minio/pkg/api/quota/rate_limiter.go

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/*
* Minimalist Object Storage, (C) 2015 Minio, Inc.
*
* 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.
*/
package quota
import "net/http"
// rateLimit
type rateLimit struct {
handler http.Handler
rateQueue chan bool
}
func (c *rateLimit) Add() {
c.rateQueue <- true // fill in the queue
return
}
func (c *rateLimit) Remove() {
<-c.rateQueue // invalidate the queue, after the request is served
return
}
// ServeHTTP is an http.Handler ServeHTTP method
func (c *rateLimit) ServeHTTP(w http.ResponseWriter, req *http.Request) {
c.Add() // add
c.handler.ServeHTTP(w, req) // serve
c.Remove() // remove
}
// RateLimit limits the number of concurrent http requests
func RateLimit(handle http.Handler, limit int) http.Handler {
return &rateLimit{
handler: handle,
rateQueue: make(chan bool, limit),
}
}