您需要创建自己的速率限制器,因为 Celery 的速率限制仅适用于每个工作人员,并且“无法按您的预期工作”。
我个人发现在尝试从另一个任务中添加新任务时它会完全崩溃。
我认为速率限制的要求范围太广,并且取决于应用程序本身,因此 Celery 的实现故意过于简单。
这是我使用Celery + Django + Redis 创建的示例。
基本上,它为您的App.Task 类添加了一个方便的方法,它将跟踪您在Redis 中的任务执行率。如果太高,任务会在以后Retry。
此示例使用发送 SMTP 消息作为示例,但可以轻松替换为 API 调用。
算法灵感来自 Figma https://www.figma.com/blog/an-alternative-approach-to-rate-limiting/
https://gist.github.com/Vigrond/2bbea9be6413415e5479998e79a1b11a
# Rate limiting with Celery + Django + Redis
# Multiple Fixed Windows Algorithm inspired by Figma https://www.figma.com/blog/an-alternative-approach-to-rate-limiting/
# and Celery's sometimes ambiguous, vague, and one-paragraph documentation
#
# Celery's Task is subclassed and the is_rate_okay function is added
# celery.py or however your App is implemented in Django
import os
import math
import time
from celery import Celery, Task
from django_redis import get_redis_connection
from django.conf import settings
from django.utils import timezone
app = Celery('your_app')
# Get Redis connection from our Django 'default' cache setting
redis_conn = get_redis_connection("default")
# We subclass the Celery Task
class YourAppTask(Task):
def is_rate_okay(self, times=30, per=60):
"""
Checks to see if this task is hitting our defined rate limit too much.
This example sets a rate limit of 30/minute.
times (int): The "30" in "30 times per 60 seconds".
per (int): The "60" in "30 times per 60 seconds".
The Redis structure we create is a Hash of timestamp keys with counter values
{
'1560649027.515933': '2', // unlikely to have more than 1
'1560649352.462433': '1',
}
The Redis key is expired after the amount of 'per' has elapsed.
The algorithm totals the counters and checks against 'limit'.
This algorithm currently does not implement the "leniency" described
at the bottom of the figma article referenced at the top of this code.
This is left up to you and depends on application.
Returns True if under the limit, otherwise False.
"""
# Get a timestamp accurate to the microsecond
timestamp = timezone.now().timestamp()
# Set our Redis key to our task name
key = f"rate:{self.name}"
# Create a pipeline to execute redis code atomically
pipe = redis_conn.pipeline()
# Increment our current task hit in the Redis hash
pipe.hincrby(key, timestamp)
# Grab the current expiration of our task key
pipe.ttl(key)
# Grab all of our task hits in our current frame (of 60 seconds)
pipe.hvals(key)
# This returns a list of our command results. [current task hits, expiration, list of all task hits,]
result = pipe.execute()
# If our expiration is not set, set it. This is not part of the atomicity of the pipeline above.
if result[1] < 0:
redis_conn.expire(key, per)
# We must convert byte to int before adding up the counters and comparing to our limit
if sum([int(count) for count in result[2]]) <= times:
return True
else:
return False
app.Task = YourAppTask
app.config_from_object('django.conf:settings', namespace='CELERY')
app.autodiscover_tasks()
...
# SMTP Example
import random
from YourApp.celery import app
from django.core.mail import EmailMessage
# We set infinite max_retries so backlogged email tasks do not disappear
@app.task(name='smtp.send-email', max_retries=None, bind=True)
def send_email(self, to_address):
if not self.is_rate_okay():
# We implement a random countdown between 30 and 60 seconds
# so tasks don't come flooding back at the same time
raise self.retry(countdown=random.randint(30, 60))
message = EmailMessage(
'Hello',
'Body goes here',
'from@yourdomain.com',
[to_address],
)
message.send()