packer-cn/builder/amazon/chroot/step_flock.go

73 lines
1.5 KiB
Go

package chroot
import (
"fmt"
"github.com/hashicorp/packer/packer"
"github.com/mitchellh/multistep"
"log"
"os"
"path/filepath"
)
// StepFlock provisions the instance within a chroot.
//
// Produces:
// flock_cleanup Cleanup - To perform early cleanup
type StepFlock struct {
fh *os.File
}
func (s *StepFlock) Run(state multistep.StateBag) multistep.StepAction {
ui := state.Get("ui").(packer.Ui)
lockfile := "/var/lock/packer-chroot/lock"
if err := os.MkdirAll(filepath.Dir(lockfile), 0755); err != nil {
err := fmt.Errorf("Error creating lock: %s", err)
state.Put("error", err)
ui.Error(err.Error())
return multistep.ActionHalt
}
log.Printf("Obtaining lock: %s", lockfile)
f, err := os.Create(lockfile)
if err != nil {
err := fmt.Errorf("Error creating lock: %s", err)
state.Put("error", err)
ui.Error(err.Error())
return multistep.ActionHalt
}
// LOCK!
if err := lockFile(f); err != nil {
err := fmt.Errorf("Error obtaining lock: %s", err)
state.Put("error", err)
ui.Error(err.Error())
return multistep.ActionHalt
}
// Set the file handle, we can't close it because we need to hold
// the lock.
s.fh = f
state.Put("flock_cleanup", s)
return multistep.ActionContinue
}
func (s *StepFlock) Cleanup(state multistep.StateBag) {
s.CleanupFunc(state)
}
func (s *StepFlock) CleanupFunc(state multistep.StateBag) error {
if s.fh == nil {
return nil
}
log.Printf("Unlocking: %s", s.fh.Name())
if err := unlockFile(s.fh); err != nil {
return err
}
s.fh = nil
return nil
}