Merge pull request #3885 from orivej/on-error

Add -on-error command line argument to allow preserving artifacts on builder errors

builder/amazon/chroot/builder.go

@@ -262,15 +262,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	)
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/amazon/ebs/builder.go

@@ -179,15 +179,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/amazon/instance/builder.go

@@ -262,15 +262,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/azure/arm/builder.go

@@ -157,7 +157,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		ui.Message(fmt.Sprintf("temp admin password: '%s'", b.config.Password))
 	}
 
-	b.runner = b.createRunner(&steps, ui)
+	b.runner = packerCommon.NewRunner(steps, b.config.PackerConfig, ui)
 	b.runner.Run(b.stateBag)
 
 	// Report any errors.
@@ -198,19 +198,6 @@ func (b *Builder) Cancel() {
 	}
 }
 
-func (b *Builder) createRunner(steps *[]multistep.Step, ui packer.Ui) multistep.Runner {
-	if b.config.PackerDebug {
-		return &multistep.DebugRunner{
-			Steps:   *steps,
-			PauseFn: packerCommon.MultistepDebugFn(ui),
-		}
-	}
-
-	return &multistep.BasicRunner{
-		Steps: *steps,
-	}
-}
-
 func (b *Builder) getBlobEndpoint(client *AzureClient, resourceGroupName string, storageAccountName string) (string, error) {
 	account, err := client.AccountsClient.GetProperties(resourceGroupName, storageAccountName)
 	if err != nil {

builder/digitalocean/builder.go

@@ -73,15 +73,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run the steps
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/docker/builder.go

@@ -78,15 +78,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	state.Put("driver", driver)
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/googlecompute/builder.go

@@ -73,14 +73,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run the steps.
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
 	b.runner.Run(state)
 
 	// Report any errors.

builder/null/builder.go

@@ -46,15 +46,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	state.Put("ui", ui)
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/openstack/builder.go

@@ -116,15 +116,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunner(steps, b.config.PackerConfig, ui)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: common.MultistepDebugFn(ui),
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/parallels/iso/builder.go

@@ -215,17 +215,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	state.Put("ui", ui)
 
 	// Run
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/parallels/pvm/builder.go

@@ -108,16 +108,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run the steps.
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
 	b.runner.Run(state)
 
 	// Report any errors.

builder/qemu/builder.go

@@ -422,17 +422,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	state.Put("ui", ui)
 
 	// Run
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/virtualbox/iso/builder.go

@@ -275,17 +275,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	state.Put("ui", ui)
 
 	// Run
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/virtualbox/ovf/builder.go

@@ -135,16 +135,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run the steps.
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
 	b.runner.Run(state)
 
 	// Report any errors.

builder/vmware/iso/builder.go

@@ -305,17 +305,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run!
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
-
 	b.runner.Run(state)
 
 	// If there was an error, return that

builder/vmware/vmx/builder.go

@@ -122,16 +122,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	}
 
 	// Run the steps.
-	if b.config.PackerDebug {
+	b.runner = common.NewRunnerWithPauseFn(steps, b.config.PackerConfig, ui, state)
-		pauseFn := common.MultistepDebugFn(ui)
-		state.Put("pauseFn", pauseFn)
-		b.runner = &multistep.DebugRunner{
-			Steps:   steps,
-			PauseFn: pauseFn,
-		}
-	} else {
-		b.runner = &multistep.BasicRunner{Steps: steps}
-	}
 	b.runner.Run(state)
 
 	// Report any errors.

command/build.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/mitchellh/packer/helper/enumflag"
 	"github.com/mitchellh/packer/packer"
 	"github.com/mitchellh/packer/template"
 )
@@ -20,11 +21,14 @@ type BuildCommand struct {
 
 func (c BuildCommand) Run(args []string) int {
 	var cfgColor, cfgDebug, cfgForce, cfgParallel bool
+	var cfgOnError string
 	flags := c.Meta.FlagSet("build", FlagSetBuildFilter|FlagSetVars)
 	flags.Usage = func() { c.Ui.Say(c.Help()) }
 	flags.BoolVar(&cfgColor, "color", true, "")
 	flags.BoolVar(&cfgDebug, "debug", false, "")
 	flags.BoolVar(&cfgForce, "force", false, "")
+	flagOnError := enumflag.New(&cfgOnError, "cleanup", "abort", "ask")
+	flags.Var(flagOnError, "on-error", "")
 	flags.BoolVar(&cfgParallel, "parallel", true, "")
 	if err := flags.Parse(args); err != nil {
 		return 1
@@ -99,12 +103,14 @@ func (c BuildCommand) Run(args []string) int {
 
 	log.Printf("Build debug mode: %v", cfgDebug)
 	log.Printf("Force build: %v", cfgForce)
+	log.Printf("On error: %v", cfgOnError)
 
