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|
package main
import (
"errors"
"net"
"os"
"strings"
jww "github.com/spf13/jwalterweatherman"
)
type interfaceContext struct {
PrimaryIP *net.IP
MacAddr *net.HardwareAddr
PrimaryHostname *string
}
func interfaceIsUsable(i *net.Interface) bool {
if i.Flags&net.FlagLoopback != 0 {
return false
}
if i.Flags&net.FlagUp == 0 {
return false
}
addrs, err := i.Addrs()
if err != nil || len(addrs) == 0 {
return false
}
if strings.HasPrefix(i.Name, "docker") {
return false
}
return true
}
func getPrimaryInterface() (*net.Interface, error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
}
if len(ifaces) == 0 {
return nil, errors.New("no interfaces found")
}
var iface net.Interface
for _, iface = range ifaces {
if !interfaceIsUsable(&iface) {
continue
} else {
break
}
}
if interfaceIsUsable(&iface) {
return &iface, nil
} else {
return nil, errors.New("no usable interfaces found")
}
}
func getInterfaceContext() (*interfaceContext, error) {
iface, err := getPrimaryInterface()
if err != nil {
return nil, err
}
// Validated to have at least this in interfaceIsUsable
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
primaryAddr := addrs[0].String()
primaryIP, _, err := net.ParseCIDR(primaryAddr)
if err != nil {
return nil, err
}
name, err := os.Hostname()
if err != nil {
jww.ERROR.Printf("Unable to resolve hostname, using localhost: %s", err.Error())
name = "localhost"
}
return &interfaceContext{
PrimaryIP: &primaryIP,
MacAddr: &iface.HardwareAddr,
PrimaryHostname: &name,
}, nil
}
|
