Files
py-libp2p/libp2p/pubsub/validation_throttler.py

315 lines
11 KiB
Python

from collections.abc import (
Callable,
)
from dataclasses import dataclass
from enum import Enum
import logging
from typing import (
NamedTuple,
cast,
)
import trio
from libp2p.custom_types import AsyncValidatorFn, ValidatorFn
from libp2p.peer.id import (
ID,
)
from .pb import (
rpc_pb2,
)
logger = logging.getLogger("libp2p.pubsub.validation")
class ValidationResult(Enum):
ACCEPT = "accept"
REJECT = "reject"
IGNORE = "ignore"
THROTTLED = "throttled"
@dataclass
class ValidationRequest:
"""Request for message validation"""
validators: list["TopicValidator"]
msg_forwarder: ID # peer ID
msg: rpc_pb2.Message # message object
result_callback: Callable[[ValidationResult, Exception | None], None]
class TopicValidator(NamedTuple):
topic: str
validator: ValidatorFn
is_async: bool
timeout: float | None = None
# Per-topic throttle semaphore
throttle_semaphore: trio.Semaphore | None = None
class ValidationThrottler:
"""Manages all validation throttling mechanisms"""
def __init__(
self,
queue_size: int = 32,
global_throttle_limit: int = 8192,
default_topic_throttle_limit: int = 1024,
worker_count: int | None = None,
):
# 1. Queue-level throttling - bounded memory channel
self._validation_send, self._validation_receive = trio.open_memory_channel[
ValidationRequest
](queue_size)
# 2. Global validation throttling - limits total concurrent async validations
self._global_throttle = trio.Semaphore(global_throttle_limit)
# 3. Per-topic throttling - each validator gets its own semaphore
self._default_topic_throttle_limit = default_topic_throttle_limit
# Worker management
# TODO: Find a better way to manage worker count
self._worker_count = worker_count or 4
self._running = False
async def start(self, nursery: trio.Nursery) -> None:
"""Start the validation workers"""
self._running = True
# Start validation worker tasks
for i in range(self._worker_count):
nursery.start_soon(self._validation_worker, f"worker-{i}")
async def stop(self) -> None:
"""Stop the validation system"""
self._running = False
await self._validation_send.aclose()
def create_topic_validator(
self,
topic: str,
validator: ValidatorFn,
is_async: bool,
timeout: float | None = None,
throttle_limit: int | None = None,
) -> TopicValidator:
"""Create a new topic validator with its own throttle"""
limit = throttle_limit or self._default_topic_throttle_limit
throttle_sem = trio.Semaphore(limit)
return TopicValidator(
topic=topic,
validator=validator,
is_async=is_async,
timeout=timeout,
throttle_semaphore=throttle_sem,
)
async def submit_validation(
self,
validators: list[TopicValidator],
msg_forwarder: ID,
msg: rpc_pb2.Message,
result_callback: Callable[[ValidationResult, Exception | None], None],
) -> bool:
"""
Submit a message for validation.
Returns True if queued successfully, False if queue is full (throttled).
