Creates a final "cleanup" provisioner to run if an error occurs during a provisioning step, allowing users to perform any custom cleanup tasks that must happen on the VM before the VM is shut down and destroyed.

common/step_provision.go

@@ -2,6 +2,7 @@ package common
 
 import (
 	"context"
+	"fmt"
 	"log"
 	"time"
 
@@ -22,7 +23,8 @@ type StepProvision struct {
 	Comm packer.Communicator
 }
 
-func (s *StepProvision) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
+func (s *StepProvision) runWithHook(ctx context.Context, state multistep.StateBag, hooktype string) multistep.StepAction {
+	// hooktype will be either packer.HookProvision or packer.HookCleanupProvision
 	comm := s.Comm
 	if comm == nil {
 		raw, ok := state.Get("communicator").(packer.Communicator)
@@ -35,17 +37,29 @@ func (s *StepProvision) Run(ctx context.Context, state multistep.StateBag) multi
 
 	// Run the provisioner in a goroutine so we can continually check
 	// for cancellations...
-	log.Println("Running the provision hook")
+	if hooktype == packer.HookProvision {
+		log.Println("Running the provision hook")
+	} else if hooktype == packer.HookCleanupProvision {
+		ui.Say("Provisioning step had errors: Running the cleanup provisioner, if present...")
+	}
 	errCh := make(chan error, 1)
 	go func() {
-		errCh <- hook.Run(ctx, packer.HookProvision, ui, comm, nil)
+		errCh <- hook.Run(ctx, hooktype, ui, comm, nil)
 	}()
 
 	for {
 		select {
 		case err := <-errCh:
 			if err != nil {
-				state.Put("error", err)
+				if hooktype == packer.HookProvision {
+					// We don't overwrite the error if it's a cleanup
+					// provisioner being run.
+					state.Put("error", err)
+				} else if hooktype == packer.HookCleanupProvision {
+					origErr := state.Get("error").(error)
+					state.Put("error", fmt.Errorf("Cleanup failed: %s. "+
+						"Original Provisioning error: %s", err, origErr))
+				}
 				return multistep.ActionHalt
 			}
 
@@ -62,4 +76,15 @@ func (s *StepProvision) Run(ctx context.Context, state multistep.StateBag) multi
 	}
 }
 
-func (*StepProvision) Cleanup(multistep.StateBag) {}
+func (s *StepProvision) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
+	return s.runWithHook(ctx, state, packer.HookProvision)
+}
+
+func (s *StepProvision) Cleanup(state multistep.StateBag) {
+	// We have a "final" provisioner that gets defined by "on-error-script"
+	// which we only call if there's an error during the provision run and
+	// the "on-error-script" is defined.
+	if _, ok := state.GetOk("error"); ok {
+		s.runWithHook(context.Background(), state, packer.HookCleanupProvision)
+	}
+}

packer/build.go

@@ -84,15 +84,16 @@ type Build interface {
 // multiple files, of course, but it should be for only a single provider
 // (such as VirtualBox, EC2, etc.).
 type coreBuild struct {
-	name           string
-	builder        Builder
-	builderConfig  interface{}
-	builderType    string
-	hooks          map[string][]Hook
-	postProcessors [][]coreBuildPostProcessor
-	provisioners   []coreBuildProvisioner
-	templatePath   string
-	variables      map[string]string
+	name               string
+	builder            Builder
+	builderConfig      interface{}
+	builderType        string
+	hooks              map[string][]Hook
+	postProcessors     [][]coreBuildPostProcessor
+	provisioners       []coreBuildProvisioner
+	cleanupProvisioner coreBuildProvisioner
+	templatePath       string
+	variables          map[string]string
 
 	debug         bool
 	force         bool
@@ -164,6 +165,17 @@ func (b *coreBuild) Prepare() (warn []string, err error) {
 		}
 	}
 
