107 lines
2.3 KiB
Go
107 lines
2.3 KiB
Go
package limiter
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import (
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"io"
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"net/http"
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"github.com/juju/ratelimit"
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)
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type staticLimiter struct {
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upstream *ratelimit.Bucket
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downstream *ratelimit.Bucket
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}
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// NewStaticLimiter constructs a Limiter with a fixed (static) upload and
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// download rate cap
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func NewStaticLimiter(uploadKb, downloadKb int) Limiter {
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var (
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upstreamBucket *ratelimit.Bucket
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downstreamBucket *ratelimit.Bucket
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)
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if uploadKb > 0 {
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upstreamBucket = ratelimit.NewBucketWithRate(toByteRate(uploadKb), int64(toByteRate(uploadKb)))
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}
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if downloadKb > 0 {
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downstreamBucket = ratelimit.NewBucketWithRate(toByteRate(downloadKb), int64(toByteRate(downloadKb)))
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}
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return staticLimiter{
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upstream: upstreamBucket,
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downstream: downstreamBucket,
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}
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}
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func (l staticLimiter) Upstream(r io.Reader) io.Reader {
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return l.limitReader(r, l.upstream)
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}
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func (l staticLimiter) UpstreamWriter(w io.Writer) io.Writer {
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return l.limitWriter(w, l.upstream)
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}
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func (l staticLimiter) Downstream(r io.Reader) io.Reader {
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return l.limitReader(r, l.downstream)
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}
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func (l staticLimiter) DownstreamWriter(w io.Writer) io.Writer {
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return l.limitWriter(w, l.downstream)
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}
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type roundTripper func(*http.Request) (*http.Response, error)
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func (rt roundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
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return rt(req)
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}
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func (l staticLimiter) roundTripper(rt http.RoundTripper, req *http.Request) (*http.Response, error) {
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type readCloser struct {
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io.Reader
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io.Closer
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}
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if req.Body != nil {
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req.Body = &readCloser{
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Reader: l.Upstream(req.Body),
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Closer: req.Body,
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}
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}
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res, err := rt.RoundTrip(req)
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if res != nil && res.Body != nil {
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res.Body = &readCloser{
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Reader: l.Downstream(res.Body),
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Closer: res.Body,
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}
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}
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return res, err
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}
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// Transport returns an HTTP transport limited with the limiter l.
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func (l staticLimiter) Transport(rt http.RoundTripper) http.RoundTripper {
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return roundTripper(func(req *http.Request) (*http.Response, error) {
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return l.roundTripper(rt, req)
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})
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}
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func (l staticLimiter) limitReader(r io.Reader, b *ratelimit.Bucket) io.Reader {
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if b == nil {
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return r
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}
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return ratelimit.Reader(r, b)
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}
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func (l staticLimiter) limitWriter(w io.Writer, b *ratelimit.Bucket) io.Writer {
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if b == nil {
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return w
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}
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return ratelimit.Writer(w, b)
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}
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func toByteRate(val int) float64 {
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return float64(val) * 1024.
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}
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