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# Copyright (c) 2022 NVIDIA
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import time
from collections import defaultdict
from swift.common.request_helpers import split_and_validate_path
from swift.common.swob import Request, HTTPTooManyBackendRequests
from swift.common.utils import get_logger, non_negative_float, \
EventletRateLimiter
RATE_LIMITED_METHODS = ('GET', 'HEAD', 'PUT', 'POST', 'DELETE', 'UPDATE',
'REPLICATE')
class BackendRateLimitMiddleware(object):
"""
Backend rate-limiting middleware.
Rate-limits requests to backend storage node devices. Each device is
independently rate-limited. All requests with a 'GET', 'HEAD', 'PUT',
'POST', 'DELETE', 'UPDATE' or 'REPLICATE' method are included in a device's
rate limit.
If a request would cause the rate-limit to be exceeded then a response with
a 529 status code is returned.
"""
def __init__(self, app, conf, logger=None):
self.app = app
self.logger = logger or get_logger(conf, log_route='backend_ratelimit')
self.requests_per_device_per_second = non_negative_float(
conf.get('requests_per_device_per_second', 0.0))
self.requests_per_device_rate_buffer = non_negative_float(
conf.get('requests_per_device_rate_buffer', 1.0))
# map device -> RateLimiter
self.rate_limiters = defaultdict(
lambda: EventletRateLimiter(
max_rate=self.requests_per_device_per_second,
rate_buffer=self.requests_per_device_rate_buffer,
running_time=time.time(),
burst_after_idle=True))
def __call__(self, env, start_response):
"""
WSGI entry point.
:param env: WSGI environment dictionary
:param start_response: WSGI callable
"""
req = Request(env)
handler = self.app
if req.method in RATE_LIMITED_METHODS:
try:
device, partition, _ = split_and_validate_path(req, 1, 3, True)
int(partition) # check it's a valid partition
rate_limiter = self.rate_limiters[device]
if not rate_limiter.is_allowed():
self.logger.increment('backend.ratelimit')
handler = HTTPTooManyBackendRequests()
except Exception: # noqa
# request may not have device/partition e.g. a healthcheck req
pass
return handler(env, start_response)
def filter_factory(global_conf, **local_conf):
conf = global_conf.copy()
conf.update(local_conf)
def backend_ratelimit_filter(app):
return BackendRateLimitMiddleware(app, conf)
return backend_ratelimit_filter
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