make HCL2 respect the new builder-returned generated vars list

hcl2template/types.build.provisioners.go

@@ -3,6 +3,7 @@ package hcl2template
 import (
 	"fmt"
 	"github.com/hashicorp/hcl/v2"
+	"github.com/hashicorp/packer/helper/common"
 	"github.com/hashicorp/packer/packer"
 )
 
@@ -31,7 +32,7 @@ func (p *Parser) decodeProvisioner(block *hcl.Block) (*ProvisionerBlock, hcl.Dia
 	return provisioner, diags
 }
 
-func (p *Parser) StartProvisioner(pb *ProvisionerBlock) (packer.Provisioner, hcl.Diagnostics) {
+func (p *Parser) StartProvisioner(pb *ProvisionerBlock, generatedVars []string) (packer.Provisioner, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 
 	provisioner, err := p.ProvisionersSchemas.Start(pb.PType)
@@ -43,12 +44,30 @@ func (p *Parser) StartProvisioner(pb *ProvisionerBlock) (packer.Provisioner, hcl
 		})
 		return nil, diags
 	}
-	flatProvisinerCfg, moreDiags := decodeHCL2Spec(pb.block, nil, provisioner)
+	flatProvisionerCfg, moreDiags := decodeHCL2Spec(pb.block, nil, provisioner)
 	diags = append(diags, moreDiags...)
 	if diags.HasErrors() {
 		return nil, diags
 	}
-	err = provisioner.Prepare(flatProvisinerCfg)
+	// 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)
+	err = provisioner.Prepare(flatProvisionerCfg, generatedPlaceholderMap)
 	if err != nil {
 		diags = append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,

hcl2template/types.packer_config.go

@@ -14,11 +14,11 @@ type PackerConfig struct {
 	Builds Builds
 }
 
-func (p *Parser) CoreBuildProvisioners(blocks []*ProvisionerBlock) ([]packer.CoreBuildProvisioner, hcl.Diagnostics) {
+func (p *Parser) CoreBuildProvisioners(blocks []*ProvisionerBlock, generatedVars []string) ([]packer.CoreBuildProvisioner, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 	res := []packer.CoreBuildProvisioner{}
 	for _, pb := range blocks {
-		provisioner, moreDiags := p.StartProvisioner(pb)
+		provisioner, moreDiags := p.StartProvisioner(pb, generatedVars)
 		diags = append(diags, moreDiags...)
 		if moreDiags.HasErrors() {
 			continue
@@ -63,12 +63,12 @@ func (p *Parser) getBuilds(cfg *PackerConfig) ([]packer.Build, hcl.Diagnostics)
 				})
 				continue
 			}
-			builder, moreDiags := p.StartBuilder(src)
+			builder, moreDiags, generatedVars := p.StartBuilder(src)
 			diags = append(diags, moreDiags...)
 			if moreDiags.HasErrors() {
 				continue
 			}
-			provisioners, moreDiags := p.CoreBuildProvisioners(build.ProvisionerBlocks)
+			provisioners, moreDiags := p.CoreBuildProvisioners(build.ProvisionerBlocks, generatedVars)
 			diags = append(diags, moreDiags...)
 			if moreDiags.HasErrors() {
 				continue

hcl2template/types.source.go

@@ -39,7 +39,7 @@ func (p *Parser) decodeSource(block *hcl.Block) (*Source, hcl.Diagnostics) {
 	return source, diags
 }
 
-func (p *Parser) StartBuilder(source *Source) (packer.Builder, hcl.Diagnostics) {
+func (p *Parser) StartBuilder(source *Source) (packer.Builder, hcl.Diagnostics, []string) {
 	var diags hcl.Diagnostics
 
 	// calling BuilderSchemas will start a new builder plugin to ask about
@@ -53,19 +53,19 @@ func (p *Parser) StartBuilder(source *Source) (packer.Builder, hcl.Diagnostics)
 			Detail:  err.Error(),
 			Subject: &source.block.LabelRanges[0],
 		})
-		return builder, diags
+		return builder, diags, nil
 	}
 
 	decoded, moreDiags := decodeHCL2Spec(source.block, nil, builder)
 	diags = append(diags, moreDiags...)
 	if moreDiags.HasErrors() {
-		return nil, diags
+		return nil, diags, nil
 	}
 
-	_, warning, err := builder.Prepare(decoded)
+	generatedVars, warning, err := builder.Prepare(decoded)
 	moreDiags = warningErrorsToDiags(source.block, warning, err)
 	diags = append(diags, moreDiags...)
-	return builder, diags
+	return builder, diags, generatedVars
 }
 
 func (source *Source) Ref() SourceRef {