Avoid calling CoreBuild.Prepare(...) for HCL2 templates (#8742)

hcl2template/types.build.post-processor.go

@@ -49,7 +49,7 @@ func (p *Parser) decodePostProcessor(block *hcl.Block) (*PostProcessorBlock, hcl
 	return postProcessor, diags
 }
 
-func (p *Parser) startPostProcessor(pp *PostProcessorBlock, ectx *hcl.EvalContext) (packer.PostProcessor, hcl.Diagnostics) {
+func (p *Parser) startPostProcessor(pp *PostProcessorBlock, ectx *hcl.EvalContext, generatedVars map[string]string) (packer.PostProcessor, hcl.Diagnostics) {
 	// ProvisionerBlock represents a detected but unparsed provisioner
 	var diags hcl.Diagnostics
 
@@ -64,7 +64,7 @@ func (p *Parser) startPostProcessor(pp *PostProcessorBlock, ectx *hcl.EvalContex
 	}
 	flatProvisinerCfg, moreDiags := decodeHCL2Spec(pp.Rest, ectx, postProcessor)
 	diags = append(diags, moreDiags...)
-	err = postProcessor.Configure(flatProvisinerCfg)
+	err = postProcessor.Configure(flatProvisinerCfg, generatedVars)
 	if err != nil {
 		diags = append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,

hcl2template/types.build.provisioners.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
-	"github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 )
 
@@ -47,7 +46,7 @@ func (p *Parser) decodeProvisioner(block *hcl.Block) (*ProvisionerBlock, hcl.Dia
 	return provisioner, diags
 }
 
-func (p *Parser) startProvisioner(pb *ProvisionerBlock, ectx *hcl.EvalContext, generatedVars []string) (packer.Provisioner, hcl.Diagnostics) {
+func (p *Parser) startProvisioner(pb *ProvisionerBlock, ectx *hcl.EvalContext, generatedVars map[string]string) (packer.Provisioner, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 
 	provisioner, err := p.ProvisionersSchemas.Start(pb.PType)
@@ -67,22 +66,10 @@ func (p *Parser) startProvisioner(pb *ProvisionerBlock, ectx *hcl.EvalContext, g
 	// manipulate generatedVars from builder to add to the interfaces being
 	// passed to the provisioner Prepare()
 
-	// If the builder has provided a list of to-be-generated variables that
-	// should be made accessible to provisioners, pass that list into
-	// the provisioner prepare() so that the provisioner can appropriately
-	// validate user input against what will become available. Otherwise,
-	// only pass the default variables, using the basic placeholder data.
-	generatedPlaceholderMap := packer.BasicPlaceholderData()
-	if generatedVars != nil {
-		for _, k := range generatedVars {
-			generatedPlaceholderMap[k] = fmt.Sprintf("Generated_%s. "+
-				common.PlaceholderMsg, k)
-		}
-	}
 	// configs := make([]interface{}, 2)
 	// configs = append(, flatProvisionerCfg)
-	// configs = append(configs, generatedPlaceholderMap)
+	// configs = append(configs, generatedVars)
-	err = provisioner.Prepare(flatProvisionerCfg, generatedPlaceholderMap)
+	err = provisioner.Prepare(flatProvisionerCfg, generatedVars)
 	if err != nil {
 		diags = append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,

hcl2template/types.packer_config.go

@@ -1,7 +1,9 @@
 package hcl2template
 
 import (
+	"fmt"
 	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 	"github.com/zclconf/go-cty/cty"
 )
@@ -42,7 +44,7 @@ func (cfg *PackerConfig) EvalContext() *hcl.EvalContext {
 
 // getCoreBuildProvisioners takes a list of provisioner block, starts according
 // provisioners and sends parsed HCL2 over to it.
-func (p *Parser) getCoreBuildProvisioners(blocks []*ProvisionerBlock, ectx *hcl.EvalContext, generatedVars []string) ([]packer.CoreBuildProvisioner, hcl.Diagnostics) {
+func (p *Parser) getCoreBuildProvisioners(blocks []*ProvisionerBlock, ectx *hcl.EvalContext, generatedVars map[string]string) ([]packer.CoreBuildProvisioner, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 	res := []packer.CoreBuildProvisioner{}
 	for _, pb := range blocks {
@@ -62,11 +64,11 @@ func (p *Parser) getCoreBuildProvisioners(blocks []*ProvisionerBlock, ectx *hcl.
 