 	// Set the debug and force mode and prepare all the builds
 	for _, b := range builds {
 		log.Printf("Preparing build: %s", b.Name())
 		b.SetDebug(cfgDebug)
 		b.SetForce(cfgForce)
+		b.SetOnError(cfgOnError)
 
 		warnings, err := b.Prepare()
 		if err != nil {
@@ -284,7 +290,7 @@ Options:
   -except=foo,bar,baz        Build all builds other than these
   -force                     Force a build to continue if artifacts exist, deletes existing artifacts
   -machine-readable          Machine-readable output
-  -only=foo,bar,baz          Only build the given builds by name
+  -on-error=[cleanup|abort|ask] If the build fails do: clean up (default), abort, or ask
   -parallel=false            Disable parallelization (on by default)
   -var 'key=value'           Variable for templates, can be used multiple times.
   -var-file=path             JSON file containing user variables.

common/multistep_runner.go

@@ -0,0 +1,154 @@
+package common
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"reflect"
+	"strings"
+	"time"
+
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+)
+
+func newRunner(steps []multistep.Step, config PackerConfig, ui packer.Ui) (multistep.Runner, multistep.DebugPauseFn) {
+	switch config.PackerOnError {
+	case "", "cleanup":
+	case "abort":
+		for i, step := range steps {
+			steps[i] = abortStep{step, ui}
+		}
+	case "ask":
+		for i, step := range steps {
+			steps[i] = askStep{step, ui}
+		}
+	}
+
+	if config.PackerDebug {
+		pauseFn := MultistepDebugFn(ui)
+		return &multistep.DebugRunner{Steps: steps, PauseFn: pauseFn}, pauseFn
+	} else {
+		return &multistep.BasicRunner{Steps: steps}, nil
+	}
+}
+
+// NewRunner returns a multistep.Runner that runs steps augmented with support
+// for -debug and -on-error command line arguments.
+func NewRunner(steps []multistep.Step, config PackerConfig, ui packer.Ui) multistep.Runner {
+	runner, _ := newRunner(steps, config, ui)
+	return runner
+}
+
+// NewRunnerWithPauseFn returns a multistep.Runner that runs steps augmented
+// with support for -debug and -on-error command line arguments.  With -debug it
+// puts the multistep.DebugPauseFn that will pause execution between steps into
+// the state under the key "pauseFn".
+func NewRunnerWithPauseFn(steps []multistep.Step, config PackerConfig, ui packer.Ui, state multistep.StateBag) multistep.Runner {
+	runner, pauseFn := newRunner(steps, config, ui)
+	if pauseFn != nil {
+		state.Put("pauseFn", pauseFn)
+	}
+	return runner
+}
+
+func typeName(i interface{}) string {
+	return reflect.Indirect(reflect.ValueOf(i)).Type().Name()
+}
+
+type abortStep struct {
+	step multistep.Step
+	ui   packer.Ui
+}
+
+func (s abortStep) Run(state multistep.StateBag) multistep.StepAction {
+	return s.step.Run(state)
+}
+
+func (s abortStep) Cleanup(state multistep.StateBag) {
+	if _, ok := state.GetOk(multistep.StateCancelled); ok {
+		s.ui.Error("Interrupted, aborting...")
+		os.Exit(1)
+	}
+	if _, ok := state.GetOk(multistep.StateHalted); ok {
+		s.ui.Error(fmt.Sprintf("Step %q failed, aborting...", typeName(s.step)))
+		os.Exit(1)
+	}
+	s.step.Cleanup(state)
+}
+
+type askStep struct {
+	step multistep.Step
+	ui   packer.Ui
+}
+
+func (s askStep) Run(state multistep.StateBag) (action multistep.StepAction) {
+	for {
+		action = s.step.Run(state)
+
+		if action != multistep.ActionHalt {
+			return
+		}
+
+		switch ask(s.ui, typeName(s.step), state) {
+		case askCleanup:
+			return
+		case askAbort:
+			os.Exit(1)
+		case askRetry:
+			continue
+		}
+	}
+}
+
+func (s askStep) Cleanup(state multistep.StateBag) {
+	s.step.Cleanup(state)
+}
+
+type askResponse int
+
+const (
+	askCleanup askResponse = iota
+	askAbort
+	askRetry
+)
+
+func ask(ui packer.Ui, name string, state multistep.StateBag) askResponse {
+	ui.Say(fmt.Sprintf("Step %q failed", name))
+
+	result := make(chan askResponse)
+	go func() {
+		result <- askPrompt(ui)
+	}()
+
+	for {
+		select {
+		case response := <-result:
+			return response
+		case <-time.After(100 * time.Millisecond):
+			if _, ok := state.GetOk(multistep.StateCancelled); ok {
+				return askCleanup
+			}
+		}
+	}
+}
+
+func askPrompt(ui packer.Ui) askResponse {
+	for {
+		line, err := ui.Ask("[c] Clean up and exit, [a] abort without cleanup, or [r] retry step (build may fail even if retry succeeds)?")
+		if err != nil {
+			log.Printf("Error asking for input: %s", err)
+		}
+
+		input := strings.ToLower(line) + "c"
+		switch input[0] {
+		case 'c':
+			return askCleanup
+		case 'a':
+			return askAbort
+		case 'r':
+			return askRetry
+		}
+		ui.Say(fmt.Sprintf("Incorrect input: %#v", line))
+	}
+}

