There are two components of getting detailed info about an IP.

• A GeoIP database
• A library to look up the DB

These DBs are not free and have a proprietary format. So a library is required to perform lookups.
One such format is MaxMind and used by GeoIP2 & GeoLite2 DBs.

More @ https://github.com/oschwald/maxminddb-golang

A test program to get detailed IP information

$ cat mytest.go                                                                                                                                          [18:46:01]
//package maxminddb_test
package main

import (
        "fmt"
        "log"
        "net"

        "github.com/oschwald/maxminddb-golang"
)

// This example shows how to decode to a struct
func ExampleReader_Lookup_struct() {
        db, err := maxminddb.Open("./tests/static/GeoIP2-City.mmdb")
        if err != nil {
                log.Fatal(err)
        }
        defer db.Close()

        ip := net.ParseIP("81.2.69.142")

        var record interface{}
        err = db.Lookup(ip, &record)
        if err != nil {
                log.Fatal(err)
        }
        fmt.Print(record)
}

func main() {
        ExampleReader_Lookup_struct()
}

Note that the lookup assumes an interface type. The reason is that the API allows the application to specify what fields to lookup.

You can decide on the record structure after dumping the complete info and picking what you need.

References

• https://geoip2.readthedocs.io/en/latest/
• https://dev.maxmind.com/geoip/geoip2/downloadable/#MaxMind_APIs

Written with StackEdit.