hcl2template: check bucket name at parse-time

Not validating the bucket's name during parse leads to configurations
being marked as valid, even if the bucket name is not, which will fail
during a real build afterwards.

To avoid this problem and fail with an error as quickly as possible, we
add a check during parsing, so that it gets reported for validate as
well.

hcl2template/testdata/hcp_par/invalid_bucket.pkr.hcl

@@ -0,0 +1,12 @@
+source "null" "test" {
+  communicator = "none"
+}
+
+build {
+  name = "bucket-slug"
+  hcp_packer_registry {
+    bucket_name = "invalid_bucket"
+  }
+
+  sources = ["null.test"]
+}

hcl2template/testdata/hcp_par/long-description.pkr.hcl

@@ -1,3 +1,7 @@
+source "null" "test" {
+  communicator = "none"
+}
+
 build {
   name = "bucket-slug"
   hcp_packer_registry {
@@ -7,4 +11,6 @@ super super super super super super super super super super super super super su
 super super super long description
     EOT
   }
+
+  sources = ["null.test"]
 }

hcl2template/testdata/hcp_par/long_bucket.pkr.hcl

@@ -0,0 +1,12 @@
+source "null" "test" {
+  communicator = "none"
+}
+
+build {
+  name = "bucket-slug"
+  hcp_packer_registry {
+    bucket_name = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"
+  }
+
+  sources = ["null.test"]
+}

hcl2template/testdata/hcp_par/ok_bucket.pkr.hcl

@@ -0,0 +1,12 @@
+source "null" "test" {
+  communicator = "none"
+}
+
+build {
+  name = "bucket-slug"
+  hcp_packer_registry {
+    bucket_name = "ok-Bucket-name-1"
+  }
+
+  sources = ["null.test"]
+}

hcl2template/testdata/hcp_par/short_bucket.pkr.hcl

@@ -0,0 +1,12 @@
+source "null" "test" {
+  communicator = "none"
+}
+
+build {
+  name = "bucket-slug"
+  hcp_packer_registry {
+    bucket_name = "ba"
+  }
+
+  sources = ["null.test"]
+}

hcl2template/types.build.hcp_packer_registry.go

@@ -5,6 +5,7 @@ package hcl2template
 
 import (
 	"fmt"
+	"regexp"
 
 	"github.com/hashicorp/hcl/v2"
 	"github.com/hashicorp/hcl/v2/gohcl"
@@ -23,6 +24,8 @@ type HCPPackerRegistryBlock struct {
 	HCL2Ref
 }
 
+var bucketNameRegexp = regexp.MustCompile("^[a-zA-Z0-9-]{3,36}$")
+
 func (p *Parser) decodeHCPRegistry(block *hcl.Block, cfg *PackerConfig) (*HCPPackerRegistryBlock, hcl.Diagnostics) {
 	par := &HCPPackerRegistryBlock{}
 	body := block.Body
@@ -51,6 +54,14 @@ func (p *Parser) decodeHCPRegistry(block *hcl.Block, cfg *PackerConfig) (*HCPPac
 		return nil, diags
 	}
 
+	if !bucketNameRegexp.MatchString(b.Slug) {
+		diags = diags.Append(&hcl.Diagnostic{
+			Severity: hcl.DiagError,
+			Summary:  fmt.Sprintf("%s.bucket_name can only contain between 3 and 36 ASCII letters, numbers and hyphens", buildHCPPackerRegistryLabel),
+			Subject:  block.DefRange.Ptr(),
+		})
+	}
+
 	par.Slug = b.Slug
 	par.Description = b.Description
 

hcl2template/types.build.hcp_packer_registry_test.go

@@ -7,7 +7,9 @@ import (
 	"path/filepath"
 	"testing"
 
