packer-cn/packer/provisioner.go

127 lines
3.5 KiB
Go

package packer
import (
"context"
"fmt"
"log"
"sync"
"time"
)
// A provisioner is responsible for installing and configuring software
// on a machine prior to building the actual image.
type Provisioner interface {
// Prepare is called with a set of configurations to setup the
// internal state of the provisioner. The multiple configurations
// should be merged in some sane way.
Prepare(...interface{}) error
// Provision is called to actually provision the machine. A context is
// given for cancellation, a UI is given to communicate with the user, and
// a communicator is given that is guaranteed to be connected to some
// machine so that provisioning can be done.
Provision(context.Context, Ui, Communicator, interface{}) error
}
// A HookedProvisioner represents a provisioner and information describing it
type HookedProvisioner struct {
Provisioner Provisioner
Config interface{}
TypeName string
}
// A Hook implementation that runs the given provisioners.
type ProvisionHook struct {
// The provisioners to run as part of the hook. These should already
// be prepared (by calling Prepare) at some earlier stage.
Provisioners []*HookedProvisioner
}
// Runs the provisioners in order.
func (h *ProvisionHook) Run(ctx context.Context, name string, ui Ui, comm Communicator, data interface{}) error {
// Shortcut
if len(h.Provisioners) == 0 {
return nil
}
if comm == nil {
return fmt.Errorf(
"No communicator found for provisioners! This is usually because the\n" +
"`communicator` config was set to \"none\". If you have any provisioners\n" +
"then a communicator is required. Please fix this to continue.")
}
for _, p := range h.Provisioners {
ts := CheckpointReporter.AddSpan(p.TypeName, "provisioner", p.Config)
err := p.Provisioner.Provision(ctx, ui, comm, data)
ts.End(err)
if err != nil {
return err
}
}
return nil
}
// PausedProvisioner is a Provisioner implementation that pauses before
// the provisioner is actually run.
type PausedProvisioner struct {
PauseBefore time.Duration
Provisioner Provisioner
}
func (p *PausedProvisioner) Prepare(raws ...interface{}) error {
return p.Provisioner.Prepare(raws...)
}
func (p *PausedProvisioner) Provision(ctx context.Context, ui Ui, comm Communicator, generatedData interface{}) error {
// Use a select to determine if we get cancelled during the wait
ui.Say(fmt.Sprintf("Pausing %s before the next provisioner...", p.PauseBefore))
select {
case <-time.After(p.PauseBefore):
case <-ctx.Done():
return ctx.Err()
}
return p.Provisioner.Provision(ctx, ui, comm, generatedData)
}
// DebuggedProvisioner is a Provisioner implementation that waits until a key
// press before the provisioner is actually run.
type DebuggedProvisioner struct {
Provisioner Provisioner
cancelCh chan struct{}
doneCh chan struct{}
lock sync.Mutex
}
func (p *DebuggedProvisioner) Prepare(raws ...interface{}) error {
return p.Provisioner.Prepare(raws...)
}
func (p *DebuggedProvisioner) Provision(ctx context.Context, ui Ui, comm Communicator, generatedData interface{}) error {
// Use a select to determine if we get cancelled during the wait
message := "Pausing before the next provisioner . Press enter to continue."
result := make(chan string, 1)
go func() {
line, err := ui.Ask(message)
if err != nil {
log.Printf("Error asking for input: %s", err)
}
result <- line
}()
select {
case <-result:
case <-ctx.Done():
return ctx.Err()
}
return p.Provisioner.Provision(ctx, ui, comm, generatedData)
}