Sean Conroy
05/25/2023, 11:35 PMFailed("Flow run encountered an exception. PrefectHTTPStatusError: Client error '429 Too Many Requests'"
What is the limit? How can I solve this?Marvin
05/25/2023, 11:37 PMSean Conroy
05/25/2023, 11:38 PMMarvin
05/25/2023, 11:40 PMmax_concurrent
parameter of the Semaphore
class. A semaphore is a synchronization primitive that can be used to limit the number of concurrent tasks running at the same time.
Here's an example of how to use a semaphore to limit concurrency:
python
from prefect import Flow, task
from prefect.executors import LocalExecutor
from prefect.schedules import IntervalSchedule
from prefect.triggers import any_successful
from prefect.utilities.tasks import Semaphore
# Create a semaphore with a concurrency limit of 2
semaphore = Semaphore(max_concurrent=2)
@task
def task_a():
print("Task A")
@task
def task_b():
print("Task B")
@task
def task_c():
print("Task C")
with Flow("concurrency_example") as flow:
a = task_a()
b = task_b()
c = task_c()
# Acquire the semaphore before running the tasks
semaphore.acquire(a)
semaphore.acquire(b)
semaphore.acquire(c)
# Release the semaphore after the tasks are completed
semaphore.release(a)
semaphore.release(b)
semaphore.release(c)
# Run the flow
flow.run(executor=LocalExecutor())
In this example, the Semaphore
class is used to limit the concurrency of tasks A, B, and C to a maximum of 2 concurrent tasks. The tasks will acquire the semaphore before running and release it after completion.
Remember, it's not the size of your semaphore that matters; it's how you use it.Sean Conroy
05/25/2023, 11:42 PMMarvin
05/25/2023, 11:42 PMprefect concurrency-limit [command] [arguments]
details here (https://docs.prefect.io/latest/concepts/tasks/?h=concu#cli)
you can check out the work queue level concurrency rate limit docs (https://docs.prefect.io/latest/concepts/work-pools/?h=concurrency#work-pool-concurrency)
or task-level concurrency here (https://docs.prefect.io/latest/concepts/tasks/?h=concurr#task-run-concurrency-limits)Nate
05/26/2023, 1:48 AMAnthony Head
05/26/2023, 2:05 AM