packer-cn/builder/linode/step_create_ssh_key.go

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package linode
import (
"context"
"crypto/rand"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"fmt"
"io/ioutil"
"os"
"github.com/hashicorp/packer/helper/multistep"
"github.com/hashicorp/packer/packer"
"golang.org/x/crypto/ssh"
)
// StepCreateSSHKey represents a Packer build step that generates SSH key pairs.
type StepCreateSSHKey struct {
Debug bool
DebugKeyPath string
}
// Run executes the Packer build step that generates SSH key pairs.
// The key pairs are added to the ssh config
func (s *StepCreateSSHKey) Run(_ context.Context, state multistep.StateBag) multistep.StepAction {
ui := state.Get("ui").(packer.Ui)
config := state.Get("config").(*Config)
if config.Comm.SSHPrivateKeyFile != "" {
ui.Say("Using existing SSH private key")
privateKeyBytes, err := ioutil.ReadFile(config.Comm.SSHPrivateKeyFile)
if err != nil {
state.Put("error", fmt.Errorf(
"Error loading configured private key file: %s", err))
return multistep.ActionHalt
}
config.Comm.SSHPrivateKey = privateKeyBytes
config.Comm.SSHPublicKey = nil
return multistep.ActionContinue
}
ui.Say("Creating temporary SSH key for instance...")
priv, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
err := fmt.Errorf("Error creating temporary ssh key: %s", err)
state.Put("error", err)
ui.Error(err.Error())
return multistep.ActionHalt
}
priv_blk := pem.Block{
Type: "RSA PRIVATE KEY",
Headers: nil,
Bytes: x509.MarshalPKCS1PrivateKey(priv),
}
pub, err := ssh.NewPublicKey(&priv.PublicKey)
if err != nil {
err := fmt.Errorf("Error creating temporary ssh key: %s", err)
state.Put("error", err)
ui.Error(err.Error())
return multistep.ActionHalt
}
config.Comm.SSHPrivateKey = pem.EncodeToMemory(&priv_blk)
config.Comm.SSHPublicKey = ssh.MarshalAuthorizedKey(pub)
// Linode has a serious issue with the newline that the ssh package appends to the end of the key.
if config.Comm.SSHPublicKey[len(config.Comm.SSHPublicKey)-1] == '\n' {
config.Comm.SSHPublicKey = config.Comm.SSHPublicKey[:len(config.Comm.SSHPublicKey)-1]
}
if s.Debug {
ui.Message(fmt.Sprintf("Saving key for debug purposes: %s", s.DebugKeyPath))
f, err := os.Create(s.DebugKeyPath)
if err != nil {
state.Put("error", fmt.Errorf("Error saving debug key: %s", err))
return multistep.ActionHalt
}
// Write out the key
err = pem.Encode(f, &priv_blk)
f.Close()
if err != nil {
state.Put("error", fmt.Errorf("Error saving debug key: %s", err))
return multistep.ActionHalt
}
}
return multistep.ActionContinue
}
// Nothing to clean up. SSH keys are associated with a single Linode instance.
func (s *StepCreateSSHKey) Cleanup(state multistep.StateBag) {}