+	// Prepare the on-error-cleanup provisioner
+	if b.cleanupProvisioner.pType != "" {
+		configs := make([]interface{}, len(b.cleanupProvisioner.config), len(b.cleanupProvisioner.config)+1)
+		copy(configs, b.cleanupProvisioner.config)
+		configs = append(configs, packerConfig)
+		err = b.cleanupProvisioner.provisioner.Prepare(configs...)
+		if err != nil {
+			return
+		}
+	}
+
 	// Prepare the post-processors
 	for _, ppSeq := range b.postProcessors {
 		for _, corePP := range ppSeq {
@@ -222,6 +234,17 @@ func (b *coreBuild) Run(ctx context.Context, originalUi Ui) ([]Artifact, error)
 		})
 	}
 
+	if b.cleanupProvisioner.pType != "" {
+		hookedCleanupProvisioner := &HookedProvisioner{
+			b.cleanupProvisioner.provisioner,
+			b.cleanupProvisioner.config,
+			b.cleanupProvisioner.pType,
+		}
+		hooks[HookCleanupProvision] = []Hook{&ProvisionHook{
+			Provisioners: []*HookedProvisioner{hookedCleanupProvisioner},
+		}}
+	}
+
 	hook := &DispatchHook{Mapping: hooks}
 	artifacts := make([]Artifact, 0, 1)
 

packer/core.go

@@ -112,6 +112,49 @@ func (c *Core) BuildNames() []string {
 	return r
 }
 
+func (c *Core) generateCoreBuildProvisioner(rawP *template.Provisioner, rawName string) (coreBuildProvisioner, error) {
+	// Get the provisioner
+	cbp := coreBuildProvisioner{}
+	provisioner, err := c.components.Provisioner(rawP.Type)
+	if err != nil {
+		return cbp, fmt.Errorf(
+			"error initializing provisioner '%s': %s",
+			rawP.Type, err)
+	}
+	if provisioner == nil {
+		return cbp, fmt.Errorf(
+			"provisioner type not found: %s", rawP.Type)
+	}
+
+	// Get the configuration
+	config := make([]interface{}, 1, 2)
+	config[0] = rawP.Config
+	if rawP.Override != nil {
+		if override, ok := rawP.Override[rawName]; ok {
+			config = append(config, override)
+		}
+	}
+	// If we're pausing, we wrap the provisioner in a special pauser.
+	if rawP.PauseBefore > 0 {
+		provisioner = &PausedProvisioner{
+			PauseBefore: rawP.PauseBefore,
+			Provisioner: provisioner,
+		}
+	} else if rawP.Timeout > 0 {
+		provisioner = &TimeoutProvisioner{
+			Timeout:     rawP.Timeout,
+			Provisioner: provisioner,
+		}
+	}
+	cbp = coreBuildProvisioner{
+		pType:       rawP.Type,
+		provisioner: provisioner,
+		config:      config,
+	}
+
+	return cbp, nil
+}
+
 // Build returns the Build object for the given name.
 func (c *Core) Build(n string) (Build, error) {
 	// Setup the builder
@@ -140,46 +183,23 @@ func (c *Core) Build(n string) (Build, error) {
 		if rawP.OnlyExcept.Skip(rawName) {
 			continue
 		}
-
-		// Get the provisioner
-		provisioner, err := c.components.Provisioner(rawP.Type)
+		cbp, err := c.generateCoreBuildProvisioner(rawP, rawName)
 		if err != nil {
-			return nil, fmt.Errorf(
-				"error initializing provisioner '%s': %s",
-				rawP.Type, err)
-		}
-		if provisioner == nil {
-			return nil, fmt.Errorf(
-				"provisioner type not found: %s", rawP.Type)
+			return nil, err
 		}
 
-		// Get the configuration
-		config := make([]interface{}, 1, 2)
-		config[0] = rawP.Config
-		if rawP.Override != nil {
-			if override, ok := rawP.Override[rawName]; ok {
-				config = append(config, override)
-			}
-		}
+		provisioners = append(provisioners, cbp)
+	}
 