 // getCoreBuildProvisioners takes a list of post processor block, starts
 // according provisioners and sends parsed HCL2 over to it.
-func (p *Parser) getCoreBuildPostProcessors(blocks []*PostProcessorBlock, ectx *hcl.EvalContext) ([]packer.CoreBuildPostProcessor, hcl.Diagnostics) {
+func (p *Parser) getCoreBuildPostProcessors(blocks []*PostProcessorBlock, ectx *hcl.EvalContext, generatedVars map[string]string) ([]packer.CoreBuildPostProcessor, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 	res := []packer.CoreBuildPostProcessor{}
 	for _, ppb := range blocks {
-		postProcessor, moreDiags := p.startPostProcessor(ppb, ectx)
+		postProcessor, moreDiags := p.startPostProcessor(ppb, ectx, generatedVars)
 		diags = append(diags, moreDiags...)
 		if moreDiags.HasErrors() {
 			continue
@@ -104,12 +106,26 @@ func (p *Parser) getBuilds(cfg *PackerConfig) ([]packer.Build, hcl.Diagnostics)
 			if moreDiags.HasErrors() {
 				continue
 			}
-			provisioners, moreDiags := p.getCoreBuildProvisioners(build.ProvisionerBlocks, cfg.EvalContext(), generatedVars)
+
+			// If the builder has provided a list of to-be-generated variables that
+			// should be made accessible to provisioners, pass that list into
+			// the provisioner prepare() so that the provisioner can appropriately
+			// validate user input against what will become available. Otherwise,
+			// only pass the default variables, using the basic placeholder data.
+			generatedPlaceholderMap := packer.BasicPlaceholderData()
+			if generatedVars != nil {
+				for _, k := range generatedVars {
+					generatedPlaceholderMap[k] = fmt.Sprintf("Build_%s. "+
+						common.PlaceholderMsg, k)
+				}
+			}
+
+			provisioners, moreDiags := p.getCoreBuildProvisioners(build.ProvisionerBlocks, cfg.EvalContext(), generatedPlaceholderMap)
 			diags = append(diags, moreDiags...)
 			if moreDiags.HasErrors() {
 				continue
 			}
-			postProcessors, moreDiags := p.getCoreBuildPostProcessors(build.PostProcessors, cfg.EvalContext())
+			postProcessors, moreDiags := p.getCoreBuildPostProcessors(build.PostProcessors, cfg.EvalContext(), generatedPlaceholderMap)
 			pps := [][]packer.CoreBuildPostProcessor{}
 			if len(postProcessors) > 0 {
 				pps = [][]packer.CoreBuildPostProcessor{postProcessors}
@@ -124,6 +140,7 @@ func (p *Parser) getBuilds(cfg *PackerConfig) ([]packer.Build, hcl.Diagnostics)
 				Builder:        builder,
 				Provisioners:   provisioners,
 				PostProcessors: pps,
+				Prepared:       true,
 			}
 			res = append(res, pcb)
 		}

hcl2template/types.packer_config_test.go

@@ -58,6 +58,7 @@ func TestParser_complete(t *testing.T) {
 			[]packer.Build{
 				&packer.CoreBuild{
 					Type:     "virtualbox-iso",
+					Prepared: true,
 					Builder:  basicMockBuilder,
 					Provisioners: []packer.CoreBuildProvisioner{
 						{

packer/build.go

@@ -97,6 +97,9 @@ type CoreBuild struct {
 	TemplatePath       string
 	Variables          map[string]string
 
+	// Indicates whether the build is already initialized before calling Prepare(..)
+	Prepared bool
+
 	debug         bool
 	force         bool
 	onError       string
@@ -132,6 +135,13 @@ func (b *CoreBuild) Name() string {
 // and any hooks. This _must_ be called prior to Run. The parameter is the
 // overrides for the variables within the template (if any).
 func (b *CoreBuild) Prepare() (warn []string, err error) {
+	// For HCL2 templates, the builder and hooks are initialized when the template is parsed.
+	// Calling Prepare(...) is not necessary
+	if b.Prepared {
+		b.prepareCalled = true
+		return
+	}
+
 	b.l.Lock()
 	defer b.l.Unlock()
 

packer/build_test.go

@@ -88,6 +88,17 @@ func TestBuild_Prepare(t *testing.T) {
 	}
 }
 
+func TestBuild_Prepare_SkipWhenBuilderAlreadyInitialized(t *testing.T) {
+	build := testBuild()
+	builder := build.Builder.(*MockBuilder)
+
+	build.Prepared = true
+	build.Prepare()
+	if builder.PrepareCalled {
+		t.Fatal("should not be called")
+	}
+}
+
 func TestBuild_Prepare_Twice(t *testing.T) {
 	build := testBuild()
 	warn, err := build.Prepare()