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// Copyright 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package utils
import (
"fmt"
"net"
"github.com/juju/loggo"
)
var logger = loggo.GetLogger("juju.utils")
// GetIPv4Address iterates through the addresses expecting the format from
// func (ifi *net.Interface) Addrs() ([]net.Addr, error)
func GetIPv4Address(addresses []net.Addr) (string, error) {
for _, addr := range addresses {
ip, _, err := net.ParseCIDR(addr.String())
if err != nil {
return "", err
}
ipv4 := ip.To4()
if ipv4 == nil {
continue
}
return ipv4.String(), nil
}
return "", fmt.Errorf("no addresses match")
}
// GetAddressForInterface looks for the network interface
// and returns the IPv4 address from the possible addresses.
func GetAddressForInterface(interfaceName string) (string, error) {
iface, err := net.InterfaceByName(interfaceName)
if err != nil {
logger.Errorf("cannot find network interface %q: %v", interfaceName, err)
return "", err
}
addrs, err := iface.Addrs()
if err != nil {
logger.Errorf("cannot get addresses for network interface %q: %v", interfaceName, err)
return "", err
}
return GetIPv4Address(addrs)
}
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