Packet Loss

Packet loss is measured over UDP, so it does not go through a proxy. A server that does not serve the packet loss protocol returns ErrUnsupported. How a Test Works explains the counts and how the loss is calculated.

Approach	Use it to
`Client.PacketLoss`	Measure the loss to one server for a while
The packet loss analyzer	Receive each sample as it arrives, or combine several servers

One measurement

PacketLoss measures until its context ends, so give it a timeout. A failed measurement still returns the counts it saw:

lossCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
packetLoss, err := client.PacketLoss(lossCtx, server)
cancel()

if err != nil {
	log.Println(err)
}

fmt.Println(packetLoss, packetLoss.LossPercent())

LossPercent returns -1 when the server received nothing.

The packet loss analyzer

client.NewPacketLossAnalyzer(options) creates an analyzer that connects the way the client does. Pass nil for the default options.

Method	Does
`Run(host, callback)`	Measures one server, and calls `callback` with each sample
`RunMulti(hosts)`	Measures several servers at once, and returns their combined counts
`RunWithContext`, `RunMultiWithContext`	The same, ending when a context ends

This program uses both. The packet loss example runs the analyzer on every available server at once.

package main

import (
	"context"
	"fmt"
	"github.com/nicholas-fedor/speedtest-go/v2/speedtest"
	"log"
)

func checkError(err error) {
	if err != nil {
		log.Fatal(err)
	}
}

// Note: The current packet loss analyzer does not support udp over http.
// This means we cannot get packet loss through a proxy.
func main() {
	// Retrieve the server with the lowest latency
	speedtestClient, err := speedtest.New()
	checkError(err)
	serverList, err := speedtestClient.FetchServers(context.Background())
	checkError(err)
	targets, err := serverList.FindServer([]int{})
	checkError(err)

	// Create a packet loss analyzer that connects the way the client does, with default options
	analyzer := speedtestClient.NewPacketLossAnalyzer(nil)

	// Perform packet loss analysis on the target server
	for _, server := range targets {
		err := analyzer.Run(server.Host, func(packetLoss *speedtest.PacketLossStats) {
			fmt.Println(packetLoss, server.Host, server.Name)
			// fmt.Println(packetLoss.Loss())
		})
		checkError(err)
	}

	// or test several servers at the same time.
	packetLoss, err := analyzer.RunMulti(serverList.Available().Hosts())
	checkError(err)
	fmt.Println(packetLoss)
}

Measurements Migrating to v2