124 lines
2.8 KiB
Go
124 lines
2.8 KiB
Go
package net
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"log"
|
|
"math/rand"
|
|
"net"
|
|
"strconv"
|
|
"time"
|
|
|
|
"github.com/hashicorp/packer/common/filelock"
|
|
"github.com/hashicorp/packer/common/retry"
|
|
"github.com/hashicorp/packer/packer"
|
|
)
|
|
|
|
var _ net.Listener = &Listener{}
|
|
|
|
// Listener wraps a net.Lister with some magic packer capabilies. For example
|
|
// until you call Listener.Close, any call to ListenRangeConfig.Listen cannot
|
|
// bind to Port. Packer tries tells moving parts which port they can use, but
|
|
// often the port has to be released before a 3rd party is started, like a VNC
|
|
// server.
|
|
type Listener struct {
|
|
// Listener can be closed but Port will be file locked by packer until
|
|
// Close is called.
|
|
net.Listener
|
|
Port int
|
|
Address string
|
|
lock *filelock.Flock
|
|
}
|
|
|
|
func (l *Listener) Close() error {
|
|
err := l.lock.Unlock()
|
|
if err != nil {
|
|
log.Printf("cannot unlock lockfile %#v: %v", l, err)
|
|
}
|
|
return l.Listener.Close()
|
|
}
|
|
|
|
// ListenRangeConfig contains options for listening to a free address [Min,Max)
|
|
// range. ListenRangeConfig wraps a net.ListenConfig.
|
|
type ListenRangeConfig struct {
|
|
// like "tcp" or "udp". defaults to "tcp".
|
|
Network string
|
|
Addr string
|
|
Min, Max int
|
|
net.ListenConfig
|
|
}
|
|
|
|
// Listen tries to Listen to a random open TCP port in the [min, max) range
|
|
// until ctx is cancelled.
|
|
// Listen uses net.ListenConfig.Listen internally.
|
|
func (lc ListenRangeConfig) Listen(ctx context.Context) (*Listener, error) {
|
|
if lc.Network == "" {
|
|
lc.Network = "tcp"
|
|
}
|
|
portRange := lc.Max - lc.Min
|
|
|
|
var listener *Listener
|
|
|
|
err := retry.Config{
|
|
RetryDelay: func() time.Duration { return 1 * time.Millisecond },
|
|
}.Run(ctx, func(context.Context) error {
|
|
port := lc.Min
|
|
if portRange > 0 {
|
|
port += rand.Intn(portRange)
|
|
}
|
|
|
|
lockFilePath, err := packer.CachePath("port", strconv.Itoa(port))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
lock := filelock.New(lockFilePath)
|
|
locked, err := lock.TryLock()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if !locked {
|
|
return ErrPortFileLocked(port)
|
|
}
|
|
|
|
l, err := lc.ListenConfig.Listen(ctx, lc.Network, fmt.Sprintf("%s:%d", lc.Addr, port))
|
|
if err != nil {
|
|
if err := lock.Unlock(); err != nil {
|
|
log.Fatalf("Could not unlock file lock for port %d: %v", port, err)
|
|
}
|
|
return &ErrPortBusy{
|
|
Port: port,
|
|
Err: err,
|
|
}
|
|
}
|
|
|
|
log.Printf("Found available port: %d on IP: %s", port, lc.Addr)
|
|
listener = &Listener{
|
|
Address: lc.Addr,
|
|
Port: port,
|
|
Listener: l,
|
|
lock: lock,
|
|
}
|
|
return nil
|
|
})
|
|
return listener, err
|
|
}
|
|
|
|
type ErrPortFileLocked int
|
|
|
|
func (port ErrPortFileLocked) Error() string {
|
|
return fmt.Sprintf("Port %d is file locked", port)
|
|
}
|
|
|
|
type ErrPortBusy struct {
|
|
Port int
|
|
Err error
|
|
}
|
|
|
|
func (err *ErrPortBusy) Error() string {
|
|
if err == nil {
|
|
return "<nil>"
|
|
}
|
|
return fmt.Sprintf("port %d cannot be opened: %v", err.Port, err.Err)
|
|
}
|