|>(f"PrefectHQ/prefect repository statistics 🤓:")
    <|>(f"Stars 🌠 : {repo['stargazers_count']}")
    <|>(f"Forks 🍴 : {repo['forks_count']}")
    <|>(f"Average open issues per user 💌 : {issues_per_user:.2f}")

if __name__ == "__main__":
on the command line I set the limit with:
prefect concurrency-limit create mytest 2
then I run the flow with:
python3 ./templates/