54 lines
1.4 KiB
Go
54 lines
1.4 KiB
Go
package internal
|
|
|
|
import (
|
|
"fmt"
|
|
"net"
|
|
)
|
|
|
|
// AddressManager allocates a new address (interface & port) a process
|
|
// can bind and keeps track of that.
|
|
type AddressManager struct {
|
|
port int
|
|
host string
|
|
}
|
|
|
|
// Initialize returns a address a process can listen on. It returns
|
|
// a tuple consisting of a free port and the hostname resolved to its IP.
|
|
func (d *AddressManager) Initialize() (port int, resolvedHost string, err error) {
|
|
if d.port != 0 {
|
|
return 0, "", fmt.Errorf("this AddressManager is already initialized")
|
|
}
|
|
addr, err := net.ResolveTCPAddr("tcp", "localhost:0")
|
|
if err != nil {
|
|
return
|
|
}
|
|
l, err := net.ListenTCP("tcp", addr)
|
|
if err != nil {
|
|
return
|
|
}
|
|
d.port = l.Addr().(*net.TCPAddr).Port
|
|
defer func() {
|
|
err = l.Close()
|
|
}()
|
|
d.host = addr.IP.String()
|
|
return d.port, d.host, nil
|
|
}
|
|
|
|
// Port returns the port that this AddressManager is managing. Port returns an
|
|
// error if this AddressManager has not yet been initialized.
|
|
func (d *AddressManager) Port() (int, error) {
|
|
if d.port == 0 {
|
|
return 0, fmt.Errorf("this AdressManager is not initialized yet")
|
|
}
|
|
return d.port, nil
|
|
}
|
|
|
|
// Host returns the host that this AddressManager is managing. Host returns an
|
|
// error if this AddressManager has not yet been initialized.
|
|
func (d *AddressManager) Host() (string, error) {
|
|
if d.host == "" {
|
|
return "", fmt.Errorf("this AdressManager is not initialized yet")
|
|
}
|
|
return d.host, nil
|
|
}
|