network.go

///// Main file

package inetwork

import (
    "errors"
    "net"
)

const InterfaceWlan = "wlan0"
const InterfaceEthernet = "eth0"

var netInterfaces = net.Interfaces

func GetIpAddress() (net.IP, error) {
    // List interfaces (mock this return ?)
    ifaces, err := netInterfaces()
    if err != nil {
        return nil, err
    }

    for _, i := range ifaces {
        // In my method, I'm interested only by eth0 and wlan0 (but in my dev env I don't have these interfaces)
        if i.Name == InterfaceWlan || i.Name == InterfaceEthernet {
            // Get IPs (mock method Addrs ?)
            addrs, err := i.Addrs()

            if err != nil || len(addrs) == 0 {
                continue
            }

            for _, addr := range addrs {
                // Check IP length
                if len(addr.String()) < 4{
                    continue
                }

                // Remove mask from IP
                ip := net.ParseIP(addr.String()[0:len(addr.String())-3])

                // Convert to IPv4
                if ip != nil && ip.To4() != nil {
                    return ip, nil
                }
            }
        }
    }

    return nil, errors.New("network: ip not found")
}