provider/azurerm: Add Validation to the Azurerm LoadBalancer Rule name

builtin/providers/azurerm/resource_arm_loadbalancer_rule.go

@@ -3,6 +3,7 @@ package azurerm
 import (
 	"fmt"
 	"log"
+	"regexp"
 	"time"
 
 	"github.com/Azure/azure-sdk-for-go/arm/network"
@@ -21,9 +22,10 @@ func resourceArmLoadbalancerRule() *schema.Resource {
 
 		Schema: map[string]*schema.Schema{
 			"name": {
-				Type:     schema.TypeString,
-				Required: true,
-				ForceNew: true,
+				Type:         schema.TypeString,
+				Required:     true,
+				ForceNew:     true,
+				ValidateFunc: validateArmLoadBalancerRuleName,
 			},
 
 			"location": {
@@ -308,3 +310,33 @@ func expandAzureRmLoadbalancerRule(d *schema.ResourceData, lb *network.LoadBalan
 
 	return &lbRule, nil
 }
+
+func validateArmLoadBalancerRuleName(v interface{}, k string) (ws []string, errors []error) {
+	value := v.(string)
+	if !regexp.MustCompile(`^[a-zA-Z._-]+$`).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"only word characters and hyphens allowed in %q: %q",
+			k, value))
+	}
+
+	if len(value) > 80 {
+		errors = append(errors, fmt.Errorf(
+			"%q cannot be longer than 80 characters: %q", k, value))
+	}
+
+	if len(value) == 0 {
+		errors = append(errors, fmt.Errorf(
+			"%q cannot be an empty string: %q", k, value))
+	}
+	if !regexp.MustCompile(`[a-zA-Z]$`).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"%q must end with a word character: %q", k, value))
+	}
+
+	if !regexp.MustCompile(`^[a-zA-Z]`).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"%q must start with a word character: %q", k, value))
+	}
+
+	return
+}

builtin/providers/azurerm/resource_arm_loadbalancer_rule_test.go

@@ -10,6 +10,54 @@ import (
 	"github.com/hashicorp/terraform/terraform"
 )
 
+func TestResourceAzureRMLoadBalancerRuleNameLabel_validation(t *testing.T) {
+	cases := []struct {
+		Value    string
+		ErrCount int
+	}{
+		{
+			Value:    "-word",
+			ErrCount: 1,
+		},
+		{
+			Value:    "testing-",
+			ErrCount: 1,
+		},
+		{
+			Value:    "test123test",
+			ErrCount: 1,
+		},
+		{
+			Value:    acctest.RandStringFromCharSet(81, "abcdedfed"),
+			ErrCount: 1,
+		},
+		{
+			Value:    "test.rule",
+			ErrCount: 0,
+		},
+		{
+			Value:    "test_rule",
+			ErrCount: 0,
+		},
+		{
+			Value:    "test-rule",
+			ErrCount: 0,
+		},
+		{
+			Value:    "TestRule",
+			ErrCount: 0,
+		},
+	}
+
+	for _, tc := range cases {
+		_, errors := validateArmLoadBalancerRuleName(tc.Value, "azurerm_lb_rule")
+
+		if len(errors) != tc.ErrCount {
+			t.Fatalf("Expected the Azure RM LoadBalancer Rule Name Label to trigger a validation error")
+		}
+	}
+}
+
 func TestAccAzureRMLoadbalancerRule_basic(t *testing.T) {
 	var lb network.LoadBalancer
 	ri := acctest.RandInt()

website/source/docs/providers/azurerm/r/loadbalancer_rule.html.markdown

@@ -42,7 +42,7 @@ resource "azurerm_lb_rule" "test" {
   location = "West US"
   resource_group_name = "${azurerm_resource_group.test.name}"
   loadbalancer_id = "${azurerm_lb.test.id}"
-  name = "LB Rule"
+  name = "LBRule"
   protocol = "Tcp"
   frontend_port = 3389
   backend_port = 3389