common/packer_config.go

@@ -8,5 +8,6 @@ type PackerConfig struct {
 	PackerBuilderType string            `mapstructure:"packer_builder_type"`
 	PackerDebug       bool              `mapstructure:"packer_debug"`
 	PackerForce       bool              `mapstructure:"packer_force"`
+	PackerOnError     string            `mapstructure:"packer_on_error"`
 	PackerUserVars    map[string]string `mapstructure:"packer_user_variables"`
 }

helper/enumflag/flag.go

@@ -0,0 +1,28 @@
+package enumflag
+
+import "fmt"
+
+type enumFlag struct {
+	target  *string
+	options []string
+}
+
+// New returns a flag.Value implementation for parsing flags with a one-of-a-set value
+func New(target *string, options ...string) *enumFlag {
+	return &enumFlag{target: target, options: options}
+}
+
+func (f *enumFlag) String() string {
+	return *f.target
+}
+
+func (f *enumFlag) Set(value string) error {
+	for _, v := range f.options {
+		if v == value {
+			*f.target = value
+			return nil
+		}
+	}
+
+	return fmt.Errorf("expected one of %q", f.options)
+}

packer/build.go

@@ -24,6 +24,12 @@ const (
 	// force build is enabled.
 	ForceConfigKey = "packer_force"
 
+	// This key determines what to do when a normal multistep step fails
+	// - "cleanup" - run cleanup steps
+	// - "abort" - exit without cleanup
+	// - "ask" - ask the user
+	OnErrorConfigKey = "packer_on_error"
+
 	// TemplatePathKey is the path to the template that configured this build
 	TemplatePathKey = "packer_template_path"
 
@@ -67,6 +73,12 @@ type Build interface {
 	// When SetForce is set to true, existing artifacts from the build are
 	// deleted prior to the build.
 	SetForce(bool)
+
+	// SetOnError will determine what to do when a normal multistep step fails
+	// - "cleanup" - run cleanup steps
+	// - "abort" - exit without cleanup
+	// - "ask" - ask the user
+	SetOnError(string)
 }
 
 // A build struct represents a single build job, the result of which should
@@ -86,6 +98,7 @@ type coreBuild struct {
 
 	debug         bool
 	force         bool
+	onError       string
 	l             sync.Mutex
 	prepareCalled bool
 }
@@ -129,6 +142,7 @@ func (b *coreBuild) Prepare() (warn []string, err error) {
 		BuilderTypeConfigKey:   b.builderType,
 		DebugConfigKey:         b.debug,
 		ForceConfigKey:         b.force,
+		OnErrorConfigKey:       b.onError,
 		TemplatePathKey:        b.templatePath,
 		UserVariablesConfigKey: b.variables,
 	}
@@ -306,6 +320,14 @@ func (b *coreBuild) SetForce(val bool) {
 	b.force = val
 }
 
