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tps_limit_sliding_window_strategy.go
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tps_limit_sliding_window_strategy.go
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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
package impl
import (
"container/list"
"sync"
"time"
)
import (
"github.com/apache/dubbo-go/common/extension"
"github.com/apache/dubbo-go/filter/impl/tps"
)
func init() {
extension.SetTpsLimitStrategy("slidingWindow", NewSlidingWindowTpsLimitStrategyImpl)
}
/**
* it's thread-safe.
* "UserProvider":
* registry: "hangzhouzk"
* protocol : "dubbo"
* interface : "com.ikurento.user.UserProvider"
* ... # other configuration
* tps.limiter: "method-service" # the name of limiter
* tps.limit.strategy: "slidingWindow" # service-level
* methods:
* - name: "GetUser"
* tps.interval: 3000
* tps.limit.strategy: "slidingWindow" # method-level
*/
type SlidingWindowTpsLimitStrategyImpl struct {
rate int
interval int64
mutex *sync.Mutex
queue *list.List
}
func (impl *SlidingWindowTpsLimitStrategyImpl) IsAllowable() bool {
impl.mutex.Lock()
defer impl.mutex.Unlock()
// quick path
size := impl.queue.Len()
current := time.Now().UnixNano()
if size < impl.rate {
impl.queue.PushBack(current)
return true
}
// slow path
boundary := current - impl.interval
timestamp := impl.queue.Front()
// remove the element that out of the window
for timestamp != nil && timestamp.Value.(int64) < boundary {
impl.queue.Remove(timestamp)
timestamp = impl.queue.Front()
}
if impl.queue.Len() < impl.rate {
impl.queue.PushBack(current)
return true
}
return false
}
func NewSlidingWindowTpsLimitStrategyImpl(rate int, interval int) tps.TpsLimitStrategy {
return &SlidingWindowTpsLimitStrategyImpl{
rate: rate,
interval: int64(interval * 1000),
mutex: &sync.Mutex{},
queue: list.New(),
}
}