This package provides basic traffic shaping for Go's stream-oriented network connections. It gives the ability to define global and per-connection (local) bandwidth limits.
limiter := tcplimit.NewLimiter()
// Set 1MB/s limit for cumulative traffic...
limiter.SetGlobalLimit(rate.Limit(1024 * 1024))
// ...but 50kB/s limit per one connection
limiter.SetLocalLimit(rate.Limit(10 * 1024))
// ...
limitedConn := limiter.LimitConn(conn)
go handleConnection(limitedConn)
// ...
// When we finally decided that we didn't want to cap global bandwidth
// and give each active client a larger piece of traffic.
limiter.SetGlobalLimit(rate.Inf)
limiter.SetLocalLimit(rate.Limit(100 * 1024)) // 100kB/sAlthough standard unit tests execute fast, it is advised to run also the "slow tests" (using slow build tag), which verify shaping constraints:
go test -v -race -tags slow .
As a bonus, this package provides a tcplmit-proxy tool that is a basic HTTP proxy that can be used for traffic shaping.
Proxy can be installed and started by invoking:
go install github.com/ksinica/tcplimit/cmd/tcplimit-proxy@latest
tcplimit-proxy --port 8080
Then it can be used for example with wget utility:
wget https://releases.ubuntu.com/22.04.3/ubuntu-22.04.3-desktop-amd64.iso -e use_proxy=yes -e https_proxy=127.0.0.1:8080
To change the global limit, one can do an HTTP PUT request on the /limits/global endpoint with a desired value as a payload:
curl -X PUT --data "524288" http://localhost:8080/limits/global
The local limit can be manipulated in a similar way:
curl -X PUT --data "51200" http://localhost:8080/limits/local
Source code is available under the MIT License.