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Contents
require 'digest/sha1'
require_relative 'rate_limiting/redis_script'
module Bearcat
module RateLimiting
LEAK_RATE = 10
GUESS_COST = 60
MAXIMUM = 600
class RateLimiter
attr_reader :namespace
def initialize(namespace: "bearcat", **kwargs)
@namespace = namespace
@params = kwargs
end
def apply(key, guess: GUESS_COST, on_sleep: nil, max_sleep: 15)
current = increment("#{key}", 0, guess)
cost = guess
remaining = MAXIMUM - current[:count]
if remaining < 0
tts = -remaining / LEAK_RATE
tts = [tts, max_sleep].min if max_sleep
on_sleep.call(tts) if on_sleep
sleep tts
end
cost = yield
ensure
increment(key, (cost || 0), -guess)
end
end
class RedisLimiter < RateLimiter
INCR = RedisScript.new(Pathname.new(__FILE__) + "../rate_limiting/increment_bucket.lua")
def increment(key, amount, pending_amount = 0)
ts = Time.now.to_f
redis do |r|
actual, timestamp = INCR.call(r, ["#{key}|reported"], [amount, ts, LEAK_RATE, MAXIMUM + 300])
{
count: actual.to_f,
timestamp: timestamp.to_f,
}
end
end
def checkin_known(key, remaining_time)
redis do |r|
r.mapped_hmset("#{key}|reported", {
count: MAXIMUM + 200 - remaining_time,
timestamp: Time.now.to_f,
})
end
end
def redis(&blk)
# TODO Add bearcat-native ConnectionPool instead of relying on application or Sidekiq to do so
if @params[:redis]
@params[:redis].call(blk)
else
::Sidekiq.redis(&blk)
end
end
end
end
end
Version data entries
10 entries across 10 versions & 1 rubygems