-		// If we're pausing, we wrap the provisioner in a special pauser.
-		if rawP.PauseBefore > 0 {
-			provisioner = &PausedProvisioner{
-				PauseBefore: rawP.PauseBefore,
-				Provisioner: provisioner,
-			}
-		} else if rawP.Timeout > 0 {
-			provisioner = &TimeoutProvisioner{
-				Timeout:     rawP.Timeout,
-				Provisioner: provisioner,
-			}
+	var cleanupProvisioner coreBuildProvisioner
+	if c.Template.CleanupProvisioner != nil {
+		// This is a special instantiation of the shell-local provisioner that
+		// is only run on error at end of provisioning step before other step
+		// cleanup occurs.
+		cleanupProvisioner, err = c.generateCoreBuildProvisioner(c.Template.CleanupProvisioner, rawName)
+		if err != nil {
+			return nil, err
 		}
-
-		provisioners = append(provisioners, coreBuildProvisioner{
-			pType:       rawP.Type,
-			provisioner: provisioner,
-			config:      config,
-		})
 	}
 
 	// Setup the post-processors
@@ -232,14 +252,15 @@ func (c *Core) Build(n string) (Build, error) {
 	// TODO hooks one day
 
 	return &coreBuild{
-		name:           n,
-		builder:        builder,
-		builderConfig:  configBuilder.Config,
-		builderType:    configBuilder.Type,
-		postProcessors: postProcessors,
-		provisioners:   provisioners,
-		templatePath:   c.Template.Path,
-		variables:      c.variables,
+		name:               n,
+		builder:            builder,
+		builderConfig:      configBuilder.Config,
+		builderType:        configBuilder.Type,
+		postProcessors:     postProcessors,
+		provisioners:       provisioners,
+		cleanupProvisioner: cleanupProvisioner,
+		templatePath:       c.Template.Path,
+		variables:          c.variables,
 	}, nil
 }
 

packer/hook.go

@@ -6,6 +6,7 @@ import (
 
 // This is the hook that should be fired for provisioners to run.
 const HookProvision = "packer_provision"
+const HookCleanupProvision = "packer_cleanup_provision"
 
 // A Hook is used to hook into an arbitrarily named location in a build,
 // allowing custom behavior to run at certain points along a build.

template/parse.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 	"os"
 	"path/filepath"
 	"sort"
@@ -28,6 +29,7 @@ type rawTemplate struct {
 	Push               map[string]interface{} `json:"push,omitempty"`
 	PostProcessors     []interface{}          `mapstructure:"post-processors" json:"post-processors,omitempty"`
 	Provisioners       []interface{}          `json:"provisioners,omitempty"`
+	CleanupProvisioner interface{}            `mapstructure:"on-error-script" json:"on-error-script,omitempty"`
 	Variables          map[string]interface{} `json:"variables,omitempty"`
 	SensitiveVariables []string               `mapstructure:"sensitive-variables" json:"sensitive-variables,omitempty"`
 
@@ -242,6 +244,38 @@ func (r *rawTemplate) Template() (*Template, error) {
 		result.Provisioners = append(result.Provisioners, &p)
 	}
 
+	// Gather the on-error-script
+	log.Printf("r.CleanupProvisioner is %#v", r.CleanupProvisioner)
+	if r.CleanupProvisioner != nil {
+		var p Provisioner
+		if err := r.decoder(&p, nil).Decode(r.CleanupProvisioner); err != nil {
+			errs = multierror.Append(errs, fmt.Errorf(
+				"On Error Cleanup provisioner: %s", err))
+		}
+
+		// Type is required before any richer validation
+		log.Printf("p is %#v", p)
+		if p.Type == "" {
+			errs = multierror.Append(errs, fmt.Errorf(
+				"on error cleanup provisioner missing 'type'"))
+		}
+
+		// Set the raw configuration and delete any special keys
+		p.Config = r.CleanupProvisioner.(map[string]interface{})
+
+		delete(p.Config, "except")
+		delete(p.Config, "only")
+		delete(p.Config, "override")
+		delete(p.Config, "pause_before")
+		delete(p.Config, "type")
+		delete(p.Config, "timeout")
+
+		if len(p.Config) == 0 {
+			p.Config = nil
+		}
+		result.CleanupProvisioner = &p
+	}
+
 	// If we have errors, return those with a nil result
 	if errs != nil {
 		return nil, errs

template/template.go

@@ -24,6 +24,7 @@ type Template struct {
 	SensitiveVariables []*Variable
 	Builders           map[string]*Builder
 	Provisioners       []*Provisioner
+	CleanupProvisioner *Provisioner
 	PostProcessors     [][]*PostProcessor
 
 	// RawContents is just the raw data for this template