import grequests

urls = [
 "https://www.baidu.com",
 "https://www.google.com"
]
requests = [
 grequests.get(url)
 for url in urls
] * 1000

rate = 20 # 表示 20 请求/秒

from time import sleep

req_groups = [
 requests[i: i+rate]
 for i in range(0, len(requests), rate)
]

ret = []
for req_group in req_groups:
 ret += grequests.map(req_group)
 sleep(1)

print(ret)

from time import time

class Throttle:
 def __init__(self, rate):
  self.rate = rate
  self.tokens = 0
  self.last = 0
 
 def consume(self, amount=1):
  now = time()
  
  if self.last == 0:
   self.last = now
  
  elapsed = now - self.last

  if int(elapsed * self.rate):
   self.tokens += int(elapsed * self.rate)
   self.last = now
  
  self.tokens = (
   self.rate
   if self.tokens > self.rate
   else self.tokens
  )
  
  if self.tokens >= amount:
   self.tokens -= amount
  else:
   amount = 0
  
  return amount

throttle = Throttle(rate)

req_groups = [
 requests[i: i+rate]
 for i in range(0, len(requests), rate)
]

ret = []
for req_group in req_groups:
 ret += grequests.map(req_group)
 while throttle.consume():
  pass # 阻塞

print(ret)

pip install grequests-throttle

import grequests_throttle as gt

ret = gt.map(requests, rate=rate)
print(ret)