+func (b *coreBuild) SetOnError(val string) {
+	if b.prepareCalled {
+		panic("prepare has already been called")
+	}
+
+	b.onError = val
+}
+
 // Cancels the build if it is running.
 func (b *coreBuild) Cancel() {
 	b.builder.Cancel()

packer/build_test.go

@@ -23,6 +23,7 @@ func testBuild() *coreBuild {
 			},
 		},
 		variables: make(map[string]string),
+		onError:   "cleanup",
 	}
 }
 
@@ -32,6 +33,7 @@ func testDefaultPackerConfig() map[string]interface{} {
 		BuilderTypeConfigKey:   "foo",
 		DebugConfigKey:         false,
 		ForceConfigKey:         false,
+		OnErrorConfigKey:       "cleanup",
 		TemplatePathKey:        "",
 		UserVariablesConfigKey: make(map[string]string),
 	}

packer/rpc/build.go

@@ -1,8 +1,9 @@
 package rpc
 
 import (
-	"github.com/mitchellh/packer/packer"
 	"net/rpc"
+
+	"github.com/mitchellh/packer/packer"
 )
 
 // An implementation of packer.Build where the build is actually executed
@@ -79,6 +80,12 @@ func (b *build) SetForce(val bool) {
 	}
 }
 
+func (b *build) SetOnError(val string) {
+	if err := b.client.Call("Build.SetOnError", val, new(interface{})); err != nil {
+		panic(err)
+	}
+}
+
 func (b *build) Cancel() {
 	if err := b.client.Call("Build.Cancel", new(interface{}), new(interface{})); err != nil {
 		panic(err)
@@ -134,6 +141,11 @@ func (b *BuildServer) SetForce(val *bool, reply *interface{}) error {
 	return nil
 }
 
+func (b *BuildServer) SetOnError(val *string, reply *interface{}) error {
+	b.build.SetOnError(*val)
+	return nil
+}
+
 func (b *BuildServer) Cancel(args *interface{}, reply *interface{}) error {
 	b.build.Cancel()
 	return nil

packer/rpc/build_test.go

@@ -2,9 +2,10 @@ package rpc
 
 import (
 	"errors"
-	"github.com/mitchellh/packer/packer"
 	"reflect"
 	"testing"
+
+	"github.com/mitchellh/packer/packer"
 )
 
 var testBuildArtifact = &packer.MockArtifact{}
@@ -18,6 +19,7 @@ type testBuild struct {
 	runUi            packer.Ui
 	setDebugCalled   bool
 	setForceCalled   bool
+	setOnErrorCalled bool
 	cancelCalled     bool
 
 	errRunResult bool
@@ -53,6 +55,10 @@ func (b *testBuild) SetForce(bool) {
 	b.setForceCalled = true
 }
 
+func (b *testBuild) SetOnError(string) {
+	b.setOnErrorCalled = true
+}
+
 func (b *testBuild) Cancel() {
 	b.cancelCalled = true
 }
@@ -116,6 +122,12 @@ func TestBuild(t *testing.T) {
 		t.Fatal("should be called")
 	}
 
+	// Test SetOnError
+	bClient.SetOnError("ask")
+	if !b.setOnErrorCalled {
+		t.Fatal("should be called")
+	}
+
 	// Test Cancel
 	bClient.Cancel()
 	if !b.cancelCalled {

website/source/docs/command-line/build.html.md

@@ -36,7 +36,17 @@ artifacts that are created will be outputted at the end of the build.
     remove the artifacts from the previous build. This will allow the user to
     repeat a build without having to manually clean these artifacts beforehand.
 
+-   `-on-error=cleanup` (default), `-on-error=abort`, `-on-error=ask` - Selects
+    what to do when the build fails.  `cleanup` cleans up after the previous
+    steps, deleting temporary files and virtual machines.  `abort` exits without
+    any cleanup, which might require the next build to use `-force`.  `ask`
+    presents a prompt and waits for you to decide to clean up, abort, or retry
+    the failed step.
+
 -   `-only=foo,bar,baz` - Only build the builds with the given
     comma-separated names. Build names by default are the names of their
     builders, unless a specific `name` attribute is specified within
     the configuration.
+
+-   `-parallel=false` - Disable parallelization of multiple builders (on by
+    default).