Update ConvertToDNS1123() to validate and fix other special characters, max len and starts-with rules (#298)

* Update ConvertToDNS1123 helper function

* Update ConvertDNS1123() to handle corner cases

* Move consts to consts.go file

Co-authored-by: Nitish Malhotra <nitish.malhotra@gmail.com>

pkg/utils/chart.go

@@ -1,15 +1,5 @@
 package utils
 
-const (
-	DNS1123NameMaximumLength = 63
-
-	// subchartNameMaxLen is the maximum length of a subchart name.
-	//
-	// The max name length limit enforced by DNS1123 is 63 chars. We reserve 10 chars
-	// for concatenating application name hash.
-	subchartNameMaxLen = 53
-)
-
 func GetSubchartName(appName, scName string) string {
 	scName = TruncateString(scName, subchartNameMaxLen)
 	appName = TruncateString(GetHash(appName), DNS1123NameMaximumLength-len(scName)-1)

pkg/utils/consts.go

@@ -0,0 +1,13 @@
+package utils
+
+const (
+	DNS1123NameMaximumLength    = 63
+	DNS1123NotAllowedChars      = "[^-a-z0-9]"
+	DNS1123NotAllowedStartChars = "^[^a-z0-9]+"
+
+	// subchartNameMaxLen is the maximum length of a subchart name.
+	//
+	// The max name length limit enforced by DNS1123 is 63 chars. We reserve 10 chars
+	// for concatenating application name hash.
+	subchartNameMaxLen = 53
+)

pkg/utils/helpers.go

@@ -4,6 +4,7 @@ import (
 	"crypto/sha256"
 	"encoding/hex"
 	"fmt"
+	"regexp"
 	"strings"
 
 	fluxhelmv2beta1 "github.com/fluxcd/helm-controller/api/v2beta1"
@@ -12,7 +13,18 @@ import (
 )
 
 func ConvertToDNS1123(in string) string {
-	return strings.ReplaceAll(in, "_", "-")
+	name := strings.ToLower(in)
+
+	notAllowedChars := regexp.MustCompile(DNS1123NotAllowedChars)
+	name = notAllowedChars.ReplaceAllString(name, "-")
+
+	notAllowedStartChars := regexp.MustCompile(DNS1123NotAllowedStartChars)
+	name = notAllowedStartChars.ReplaceAllString(name, "")
+
+	if name == "" {
+		name = GetHash(in)
+	}
+	return TruncateString(name, DNS1123NameMaximumLength)
 }
 
 func ConvertSliceToDNS1123(in []string) []string {

pkg/utils/helpers_test.go

@@ -4,6 +4,60 @@ import (
 	"testing"
 )
 
+func TestConvertToDNS1123(t *testing.T) {
+	type args struct {
+		in string
+	}
+	tests := []struct {
+		name string
+		args args
+		want string
+	}{
+		{
+			name: "testing valid name",
+			args: args{
+				in: "good-small-name",
+			},
+			want: "good-small-name",
+		},
+		{
+			name: "testing invalid name",
+			args: args{
+				in: "tOk3_??ofTHE-Runner",
+			},
+			want: "tok3---ofthe-runner",
+		},
+		{
+			name: "testing all characters are invalid",
+			args: args{
+				in: "?.?&^%#$@_??",
+			},
+			want: GetHash("?.?&^%#$@_??")[0:63],
+		},
+		{
+			name: "testing invalid start chars",
+			args: args{
+				in: "----??tOk3_??ofTHE-Runner",
+			},
+			want: "tok3---ofthe-runner",
+		},
+		{
+			name: "testing very long name",
+			args: args{
+				in: "very-long-name------------------------------------------------end",
+			},
+			want: "very-long-name------------------------------------------------e",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ConvertToDNS1123(tt.args.in); got != tt.want {
+				t.Errorf("ConvertDNS1123() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
 func TestTruncateString(t *testing.T) {
 	type args struct {
 		in  string