"""
if not self._running:
result_callback(
ValidationResult.REJECT, Exception("Validation system not running")
)
return False
request = ValidationRequest(
validators=validators,
msg_forwarder=msg_forwarder,
msg=msg,
result_callback=result_callback,
)
try:
# This will raise trio.WouldBlock if queue is full
self._validation_send.send_nowait(request)
return True
except trio.WouldBlock:
# Queue-level throttling: drop the message
logger.debug(
"Validation queue full, dropping message from %s", msg_forwarder
)
result_callback(
ValidationResult.THROTTLED, Exception("Validation queue full")
)
return False
async def _validation_worker(self, worker_id: str) -> None:
"""Worker that processes validation requests"""
logger.debug("Validation worker %s started", worker_id)
async with self._validation_receive:
async for request in self._validation_receive:
if not self._running:
break
try:
# Process the validation request
result = await self._validate_message(request)
request.result_callback(result, None)
except Exception as e:
logger.exception("Error in validation worker %s", worker_id)
request.result_callback(ValidationResult.REJECT, e)
logger.debug("Validation worker %s stopped", worker_id)
async def _validate_message(self, request: ValidationRequest) -> ValidationResult:
"""Core validation logic with throttling"""
validators = request.validators
msg_forwarder = request.msg_forwarder
msg = request.msg
if not validators:
return ValidationResult.ACCEPT
# Separate sync and async validators
sync_validators = [v for v in validators if not v.is_async]
async_validators = [v for v in validators if v.is_async]
# Run synchronous validators first
for validator in sync_validators:
try:
# Apply per-topic throttling even for sync validators
if validator.throttle_semaphore:
validator.throttle_semaphore.acquire_nowait()
try:
result = validator.validator(msg_forwarder, msg)
if not result:
return ValidationResult.REJECT
finally:
validator.throttle_semaphore.release()
else:
result = validator.validator(msg_forwarder, msg)
if not result:
return ValidationResult.REJECT
except trio.WouldBlock:
# Per-topic throttling for sync validator
logger.debug("Sync validation throttled for topic %s", validator.topic)
return ValidationResult.THROTTLED
except Exception as e:
logger.exception(
"Sync validator failed for topic %s: %s", validator.topic, e
)
return ValidationResult.REJECT
# Handle async validators with global + per-topic throttling
if async_validators:
return await self._validate_async_validators(
async_validators, msg_forwarder, msg
)
return ValidationResult.ACCEPT
async def _validate_async_validators(
self, validators: list[TopicValidator], msg_forwarder: ID, msg: rpc_pb2.Message
) -> ValidationResult:
"""Handle async validators with proper throttling"""
if len(validators) == 1:
# Fast path for single validator
return await self._validate_single_async_validator(
validators[0], msg_forwarder, msg
)
# Multiple async validators - run them concurrently
try:
# Try to acquire global throttle slot
self._global_throttle.acquire_nowait()
except trio.WouldBlock:
logger.debug(
"Global validation throttle exceeded, dropping message from %s",
msg_forwarder,
)
return ValidationResult.THROTTLED
try:
async with trio.open_nursery() as nursery:
results = {}
async def run_validator(validator: TopicValidator, index: int) -> None:
"""Run a single async validator and store the result"""
nonlocal results
result = await self._validate_single_async_validator(
validator, msg_forwarder, msg
)
results[index] = result
# Start all validators concurrently
for i, validator in enumerate(validators):
nursery.start_soon(run_validator, validator, i)
# Process results - any reject or throttle causes overall failure
final_result = ValidationResult.ACCEPT
for result in results.values():
if result == ValidationResult.REJECT:
return ValidationResult.REJECT
elif result == ValidationResult.THROTTLED:
final_result = ValidationResult.THROTTLED
elif (
result == ValidationResult.IGNORE
and final_result == ValidationResult.ACCEPT
):
final_result = ValidationResult.IGNORE
return final_result
finally:
self._global_throttle.release()
return ValidationResult.IGNORE
async def _validate_single_async_validator(
self, validator: TopicValidator, msg_forwarder: ID, msg: rpc_pb2.Message
) -> ValidationResult:
"""Validate with a single async validator"""
# Apply per-topic throttling
if validator.throttle_semaphore:
try:
validator.throttle_semaphore.acquire_nowait()
except trio.WouldBlock:
logger.debug(
"Per-topic validation throttled for topic %s", validator.topic
)
return ValidationResult.THROTTLED
else:
# Fallback if no throttle semaphore configured
pass
try:
# Apply timeout if configured
result: bool
if validator.timeout:
with trio.fail_after(validator.timeout):
func = cast(AsyncValidatorFn, validator.validator)
result = await func(msg_forwarder, msg)
else:
func = cast(AsyncValidatorFn, validator.validator)
result = await func(msg_forwarder, msg)
return ValidationResult.ACCEPT if result else ValidationResult.REJECT
except trio.TooSlowError:
logger.debug("Validation timeout for topic %s", validator.topic)
return ValidationResult.IGNORE
except Exception as e:
logger.exception(
"Async validator failed for topic %s: %s", validator.topic, e
)
return ValidationResult.REJECT
finally:
if validator.throttle_semaphore:
validator.throttle_semaphore.release()
return ValidationResult.IGNORE