mirror of https://github.com/zulip/zulip.git
227 lines
7.8 KiB
Python
227 lines
7.8 KiB
Python
from __future__ import absolute_import
|
|
|
|
from six import text_type
|
|
from typing import Any, Iterator, Tuple
|
|
|
|
from django.conf import settings
|
|
from zerver.lib.redis_utils import get_redis_client
|
|
from six.moves import zip
|
|
|
|
from zerver.models import UserProfile
|
|
|
|
import redis
|
|
import time
|
|
import logging
|
|
|
|
# Implement a rate-limiting scheme inspired by the one described here, but heavily modified
|
|
# http://blog.domaintools.com/2013/04/rate-limiting-with-redis/
|
|
|
|
client = get_redis_client()
|
|
rules = settings.RATE_LIMITING_RULES # type: List[Tuple[int, int]]
|
|
def _rules_for_user(user):
|
|
# type: (UserProfile) -> List[Tuple[int, int]]
|
|
if user.rate_limits != "":
|
|
result = [] # type: List[Tuple[int, int]]
|
|
for limit in user.rate_limits.split(','):
|
|
(seconds, requests) = limit.split(':', 2)
|
|
result.append((int(seconds), int(requests)))
|
|
return result
|
|
return rules
|
|
|
|
def redis_key(user, domain):
|
|
# type: (UserProfile, text_type) -> List[text_type]
|
|
"""Return the redis keys for this user"""
|
|
return ["ratelimit:%s:%s:%s:%s" % (type(user), user.id, domain, keytype) for keytype in ['list', 'zset', 'block']]
|
|
|
|
def max_api_calls(user):
|
|
# type: (UserProfile) -> int
|
|
"Returns the API rate limit for the highest limit"
|
|
return _rules_for_user(user)[-1][1]
|
|
|
|
def max_api_window(user):
|
|
# type: (UserProfile) -> int
|
|
"Returns the API time window for the highest limit"
|
|
return _rules_for_user(user)[-1][0]
|
|
|
|
def add_ratelimit_rule(range_seconds, num_requests):
|
|
# type: (int , int) -> None
|
|
"Add a rate-limiting rule to the ratelimiter"
|
|
global rules
|
|
|
|
rules.append((range_seconds, num_requests))
|
|
rules.sort(key=lambda x: x[0])
|
|
|
|
def remove_ratelimit_rule(range_seconds, num_requests):
|
|
# type: (int , int) -> None
|
|
global rules
|
|
rules = [x for x in rules if x[0] != range_seconds and x[1] != num_requests]
|
|
|
|
def block_user(user, seconds, domain='all'):
|
|
# type: (UserProfile, int, text_type) -> None
|
|
"Manually blocks a user id for the desired number of seconds"
|
|
_, _, blocking_key = redis_key(user, domain)
|
|
with client.pipeline() as pipe:
|
|
pipe.set(blocking_key, 1)
|
|
pipe.expire(blocking_key, seconds)
|
|
pipe.execute()
|
|
|
|
def unblock_user(user, domain='all'):
|
|
# type: (UserProfile, str) -> None
|
|
_, _, blocking_key = redis_key(user, domain)
|
|
client.delete(blocking_key)
|
|
|
|
def clear_user_history(user, domain='all'):
|
|
# type: (UserProfile, text_type) -> None
|
|
'''
|
|
This is only used by test code now, where it's very helpful in
|
|
allowing us to run tests quickly, by giving a user a clean slate.
