country-latency-metronomy

country-latency-metronomy

A golang package for measuring latency to an IP address with a fallback, "best effort" mechanism.

The package is thread safe and includes caching of whois queries so is ideal for running in goroutines for measuring latency to many IP addresses in parallel.

How it works

The function GetLatency will:

1. Use ICMP echo to measure latency to the destination IP
2. If previous step fails:
   1. Get country code of the destination IP using RIPE database (whois)
   2. Run a traceroute to the destination IP, record all hops
   3. Take latest successful traceroute hop that matches the country code of the destination IP, use this as a substitute destination IP
   4. Use ICMP echo to measure latency to substitute destination IP

It will measure:

• Mean Latency
• Median Latency
• P90 Latency
• Packet Loss

CLI tool example

A small example CLI tool is included, main.go, to show how the package works:

$ sudo go run main.go -ip-address 82.88.43.13 -debug
DEBU[0000] Ping test successful to '82.88.43.13': 190 avg
DEBU[0000] Starting latancy analysis of '82.88.43.13'

Successful: true
Destination: 82.88.43.13
Country code: it
Alternate destination:
Median latency: 185.0ms

And when the fallback mechanism is used:

$ sudo go run main.go -ip-address 138.120.154.124 -debug
DEBU[0002] Ping failed to '138.120.154.124', no reply
DEBU[0002] Starting traceroute to '138.120.154.124'
DEBU[0026] Traceroute to '138.120.154.124' finished, 16 hops
DEBU[0026] Filtering traceroute results for country code 'us'
DEBU[0026] Found latest good hop '171.102.250.18'
DEBU[0026] Starting latancy analysis of '171.102.250.18'

Successful: true
Destination: 138.120.154.124
Country code: us
Alternate destination: 171.102.250.18
Median latency: 200.0ms

It is required to run the CLI tool with root permission as it creates raw sockets

Package example

package main

import (
	"fmt"

	"github.com/max-rocket-internet/country-latency-metronomy/pkg/latency"
	log "github.com/sirupsen/logrus"
)

func main() {
	log.SetLevel(log.DebugLevel)

	destination := latency.Destination{Ip: "124.120.154.1"}
	result, _ := latency.GetLatency(destination)

	fmt.Printf("%+v\n", result)
}

Output:

DEBU[0002] Ping failed to '124.120.154.1', no reply
DEBU[0002] Starting traceroute to '124.120.154.1'
DEBU[0026] Traceroute to '124.120.154.1' finished, 16 hops
DEBU[0026] Filtering traceroute results for country code 'th'
DEBU[0026] Found latest good hop '171.102.249.169'
DEBU[0026] Starting latancy analysis of '171.102.249.169'

{Ip:124.120.154.1 CountryCode:th AlternativeIP:171.102.249.169 ErrorMessage: Successful:true Latency:{LatencyMeanMs:214.9 LatencyMedianMs:201 LatencyP90Ms:222 PacketLoss:0}}