From 87bc7415fc1bb4da7726d0ab18b5c2c4727de9c5 Mon Sep 17 00:00:00 2001
From: Marcel Jacek <72880145+marceljk@users.noreply.github.com>
Date: Wed, 15 Oct 2025 09:42:22 +0200
Subject: [PATCH] feat(dns): add validation for cname record-sets (#1019)

relates to #1014 and STACKITTPR-375
---
 stackit/internal/services/dns/recordset/resource.go |  3 +--
 stackit/internal/validate/validate.go               |  8 ++++++++
 stackit/internal/validate/validate_test.go          | 10 ++++++++--
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/stackit/internal/services/dns/recordset/resource.go b/stackit/internal/services/dns/recordset/resource.go
index 0d06449d..b00e67e6 100644
--- a/stackit/internal/services/dns/recordset/resource.go
+++ b/stackit/internal/services/dns/recordset/resource.go
@@ -5,8 +5,6 @@ import (
 	"fmt"
 	"strings"
 
-	dnsUtils "github.com/stackitcloud/terraform-provider-stackit/stackit/internal/services/dns/utils"
-
 	"github.com/hashicorp/terraform-plugin-framework-validators/int64validator"
 	"github.com/hashicorp/terraform-plugin-framework-validators/listvalidator"
 	"github.com/hashicorp/terraform-plugin-framework-validators/stringvalidator"
@@ -23,6 +21,7 @@ import (
 	"github.com/stackitcloud/stackit-sdk-go/services/dns/wait"
 	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/conversion"
 	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/core"
+	dnsUtils "github.com/stackitcloud/terraform-provider-stackit/stackit/internal/services/dns/utils"
 	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/utils"
 	"github.com/stackitcloud/terraform-provider-stackit/stackit/internal/validate"
 )
diff --git a/stackit/internal/validate/validate.go b/stackit/internal/validate/validate.go
index 593fad27..0af0f3c6 100644
--- a/stackit/internal/validate/validate.go
+++ b/stackit/internal/validate/validate.go
@@ -132,6 +132,14 @@ func RecordSet() *Validator {
 					))
 				}
 			case "CNAME":
+				name := req.ConfigValue.ValueString()
+				if name == "" || name[len(name)-1] != '.' {
+					resp.Diagnostics.Append(validatordiag.InvalidAttributeValueDiagnostic(
+						req.Path,
+						"value must be a Fully Qualified Domain Name (FQDN) and end with dot '.'",
+						req.ConfigValue.ValueString(),
+					))
+				}
 			case "NS":
 			case "MX":
 			case "TXT":
diff --git a/stackit/internal/validate/validate_test.go b/stackit/internal/validate/validate_test.go
index beb2ed75..3436a7a1 100644
--- a/stackit/internal/validate/validate_test.go
+++ b/stackit/internal/validate/validate_test.go
@@ -264,8 +264,14 @@ func TestRecordSet(t *testing.T) {
 			false,
 		},
 		{
-			"CNAME record",
-			"some-record",
+			"CNAME record Not a Fully Qualified Domain Name",
+			"stackit.de",
+			"CNAME",
+			false,
+		},
+		{
+			"CNAME record ok Fully Qualified Domain Name",
+			"stackit.de.",
 			"CNAME",
 			true,
 		},