|
|
'''
|
|
for key in redis_key(user, domain):
|
|
client.delete(key)
|
|
|
|
def _get_api_calls_left(user, domain, range_seconds, max_calls):
|
|
# type: (UserProfile, text_type, int, int) -> Tuple[int, float]
|
|
list_key, set_key, _ = redis_key(user, domain)
|
|
# Count the number of values in our sorted set
|
|
# that are between now and the cutoff
|
|
now = time.time()
|
|
boundary = now - range_seconds
|
|
|
|
with client.pipeline() as pipe:
|
|
# Count how many API calls in our range have already been made
|
|
pipe.zcount(set_key, boundary, now)
|
|
# Get the newest call so we can calculate when the ratelimit
|
|
# will reset to 0
|
|
pipe.lindex(list_key, 0)
|
|
|
|
results = pipe.execute()
|
|
|
|
count = results[0]
|
|
newest_call = results[1]
|
|
|
|
calls_left = max_calls - count
|
|
if newest_call is not None:
|
|
time_reset = now + (range_seconds - (now - float(newest_call)))
|
|
else:
|
|
time_reset = now
|
|
|
|
return calls_left, time_reset
|
|
|
|
def api_calls_left(user, domain='all'):
|
|
# type: (UserProfile, text_type) -> Tuple[int, float]
|
|
"""Returns how many API calls in this range this client has, as well as when
|
|
the rate-limit will be reset to 0"""
|
|
max_window = _rules_for_user(user)[-1][0]
|
|
max_calls = _rules_for_user(user)[-1][1]
|
|
return _get_api_calls_left(user, domain, max_window, max_calls)
|
|
|
|
def is_ratelimited(user, domain='all'):
|
|
# type: (UserProfile, text_type) -> Tuple[bool, float]
|
|
"Returns a tuple of (rate_limited, time_till_free)"
|
|
list_key, set_key, blocking_key = redis_key(user, domain)
|
|
|
|
rules = _rules_for_user(user)
|
|
|
|
if len(rules) == 0:
|
|
return False, 0.0
|
|
|
|
# Go through the rules from shortest to longest,
|
|
# seeing if this user has violated any of them. First
|
|
# get the timestamps for each nth items
|
|
with client.pipeline() as pipe:
|
|
for _, request_count in rules:
|
|
pipe.lindex(list_key, request_count - 1) # 0-indexed list
|
|
|
|
# Get blocking info
|
|
pipe.get(blocking_key)
|
|
pipe.ttl(blocking_key)
|
|
|
|
rule_timestamps = pipe.execute()
|
|
|
|
# Check if there is a manual block on this API key
|
|
blocking_ttl = rule_timestamps.pop()
|
|
key_blocked = rule_timestamps.pop()
|
|
|
|
if key_blocked is not None:
|
|
# We are manually blocked. Report for how much longer we will be
|
|
if blocking_ttl is None:
|
|
blocking_ttl = 0.5
|
|
else:
|
|
blocking_ttl = int(blocking_ttl)
|
|
return True, blocking_ttl
|
|
|
|
now = time.time()
|
|
for timestamp, (range_seconds, num_requests) in zip(rule_timestamps, rules):
|
|
# Check if the nth timestamp is newer than the associated rule. If so,
|
|
# it means we've hit our limit for this rule
|
|
if timestamp is None:
|
|
continue
|
|
|
|
timestamp = float(timestamp)
|
|
boundary = timestamp + range_seconds
|
|
if boundary > now:
|
|
free = boundary - now
|
|
return True, free
|
|
|
|
# No api calls recorded yet
|
|
return False, 0.0
|
|
|
|
def incr_ratelimit(user, domain='all'):
|
|
# type: (UserProfile, text_type) -> None
|
|
"""Increases the rate-limit for the specified user"""
|
|
list_key, set_key, _ = redis_key(user, domain)
|
|
now = time.time()
|
|
|
|
# If we have no rules, we don't store anything
|
|
if len(rules) == 0:
|
|
return
|
|
|
|
# Start redis transaction
|
|
with client.pipeline() as pipe:
|
|
count = 0
|
|
while True:
|
|
try:
|
|
# To avoid a race condition between getting the element we might trim from our list
|
|
# and removing it from our associated set, we abort this whole transaction if
|
|
# another agent manages to change our list out from under us
|
|
# When watching a value, the pipeline is set to Immediate mode
|
|
pipe.watch(list_key)
|
|
|
|
# Get the last elem that we'll trim (so we can remove it from our sorted set)
|
|
last_val = pipe.lindex(list_key, max_api_calls(user) - 1)
|
|
|
|
# Restart buffered execution
|
|
pipe.multi()
|
|
|
|
# Add this timestamp to our list
|
|
pipe.lpush(list_key, now)
|
|
|
|
# Trim our list to the oldest rule we have
|
|
pipe.ltrim(list_key, 0, max_api_calls(user) - 1)
|
|
|
|
# Add our new value to the sorted set that we keep
|
|
# We need to put the score and val both as timestamp,
|
|
# as we sort by score but remove by value
|
|
pipe.zadd(set_key, now, now)
|
|
|
|
# Remove the trimmed value from our sorted set, if there was one
|
|
if last_val is not None:
|
|
pipe.zrem(set_key, last_val)
|
|
|
|
# Set the TTL for our keys as well
|
|
api_window = max_api_window(user)
|
|
pipe.expire(list_key, api_window)
|
|
pipe.expire(set_key, api_window)
|
|
|
|
pipe.execute()
|
|
|
|
# If no exception was raised in the execution, there were no transaction conflicts
|
|
break
|
|
except redis.WatchError:
|
|
if count > 10:
|
|
logging.error("Failed to complete incr_ratelimit transaction without interference 10 times in a row! Aborting rate-limit increment")
|
|
break
|
|
count += 1
|
|
|
|
continue
|