+	"github.com/hashicorp/hcl/v2"
 	packersdk "github.com/hashicorp/packer-plugin-sdk/packer"
+	"github.com/hashicorp/packer/builder/null"
 	"github.com/hashicorp/packer/packer"
 	"github.com/zclconf/go-cty/cty"
 )
@@ -129,11 +131,120 @@ func Test_ParseHCPPackerRegistryBlock(t *testing.T) {
 			&PackerConfig{
 				CorePackerVersionString: lockedVersion,
 				Basedir:                 filepath.Join("testdata", "hcp_par"),
+				Sources: map[SourceRef]SourceBlock{
+					refNull: {
+						Type: "null",
+						Name: "test",
+						block: &hcl.Block{
+							Type: "source",
+						},
+					},
+				},
+			},
+			true, true,
+			nil,
+			false,
+		},
+		{"bucket name too short",
+			defaultParser,
+			parseTestArgs{"testdata/hcp_par/short_bucket.pkr.hcl", nil, nil},
+			&PackerConfig{
+				CorePackerVersionString: lockedVersion,
+				Basedir:                 filepath.Join("testdata", "hcp_par"),
+				Sources: map[SourceRef]SourceBlock{
+					refNull: {
+						Type: "null",
+						Name: "test",
+						block: &hcl.Block{
+							Type: "source",
+						},
+					},
+				},
 			},
 			true, true,
 			nil,
 			false,
 		},
+		{"bucket name too long",
+			defaultParser,
+			parseTestArgs{"testdata/hcp_par/long_bucket.pkr.hcl", nil, nil},
+			&PackerConfig{
+				CorePackerVersionString: lockedVersion,
+				Basedir:                 filepath.Join("testdata", "hcp_par"),
+				Sources: map[SourceRef]SourceBlock{
+					refNull: {
+						Type: "null",
+						Name: "test",
+						block: &hcl.Block{
+							Type: "source",
+						},
+					},
+				},
+			},
+			true, true,
+			nil,
+			false,
+		},
+		{"bucket name invalid chars",
+			defaultParser,
+			parseTestArgs{"testdata/hcp_par/invalid_bucket.pkr.hcl", nil, nil},
+			&PackerConfig{
+				CorePackerVersionString: lockedVersion,
+				Basedir:                 filepath.Join("testdata", "hcp_par"),
+				Sources: map[SourceRef]SourceBlock{
+					refNull: {
+						Type: "null",
+						Name: "test",
+						block: &hcl.Block{
+							Type: "source",
+						},
+					},
+				},
+			},
+			true, true,
+			nil,
+			false,
+		},
+		{"bucket name OK",
+			defaultParser,
+			parseTestArgs{"testdata/hcp_par/ok_bucket.pkr.hcl", nil, nil},
+			&PackerConfig{
+				CorePackerVersionString: lockedVersion,
+				Basedir:                 filepath.Join("testdata", "hcp_par"),
+				Sources: map[SourceRef]SourceBlock{
+					refNull: {
+						Type: "null",
+						Name: "test",
+						block: &hcl.Block{
+							Type: "source",
+						},
+					},
+				},
+				Builds: Builds{
+					{
+						Name:              "bucket-slug",
+						HCPPackerRegistry: &HCPPackerRegistryBlock{Slug: "ok-Bucket-name-1"},
+						Sources: []SourceUseBlock{
+							{
+								SourceRef: refNull,
+							},
+						},
+					},
+				},
+			},
+			false, false,
+			[]packersdk.Build{
+				&packer.CoreBuild{
+					BuildName:      "bucket-slug",
+					Type:           "null.test",
+					Builder:        &null.Builder{},
+					Provisioners:   []packer.CoreBuildProvisioner{},
+					PostProcessors: [][]packer.CoreBuildPostProcessor{},
+					Prepared:       true,
+				},
+			},
+			false,
+		},
 	}
 	testParse(t, tests)
 }

hcl2template/types.packer_config_test.go

@@ -22,6 +22,7 @@ var (
 	refVBIsoUbuntu1204  = SourceRef{Type: "virtualbox-iso", Name: "ubuntu-1204"}
 	refAWSEBSUbuntu1604 = SourceRef{Type: "amazon-ebs", Name: "ubuntu-1604"}
 	refAWSV3MyImage     = SourceRef{Type: "amazon-v3-ebs", Name: "my-image"}
+	refNull             = SourceRef{Type: "null", Name: "test"}
 	pTrue               = pointerToBool(true)
 )