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goproxy/utils/io-limiter.go

98 lines
2.0 KiB
Go

package utils
import (
"context"
"io"
"time"
"golang.org/x/time/rate"
)
const burstLimit = 1000 * 1000 * 1000
type Reader struct {
r io.Reader
limiter *rate.Limiter
ctx context.Context
}
type Writer struct {
w io.Writer
limiter *rate.Limiter
ctx context.Context
}
// NewReader returns a reader that implements io.Reader with rate limiting.
func NewReader(r io.Reader) *Reader {
return &Reader{
r: r,
ctx: context.Background(),
}
}
// NewReaderWithContext returns a reader that implements io.Reader with rate limiting.
func NewReaderWithContext(r io.Reader, ctx context.Context) *Reader {
return &Reader{
r: r,
ctx: ctx,
}
}
// NewWriter returns a writer that implements io.Writer with rate limiting.
func NewWriter(w io.Writer) *Writer {
return &Writer{
w: w,
ctx: context.Background(),
}
}
// NewWriterWithContext returns a writer that implements io.Writer with rate limiting.
func NewWriterWithContext(w io.Writer, ctx context.Context) *Writer {
return &Writer{
w: w,
ctx: ctx,
}
}
// SetRateLimit sets rate limit (bytes/sec) to the reader.
func (s *Reader) SetRateLimit(bytesPerSec float64) {
s.limiter = rate.NewLimiter(rate.Limit(bytesPerSec), burstLimit)
s.limiter.AllowN(time.Now(), burstLimit) // spend initial burst
}
// Read reads bytes into p.
func (s *Reader) Read(p []byte) (int, error) {
if s.limiter == nil {
return s.r.Read(p)
}
n, err := s.r.Read(p)
if err != nil {
return n, err
}
if err := s.limiter.WaitN(s.ctx, n); err != nil {
return n, err
}
return n, nil
}
// SetRateLimit sets rate limit (bytes/sec) to the writer.
func (s *Writer) SetRateLimit(bytesPerSec float64) {
s.limiter = rate.NewLimiter(rate.Limit(bytesPerSec), burstLimit)
s.limiter.AllowN(time.Now(), burstLimit) // spend initial burst
}
// Write writes bytes from p.
func (s *Writer) Write(p []byte) (int, error) {
if s.limiter == nil {
return s.w.Write(p)
}
n, err := s.w.Write(p)
if err != nil {
return n, err
}
if err := s.limiter.WaitN(s.ctx, n); err != nil {
return n, err
}
return n, err
}