tcpshaper

Golang Middleware for rate limiting tcp traffic

Overview

This package provides middleware and utility functions for rate limiting net.Listener connections.

It makes use of the https://godoc.org/golang.org/x/time/rate package to provide the rate limiting itself.

Usage

Listener

package main

import (
  "context"
  "fmt"
  "github.com/gerritjvv/tcpshaper/bandwidth"
  "net"
)

func main() { 
  // Get a Listener, e.g tcp on any port
  tcpListner, err := net.Listen("tcp", ":0")
  if err != nil {
   panic(err)
  }

  ctx := context.Background()

  // Configure rate limit to:
  // total read+write traffic == 1mbs
  // Each connection read+write == 2kbs
  // The maximum that can be read or written at any one time is 2kb
  serverRate := bandwidth.NewRateConfig(1024*1024, 2048)
  connRate := bandwidth.NewRateConfig(2048, 2048)

  listener := bandwidth.NewListener(ctx, &bandwidth.ListenerConfig{
    ReadServerRate:  serverRate,
    WriteServerRate: serverRate,
    ReadConnRate:    connRate,
    WriteConnRate:   connRate,
  }, tcpListner)

  // Now use the listener
  // e.g listener.Accept()
  
  err = listener.Close()
  if err != nil {
    fmt.Printf("error while closing listener %s", err)
  }
}

Connection wrapping

package main
import (
  "context"
  "github.com/gerritjvv/tcpshaper/bandwidth"
)

func main()  {
 
  // Setup a limiter with a 2kb/s limit, and max 2kb per read event.
  readLimiter := bandwidth.NewBandwidthLimiter(bandwidth.NewRateConfig(2048, 2048))

  // Setup a "noop" limiter with infinite rates
  writeLimiter := bandwidth.NewBandwidthLimiter(bandwidth.NewRateConfig(bandwidth.Inf, 0))

  ctx := context.Background()

  conn := getConn() // get a connection

  rConn := bandwidth.NewRateLimitedConn(ctx, readLimiter, writeLimiter, conn)

  // Write is not rate limited
  _, _ = rConn.Write([]byte("test string"))

  // Read is reate limited
  _, _ = rConn.Read(make([]byte, 1))

  _ = rConn.Close()

}

Build and Test

## to build the library
./build.sh build

## run tests
./build.sh test

## show test coverage reports
./build.sh report