How do I get the local IP address in Go?

To ensure that you get a non-loopback address, simply check that an IP is not a loopback when you are iterating.

// GetLocalIP returns the non loopback local IP of the host
func GetLocalIP() string {
    addrs, err := net.InterfaceAddrs()
    if err != nil {
        return ""
    }
    for _, address := range addrs {
        // check the address type and if it is not a loopback the display it
        if ipnet, ok := address.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
            if ipnet.IP.To4() != nil {
                return ipnet.IP.String()
            }
        }
    }
    return ""
}

Here is a better solution to retrieve the preferred outbound ip address when there are multiple ip interfaces exist on the machine.

import (
    "log"
    "net"
    "strings"
)

// Get preferred outbound ip of this machine
func GetOutboundIP() net.IP {
    conn, err := net.Dial("udp", "8.8.8.8:80")
    if err != nil {
        log.Fatal(err)
    }
    defer conn.Close()

    localAddr := conn.LocalAddr().(*net.UDPAddr)

    return localAddr.IP
}

You need to loop through all network interfaces

ifaces, err := net.Interfaces()
// handle err
for _, i := range ifaces {
    addrs, err := i.Addrs()
    // handle err
    for _, addr := range addrs {
        var ip net.IP
        switch v := addr.(type) {
        case *net.IPNet:
                ip = v.IP
        case *net.IPAddr:
                ip = v.IP
        }
        // process IP address
    }
}

Play (taken from util/helper.go)