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feat: rate limit control (#217)
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hank9999 committed Nov 7, 2023
1 parent 25d26b4 commit 3002faf
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Showing 4 changed files with 126 additions and 7 deletions.
1 change: 1 addition & 0 deletions khl/__init__.py
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
from .cert import Cert
from .receiver import Receiver, WebhookReceiver, WebsocketReceiver
from .requester import HTTPRequester
from .ratelimiter import RateLimiter
from .gateway import Gateway, Requestable
from .client import Client

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12 changes: 7 additions & 5 deletions khl/bot/bot.py
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
from typing import Dict, Callable, List, Optional, Union, Coroutine, IO

from .. import AsyncRunnable # interfaces
from .. import Cert, HTTPRequester, WebhookReceiver, WebsocketReceiver, Gateway, Client # net related
from .. import Cert, HTTPRequester, RateLimiter, WebhookReceiver, WebsocketReceiver, Gateway, Client # net related
from .. import MessageTypes, EventTypes, SlowModeTypes, SoftwareTypes # types
from .. import User, Channel, PublicChannel, Guild, Event, Message # concepts
from ..command import CommandManager
Expand Down Expand Up @@ -49,7 +49,8 @@ def __init__(self,
out: HTTPRequester = None,
compress: bool = True,
port=5000,
route='/khl-wh'):
route='/khl-wh',
ratelimiter: Optional[RateLimiter] = RateLimiter(start=80)):
"""
The most common usage: ``Bot(token='xxxxxx')``
Expand All @@ -66,7 +67,7 @@ def __init__(self,
if not token and not cert:
raise ValueError('require token or cert')

self._init_client(cert or Cert(token=token), client, gate, out, compress, port, route)
self._init_client(cert or Cert(token=token), client, gate, out, compress, port, route, ratelimiter)
self._register_client_handler()

self.command = CommandManager()
Expand All @@ -78,7 +79,8 @@ def __init__(self,
self._startup_index = []
self._shutdown_index = []

def _init_client(self, cert: Cert, client: Client, gate: Gateway, out: HTTPRequester, compress: bool, port, route):
def _init_client(self, cert: Cert, client: Client, gate: Gateway, out: HTTPRequester, compress: bool, port, route,
ratelimiter):
"""
construct self.client from args.
Expand All @@ -102,7 +104,7 @@ def _init_client(self, cert: Cert, client: Client, gate: Gateway, out: HTTPReque
return

# client and gate not in args, build them
_out = out if out else HTTPRequester(cert)
_out = out if out else HTTPRequester(cert, ratelimiter)
if cert.type == Cert.Types.WEBSOCKET:
_in = WebsocketReceiver(cert, compress)
elif cert.type == Cert.Types.WEBHOOK:
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106 changes: 106 additions & 0 deletions khl/ratelimiter.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,106 @@
import asyncio
import logging
from typing import Dict

log = logging.getLogger(__name__)


class RateLimiter:
"""rate limit control
@param start: when the remain reach this number, start ratelimit
"""

def __init__(self, start: int = 120):
self._ratelimit_info: Dict[str, RateLimiter.RateLimitData] = {}
self._api_bucket_mapping: Dict[str, str] = {}
self._lock = asyncio.Lock()
self._start = start

async def wait_for_rate(self, route):
"""get and wait delay"""

bucket = await self.get_bucket(route)
delay = await self.get_delay(bucket)
log.debug(f'ratelimiter: {route} req bucket: {bucket} delay: {delay: .3f}s')
await asyncio.sleep(delay)

async def update(self, route, headers):
"""get values and update ratelimit information"""

if 'X-Rate-Limit-Limit' in headers:
bucket, remaining, reset = self.extract_xrate_header(headers)
await self.push_api_bucket_mapping(route, bucket)
await self.update_ratelimit(bucket, remaining, reset)
log.debug(f'ratelimiter: {route} rsp ratelimit: bucket: {bucket} remaining: {remaining} reset: {reset}s')

async def push_api_bucket_mapping(self, api: str, bucket: str):
"""
when finished request, associate bucket that api returned with api route
to avoid that bucket and api router are not the same
"""

api = api.lower()
bucket = bucket.lower()

async with self._lock:
if api not in self._api_bucket_mapping:
self._api_bucket_mapping[api] = bucket

async def get_bucket(self, api: str):
"""get bucket name by api route"""

api = api.lower()

async with self._lock:
if api not in self._api_bucket_mapping:
return api

return self._api_bucket_mapping[api]

async def update_ratelimit(self, bucket: str, remaining: int, reset: int):
"""update rate limit info"""

bucket = bucket.lower()
async with self._lock:
if bucket not in self._ratelimit_info:
self._ratelimit_info[bucket] = self.RateLimitData(remaining, reset)
else:
self._ratelimit_info[bucket].remaining = remaining
self._ratelimit_info[bucket].reset = reset

async def get_delay(self, bucket: str) -> float:
"""get request delay time, seconds"""

bucket = bucket.lower()
async with self._lock:
if bucket not in self._ratelimit_info:
return 0

if self._ratelimit_info[bucket].reset == 0:
return 0

if self._ratelimit_info[bucket].remaining == 0:
return self._ratelimit_info[bucket].reset

if self._ratelimit_info[bucket].remaining > self._start:
return 0

delay = self._ratelimit_info[bucket].reset / self._ratelimit_info[bucket].remaining

return delay

@staticmethod
def extract_xrate_header(headers):
"""get bucket, remaining, reset values from headers"""

bucket = headers['X-Rate-Limit-Bucket']
remaining = int(headers['X-Rate-Limit-Remaining'])
reset = int(headers['X-Rate-Limit-Reset'])
return bucket, remaining, reset

class RateLimitData:
"""to save single bucket rate limit"""

def __init__(self, remaining: int = 120, reset: int = 0):
self.remaining = remaining
self.reset = reset
14 changes: 12 additions & 2 deletions khl/requester.py
Original file line number Diff line number Diff line change
@@ -1,9 +1,10 @@
import asyncio
import logging
from typing import Union, List
from typing import Union, List, Optional

from aiohttp import ClientSession

from .ratelimiter import RateLimiter
from .api import _Req
from .cert import Cert

Expand All @@ -15,9 +16,10 @@
class HTTPRequester:
"""wrap raw requests, handle boilerplate param filling works"""

def __init__(self, cert: Cert):
def __init__(self, cert: Cert, ratelimiter: Optional[RateLimiter]):
self._cert = cert
self._cs: Union[ClientSession, None] = None
self._ratelimiter = ratelimiter

def __del__(self):
if self._cs is not None:
Expand All @@ -29,6 +31,10 @@ async def request(self, method: str, route: str, **params) -> Union[dict, list,
params['headers'] = headers

log.debug(f'{method} {route}: req: {params}') # token is excluded

if self._ratelimiter is not None:
await self._ratelimiter.wait_for_rate(route)

headers['Authorization'] = f'Bot {self._cert.token}'
if self._cs is None: # lazy init
self._cs = ClientSession()
Expand All @@ -40,6 +46,10 @@ async def request(self, method: str, route: str, **params) -> Union[dict, list,
rsp = rsp['data']
else:
rsp = await res.read()

if self._ratelimiter is not None:
await self._ratelimiter.update(route, res.headers)

log.debug(f'{method} {route}: rsp: {rsp}')
return rsp

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